# Hinode EIS: updated in-flight radiometric calibration

G. Del Zanna DAMTP, Center for Mathematical Sciences, University of Cambridge,
Wilberforce Road, Cambridge, CB3 0WA, UK  M. Weberg Department of Physics and
Astronomy, George Mason University, Fairfax, VA, USA  H. P. Warren Space
Science Division, Naval Research Laboratory, Washington, DC 20375, USA

###### Abstract

We present an update to the in-flight radiometric calibration of the Hinode
EUV Imaging Spectrometer (EIS), revising and extending our previous studies.
We analyze full-spectral EIS observations of quiet Sun and active regions from
2007 until 2022. Using CHIANTI version 10, we adjust the EIS relative
effective areas for a selection of dates with emission measure analyses of
off-limb quiet Sun. We find generally good agreement (within typically $\pm$
15%) between measured and expected line intensities. We then consider selected
intensity ratios for all the dates and apply an automatic fitting method to
adjust the relative effective areas. To constrain the absolute values from
2010 we force agreement between EIS and Solar Dynamics Observatory (SDO)
Atmospheric Imaging Assembly (AIA) 193 Å observations. The resulting
calibration, with an uncertainty of about $\pm$ 20%, is then validated in
various ways, including flare line ratios from Fe XXIV and Fe XVII, emission
measure analyses of cool active region loops, and several density-dependent
line ratios.

Solar extreme ultraviolet emission - The Sun - Calibration

††journal: ApJ

##  1 Introduction

The Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) (Culhane et al.,
2007) has observed the solar corona in two wavelength bands regularly since
2006. These wavebands are commonly referred to as the shortwave (SW, 170–211
Å) and longwave (LW, 242–292 Å) channels. An accurate EIS relative calibration
is necessary e.g. to measure electron densities (see, e.g. Young et al.,
2009), to obtain estimates of emission measures (see, e.g. Warren et al.,
2011), to measure electron temperatures and test for the presence of non-
Maxwellian electron distributions via line ratios (see, e.g. the Del Zanna &
Mason, 2018, review), and for estimates of the coronal magnetic fields (see,
e.g. Li et al., 2016). An accurate absolute calibration is necessary for e.g.
a meaningful comparison with other instruments such as IRIS (Del Zanna et al.,
2022).

One way to monitor the in-flight degradation is to measure well-known
intensity ratios of lines that are insensitive to variations of densities and
temperatures and compare them to expected values. We can rely on the accuracy
of the atomic data for the strongest lines, after a series of scattering
calculations and benchmark studies have dramatically improved the EIS spectral
region. Significant improvements for the iron coronal lines observed by EIS
came with the atomic data in CHIANTI version 8 (Del Zanna et al., 2015), with
a few updates included in CHIANTI v.10 (Del Zanna et al., 2020). Typically,
there is agreement between well-calibrated radiances of strong lines and the
predicted ones within 10% or so.

One method to obtain the relative calibration is to use only spectral lines
from the same ion, while another one is to use lines from ions formed at
similar temperatures. Clearly, the first method is more robust as does not
depend significantly on the plasma conditions and on uncertainties in the
ionization fractions. This was used by Del Zanna (2013a), where a significant
revision of the ground calibration was presented. In addition, a time-
dependent decrease in the sensitivty of the LW channel was introduced,
increasing the calibrated intensities of the LW lines by nearly a factor of
two for data after 2008. Only data from 2006 until Sept 2012 were analysed.
Still, deviations in several line ratios were present, indicating the need for
wavelength-dependent corrections within each EIS channel.

Such corrections were introduced by Warren et al. (2014), where observations
of coronal lines during the 2006-2014 period were analysed. In this case, the
second method was adopted: off-limb quiet Sun (QS) observations were selected,
and assuming isothermality, the emission measure loci method was used to
enforce agreement between observed and predicted intensities using a range of
ions. This was repeated for several dates, to obtain a time- and wavelength-
dependent revision of the ground calibration.

In the present paper, we extend our previous two studies in several ways.
First, we analyse a wide range of observations covering the entire period
until 2022, of the quiet Sun and active regions (AR), both on-disk and off-
limb. Second, we relax the isothermal assumption and perform an emission
measure analysis on off-limb QS to obtain a relative calibration for a sample
of dates. Third, we extend the line ratio analysis of Del Zanna (2013a),
including well-known ratios in QS, AR and perform an automatic best-fitting
method to obtain the relative calibration amongst all wavelenghts. Fourth, we
constrain the absolute EIS calibration by comparing SW data to Solar Dynamics
Observatory (SDO) Atmospheric Imaging Assembly (AIA, Lemen et al. 2012) 193 Å
observations from 2010. Finally, we have run several checks that the
calibration provides good agreement within $\pm$20% for a sample of flare
observations, analysing Fe xxiv and Fe xvii lines, for cool lines that are
present in AR loops, and for the density-sensitive lines.

Section 2 outlines the methodology adopted, while Section 3 describes the
associated selection of the observations and data analysis. Section 4
describes a selection of the observations analysed here, while Section 5 draws
the conclusions. An Appendix provides a few more examples among the data
analysed.

##  2 Methods

The results of our previous studies, and a preliminary analysis of further
observations, clearly indicated strong wavelength-dependent variations in the
EIS responsivity. The line ratio analysis adopted for EIS by Del Zanna (2013a)
did not sufficiently sample the entire spectral region, considering separately
the coronal 1–2 MK lines visible in the QS and the hotter 2–3 MK lines only
visible in AR spectra. The additional step was to perform a DEM analysis.

###  2.1 DEM analysis on near-isothermal spectra

We adopted the method of selecting first off-limb QS observations, far enough
from the limb to reduce the blending of cool lines, but close enough to retain
enough counts. The advantage is that the plasma is nearly isothermal and
isodensity in these cases. This is an extension of the method used by Warren
et al. (2014), as we relax the isothermality assumption and perform a
differential emission measure (DEM) analysis. This method is more reliable
than the line ratio method, as several line ratios, especially those involving
lines far apart in wavelength, are somewhat temperature-dependent. Indeed
several ratios of lines from the same ion have now been identified and can be
used to measure the electron temperature (cf. Del Zanna & Mason, 2018, and
references therein).

The strongest lines in these off-limb spectra are from Fe IX–Fe XIII and Si X.
First, we estimate the average electron density from the Si X 258 vs. 261 Å
ratio. The Fe XIII 202.0, 203.8 Å and other line ratios have also been
considered, but the Si X was deemed the best case for these QS observations as
these lines are close in wavelength and the uncertainty in the relative
calibration does not affect much the results. We then calculate the $G(T)$ of
all the lines possibly contributing to the observed EIS lines, assuming a
constant density. We then perform a DEM analysis using a modified version of
the CHIANTI v.10 DEM method, which defines the DEM as a spline function, and
uses a nonlinear, least squares levenberg—marquardt fitting algorithm (MPFIT,
Markwardt 2009).

We started with calibrated intensities using the ground calibration and aimed
to obtain a correction to it, by defining a set of spline nodes for the
corrections across the EIS spectral range, most of which are located where the
strong lines are. The corrections were adjusted for each observation to obtain
a good agreement between observed and predicted intensities. The DEM was
obtained from a minimal list of lines from iron.

We then checked that the calibration obtained in this way produced good
agreement between predicted and measured intensities of a few cooler lines
formed below 1 MK. We selected a few AR loop regions, where the signal from
the hotter lines was reduced, and performed a DEM analysis. Also in this case
it is well known that the plasma distribution is nearly isothermal, which
simplifies the modelling.

Clearly, we cannot expect for all lines agreement to say 10%, as departures
from the isodensity case, optical depth and other effects can affect the
results. Also, the atomic data for different ions do not have the same
accuracy. However, what is important is the fact that those lines we have
selected, for which good agreement between observed and predicted radiances is
present, should have the same agreement regardless of the time of the
observation.

###  2.2 Line ratios

The DEM analysis provides wavelength-dependent corrections to the ground
calibration for a set of dates. Unfortunately, however, the DEM analysis is
time consuming and it is not feasible to apply this method to all EIS
observations. To obtain a correction for any given date we fit the effective
areas using a list of 39 line intensity ratios that are largely density-
insensitive at typical AR and QS temperatures. The chosen ratios are listed in
Table 4.

The general fitting methodology is as follows. First, we select a dataset of
79 AR and 88 QS observations that are relatively quiet and free of transient
features. This dataset is an extension of the observations considered in Del
Zanna (2013a). Next, we use the DEM analysis as anchor points and perform
linear interpolation to estimate the EIS effective area curve at each
observation time and compute the line ratios. Next, we produce a combined set
of measured AR and QS line ratios by averaging, separately, all AR and QS
observations within a six-month window and then concatenating the two lists
together. Then, we fit the EIS effective area curve using MPFIT such that the
relative errors of the line ratios are minimized when compared to the
theoretical values. As an additional constraint, we also simultaneously
minimize the relative ratios of select pairs of density-sensitive line ratios
for Fe XII, Fe XIII, Fe XIV, & Si X. Since only the relative ratio of each
pair of density-sensitive ratios is used in the minimization, the actual
density value computed from each individual line ratio can be ignored.

###  2.3 Emissivity ratios

As EIS data are often used to measure electron densities via line ratios, we
have included various checks to make sure that the results have some
consistency. Generally, one expects densities obtained by ions formed at
similar temperatures to be similar. Also, that densities obtained from lines
within the same ion are consistent, although in principle some differences
could occur if the plasma is strongly non-uniformly distributed. Significant
discrepancies within the Fe XII lines and in the densities obtained by Fe XII
and Fe XIII have been reported in the literature, see e.g. Young et al.
(2009).

One way to assess at once all the line ratios within an ion is to plot the
emissivity ratios (Del Zanna et al., 2004), which are obtained by dividing the
observed intensity $I_{\rm ob}$ of a line by its emissivity

$F_{ji}={I_{\rm ob}\;N_{\rm e}\;C\over N_{j}(N_{\rm e},T_{\rm
e})\;A_{ji}}\quad,$ (1)

calculated at a fixed electron temperature $T_{\rm e}$ and plotted as a
function of the density $N_{\rm e}$ ($N_{j}$ is the population of the upper
state, and $A_{ji}$ the transition rate for spontaneous emission). This method
works if the lines have a similar temperature dependence. If the plasma is
uniformly distributed along the line of sight, the curves should form a
crossing, which indicates the averaged density. The scaling constant $C$ is
arbitrarily chosen so that the crossing occurs at a value around 1.

We have applied the emissivity ratios to selected observations of Fe XII, Fe
XIII, and Si X over the years. As these ions are formed at similar
temperatures, we expect the densities to be similar. When the emissivities of
the lines are independent of density, as in the case of the Fe XVII lines, the
emissivity ratios are plotted as a function of temperature.

###  2.4 Opacity in coronal lines and other effects

The strongest EIS SW lines in the quiet Sun are three decays to the ground
state, from 4P states, at 192.4, 193.5, and 195.1 Å. The latter line is a
self-blend with a weak density-sensitive transition (Del Zanna & Mason, 2005),
which only contributes a few percent for very high densities. The intensity
ratios of the 192.4, 193.5, and 195.1 Å lines are not sensitive to density or
temperature.

An analysis of hundreds of EIS observations of different features, on-disk,
off-limb, with different exposures, slit combinations found several anomalies
in the 192.4, 193.5, and 195.1 Å lines (Del Zanna et al., 2019). The main ones
affect the instrumental widths of the 193.5, and 195.1 Å lines, which are
anomalous, and reduced intensities of the same lines (compared to the weaker
192.4 Å), in all on-disk active region and many off-limb obseervations. The
195 Å line is typically weaker than expected by 30–40 %. Note that the
intensity of the 195.1 Å line should actually increase in active region
observations, due to the presence of the above-mentioned self-blend, and not
decrease. The only explanation found for the anomalous ratios of these lines
was that optical depth effects are ubiquitous.

The intensity ratios of the 192.4, 193.5, and 195.1 Å lines in on-disk QS
observations are stable and have been used to constrain the relative
calibration between these wavelengths. There are a few other strong decays to
the ground states of other ions, with large oscillator strengths, however
establishing opacity in these other cases is non-trivial. For this reasons, we
rely more on the line ratios of the on-disk QS observations to assess the
validity of our revised calibration.

We have also preferred active region observations off-limb, and selected areas
away from the bright moss regions, to reduce possible effects in some line
ratios due to non-Maxwellian electron distributions (NMED). In fact, some
evidence based on EIS and IRIS observations have indicated that NMED are
present in active regions (Lörinčík et al., 2020; Del Zanna et al., 2022).

###  2.5 Absolute calibration

Obtaining an absolute calibration is notoriously difficult. Del Zanna (2013a)
noted that using the ground calibration, where a few wavelengths were
calibrated against laboratory standards, the radiances of the SW lines in the
QS were close to previously measured values, for observations in 2006-2007.
This indicated that the ground calibration was relatively accurate for the SW
channel. One problem with that comparison was the paucity of previous radiance
observations, andsignificant solar variability. Also, most previous
measurements were of the Sun as a star, and the irradiances had to be
converted to radiances.

Another indication that the SW ground calibration was correct in 2010 came
with direct comparisons of EIS SW vs. SDO AIA 193 Å observations, as e.g.
described in Del Zanna et al. (2011); Del Zanna (2013b). As the SW observes
the main wavelengths contributing that AIA band, it is in principle
straightforward to cross-calibrate the entire SW channel against AIA, after
taking into account the different spatio-temporal resolutions, and carefully
removing the EIS bias. The AIA 193 Å calibration was checked summing the
signal from the full Sun and comparing it against the predicted values from
the SDO EVE irradiances.

In turn, the EVE calibration relies on a comparison with a few sounding rocket
flights and adjustments using line ratios, following the methods adopted for
EIS (Del Zanna, 2013a). The prototype EVE flown on the sounding rocket flights
is regularly calibrated on the ground. The absolute calibration of the EVE
prototype is deemed accurate to within 20%, although detailed comparisons
carried out on the first flight in 2008 showed larger discrepancies (40%) for
some among the strongest lines (Del Zanna & Andretta, 2015; Del Zanna, 2019).
Calibration flights were obtained in 2011, 2012, 2013, 2018, 2021 plus a
recent one in 2023.

The failure of EVE MEGS-A in 2014 meant that no direct AIA/EVE cross-
calibrations could be carried out after that date. After 2014, the only useful
cross-calibration EVE sounding rockets were flown in 2018, 2021, and 2023. The
decrease in the sensitivity of the AIA 193 Å band has been linearly
interpolated between 2014 and 2018, which brings some additional uncertainty.
The calibration of the recent flights is still ongoing.

Any cross-caibration is never straightforward, especially when considering
broad-band observations such as the AIA ones, as a wavelength-dependent
degradation would affect the results. Such degradation is very common in
space, and indeed has been measured by EVE using different filters.
Fortunately, the overall count rates in the AIA 193 Å band only show a
decrease of about 10% over the first four years, when compared to EVE data.
This indicates moderate degradation, and confirms that this band is usable for
the EIS calibration.

Here, we used a set of co-temporal and co-spatial EIS/AIA observations to
constrain the EIS SW overall absolute calibration, adopting our revised time-
and wavelength-dependent EIS calibration. We used the modelled AIA degradation
as available in SolarSoft, with the option of the normalisation with SDO EVE
(keyword evenorm). We also checked this AIA calibration against a few
simultaneous SDO EVE observations, using the latest EVE calibration, finding
agreement to within a few percent. After the fitting the new effective area
curves using the method described in section 2.2, we scale the absolute values
of both EIS channels such that the total integrated effective area in the fit
SW channel matches that of ground calibrated SW channel after correcting for
the observed declining trend of the EIS / AIA 193 Å ratio after 2010. No
scaling was applied to fit effective areas before 2010.

##  3 Data analysis and selection of the observations

The EIS data used to obtain the relative calibration were processed with
custom-written software (see, e.g. Del Zanna et al., 2011). The hot, warm and
dusty pixels are flagged as missing, following the database available via
SolarSoft. Unfortunately, the number of residual warm pixels not flagged has
increased significantly in data during the past few years. The location of the
residual warm pixels is also variable. We have tried to avoid the most
affected regions in each EIS raster, selecting areas with visual inspection.
However, the weakest lines after 2018 are significantly compromised by the
presence of these warm pixels, which have the effect of increasing their
intensities.

The pixels affected by particle events are also flagged as ‘missing’. We used
the routine new_spike. All the missing pixels are then replaced with
interpolated values with a series of interpolations along different
directions. The exposures are then visually inspected.

The full spectral atlases are rotated to remove the slant in the spectra, and
the two SW and LW channels aligned, taking into account the different
displacements over time.

As the dark frames (bias) are extremely variable and unknown, a base minimum
value is removed from each exposure. Total data numbers (DN) in the lines are
obtained with Gaussian fitting and a polynomial background. The background and
line fitting is obtained over different spectral ranges. We note that the bias
is very difficult to estimate in the central part of the SW channel. Different
choices for the background can affect the weakest lines by a few percent. EIS
saturation is near 16000 DN, however we found indications of some non-linear
effects for lower values (Del Zanna et al., 2019), so we have avoided areas
near saturation.

##  4 Results

###  4.1 QS off-limb DEM analysis

Table 1 lists the selection of coronal lines and the results of the DEM for
the QS off-limb observation on 11 Mar 2007. Only a few lines from iron, as
listed in the Table, were used for the DEM, so the results are independent of
chemical abundance issues. The resulting DEM is shown in Fig. 1. The points
for all the coronal lines are plotted at the temperature $T_{\rm max}$ where
the line contribution function $G(T)$ has a maximum. In the ordinate, we plot
the ratio of the theoretical vs. the observed intensity multiplied by the DEM
value at that temperature, to provide a visual indication of which main lines
constrain the DEM, and how close the predicted radiances are to the observed
ones. The peak of the DEM is close to log $T$ [K] = 6.15, typical of the QS
near the limb, but the distribution is not strictly isothermal. Nevertheless,
most of the strongest lines are formed at this temperature, which makes the
comparison between lines from different ions much easier. This can be seen in
Table 1 where $T_{\rm max}$, as well as the effective temperature $T_{\rm
eff}$:

$T_{\rm eff}=\int G{\left({T}\right)}~{}DEM{\left({T}\right)}~{}T~{}dT/{\int
G{\left({T}\right)}~{}DEM{\left({T}\right)}~{}dT}\quad,$ (2)

are listed. $T_{\rm eff}$ is an average temperature more indicative of where a
line is formed. The Table also shows the total counts in each line and the
calibrated radiance obtained with the present calibration. $R$ is the ratio
between the predicted and observed radiances. We can see that generally all
lines are well reproduced within $\pm$15%, but examining lines from the same
ion, relative differences are generally within $\pm$5%.

Also note that the list includes lines that are strongly density dependent,
indicating that the isodensity approximation is relatively accurate. To
calculate the line emissivities we used a constant electron density of
2$\times$108 cm-3. The few Si X lines in the LW channel are also very useful
to constrain the LW sensitivity. Typically, the silicon abundance variations
are in line with those of iron, so again the results are virtually independent
of the chemical abundances.

A few of the extremely weak lines, with total data numbers below 100 are not
well reproduced. That is of no concern. The intensity ratios of the 192.4,
193.5, and 195.1 Å lines indicate some opacity effects.

Figure 1: DEM for the QS off-limb on 11 Mar 2007. The points are plotted at the temperature $T_{\rm max}$, and at the theoretical vs. the observed intensity ratio multiplied by the DEM value.  Table 1: QS off-limb observation on 11 Mar 2007 (90 s, 1″ slit). $\lambda_{\rm obs}$ and $\lambda_{\rm exp}$ (Å) are the observed and CHIANTI wavelengths, DN are total counts, $I_{\rm obs}$ is the radiance (phot cm-2 s-1 arc-second-2). $T_{\rm max}$ and $T_{\rm eff}$ are the maximum and effective temperature (log values, in K; see text), $R$ the ratio between predicted and observed radiances, and $r$ the fractional contribution to the blend. The lines used for the DEM have a * while those density-dependent have a dd. $\lambda_{\rm obs}$ | DN | $I_{\rm obs}$ |  log $T_{\rm max}$ |  log $T_{\rm eff}$ | $R$ | Ion | $\lambda_{\rm exp}$ | $r$
---|---|---|---|---|---|---|---|---
194.66 | 90 | 1.2 | 5.72 | 6.08 | 0.72 |  Fe viii | 194.661 | 0.92
185.22 | 61 | 4.0 | 5.73 | 6.08 | 1.02 |  Fe viii | 185.213 | 0.94
* 186.60 | 70 | 3.3 | 5.73 | 6.08 | 1.00 |  Fe viii | 186.598 | 0.83
189.94 | 155 | 3.9 | 5.94 | 6.12 | 0.91 |  Fe ix | 189.935 | 0.95
188.49 | 247 | 8.2 | 5.95 | 6.12 | 0.93 |  Fe ix | 188.493 | 0.89
* 197.85 | 268 | 4.6 | 5.96 | 6.13 | 0.91 |  Fe ix | 197.854 | 0.93
257.26 | 464 | 54.7 | 6.04 | 6.14 | 0.89 |  Fe x | 257.259 | 0.21
|  |  |  |  |  |  Fe x | 257.263 | 0.76
177.24 | 87 | 101.1 | 6.05 | 6.14 | 1.05 |  Fe x | 177.240 | 0.97
174.53 | 53 | 179.2 | 6.05 | 6.14 | 1.03 |  Fe x | 174.531 | 0.98
* 184.54 | 580 | 45.4 | 6.05 | 6.14 | 0.90 |  Fe x | 184.537 | 0.96
dd 190.04 | 728 | 18.2 | 6.06 | 6.15 | 1.03 |  Fe xii | 190.040 | 0.17
|  |  |  |  |  |  Fe x | 190.037 | 0.71
257.55 | 142 | 16.4 | 6.12 | 6.15 | 1.15 |  Fe xi | 257.554 | 0.70
|  |  |  |  |  |  Fe xi | 257.547 | 0.26
256.92 | 233 | 28.2 | 6.12 | 6.15 | 0.86 |  Fe xi | 256.919 | 0.91
dd 182.17 | 178 | 30.0 | 6.13 | 6.16 | 1.02 |  Fe xi | 182.167 | 0.97
188.30 | 1920 | 66.1 | 6.13 | 6.16 | 1.07 |  Fe xi | 188.299 | 0.97
188.22 | 3110 | 108.8 | 6.13 | 6.16 | 1.06 |  Fe xi | 188.216 | 0.97
* 192.81 | 1440 | 23.7 | 6.13 | 6.16 | 1.05 |  Fe xi | 192.813 | 0.96
180.40 | 608 | 194.2 | 6.13 | 6.16 | 1.19 |  Fe xi | 180.401 | 0.97
dd 202.71 | 141 | 9.3 | 6.13 | 6.16 | 1.14 |  Fe xi | 202.705 | 0.94
253.79 | 72 | 11.3 | 6.15 | 6.16 | 0.90 |  Si x | 253.790 | 0.97
dd 258.37 | 536 | 58.7 | 6.15 | 6.16 | 0.90 |  Si x | 258.374 | 0.97
dd 271.99 | 475 | 30.4 | 6.15 | 6.16 | 0.89 |  Si x | 271.992 | 0.97
dd 261.06 | 375 | 34.6 | 6.15 | 6.16 | 0.90 |  Si x | 261.056 | 0.98
dd 277.27 | 273 | 23.5 | 6.15 | 6.16 | 0.89 |  Si x | 277.264 | 0.98
dd 256.40 | 435 | 54.8 | 6.16 | 6.16 | 1.07 |  Si x | 256.377 | 0.63
|  |  |  |  |  |  Fe xii | 256.410 | 0.18
dd 196.64 | 491 | 7.4 | 6.19 | 6.16 | 1.17 |  Fe xii | 196.640 | 0.93
dd 186.88 | 610 | 27.3 | 6.19 | 6.16 | 1.09 |  Fe xii | 186.854 | 0.16
|  |  |  |  |  |  Fe xii | 186.887 | 0.77
dd 203.73 | 132 | 12.3 | 6.19 | 6.17 | 0.79 |  Fe xii | 203.728 | 0.96
193.51 | 6640 | 99.5 | 6.19 | 6.17 | 1.23 |  Fe xii | 193.509 | 0.95
* 192.39 | 2860 | 50.5 | 6.19 | 6.17 | 1.12 |  Fe xii | 192.394 | 0.96
195.12 | 10300 | 136.0 | 6.19 | 6.17 | 1.31 |  Fe xii | 195.119 | 0.97
dd 196.52 | 170 | 2.5 | 6.24 | 6.17 | 0.99 |  Fe xiii | 196.525 | 0.89
dd 200.02 | 303 | 7.6 | 6.24 | 6.17 | 0.77 |  Fe xiii | 200.021 | 0.94
dd 261.73 | 40 | 3.6 | 6.25 | 6.18 | 1.10 |  Fe xiii | 261.743 | 0.97
dd 203.83 | 243 | 23.3 | 6.25 | 6.18 | 1.12 |  Fe xiii | 203.795 | 0.28
|  |  |  |  |  |  Fe xiii | 203.826 | 0.62
dd 246.21 | 50 | 15.6 | 6.25 | 6.18 | 1.03 |  Fe xiii | 246.209 | 0.95
* 251.95 | 144 | 26.7 | 6.25 | 6.18 | 1.13 |  Fe xiii | 251.952 | 0.97
dd 204.94 | 57 | 7.4 | 6.25 | 6.18 | 0.88 |  Fe xiii | 204.942 | 0.96
209.92 | 51 | 18.6 | 6.25 | 6.18 | 0.97 |  Fe xiii | 209.916 | 0.96
* 202.04 | 2040 | 103.0 | 6.25 | 6.18 | 0.96 |  Fe xiii | 202.044 | 0.97
dd 264.79 | 296 | 24.2 | 6.29 | 6.18 | 0.89 |  Fe xiv | 264.789 | 0.67
|  |  |  |  |  |  Fe xi | 264.772 | 0.30
* 274.20 | 349 | 24.2 | 6.29 | 6.19 | 0.96 |  Fe xiv | 274.204 | 0.95
252.20 | 19 | 3.5 | 6.29 | 6.19 | 1.01 |  Fe xiv | 252.200 | 0.94
dd 257.40 | 55 | 6.5 | 6.29 | 6.19 | 1.05 |  Fe xiv | 257.394 | 0.96
dd 270.52 | 128 | 9.4 | 6.29 | 6.19 | 1.06 |  Fe xiv | 270.521 | 0.97
* 211.32 | 80 | 37.1 | 6.29 | 6.19 | 0.85 |  Fe xiv | 211.317 | 0.96
* 284.16 | 169 | 31.3 | 6.34 | 6.20 | 1.00 |  Fe xv | 284.163 | 0.96

The other observations were processed in a similar way, and the results are
provided in the Appendix. Generally, the consistency between observed and
predicted radiances is the same, indicating that for those observations, the
accuracy of the relative sensitivity at specific wavelengths is within
$\pm$15%. We used the set of effective areas obtained in this way as a
baseline when using the line ratios as shown below.

###  4.2 On-disk AR loop DEM analysis

Several low-$T$ lines become prominent in AR loops, and they are useful to
cross-check the relative calibration at wavelengths different than those of
the coronal lines. AR loop legs are nearly isodensity and isothermal (cf Del
Zanna & Mason, 2018, and references therein) so they are also good sources for
the cross-calibration.

As we are not interested in the coronal lines in this case, only the cooler
lines are considered to check the relative calibration. As multiple isothermal
structures are present in AR cores (cf Del Zanna, 2013b), obtaining a DEM
which reproduces well all lines is challenging, compared to the QS off-limb
case. Nevertheless, as we are primarily concerned to check the relative
agreement between lines from the same ion or lines with similar effective
temperatures, an accurate estimate of the DEM is not necessary.

We have performed the analysis on a few cool loops at different dates, and
found general consistency using the effective areas obtained with the previous
method. One example is provided in the Appendix.

###  4.3 Line radiances

Figure 2: Top: Hinode EIS quiet Sun count rates (DN/s) in two cooler SW lines.
Bottom: radiances with the present calibration.

The large solar variability precludes the use of QS radiances for the EIS
calibration, as carried out for the SOHO CDS, as only two low-temperature
lines are available, the He II 256.3 Å and the O V 192.9 Å. The former is
blended with several coronal lines, and the latter is weak and hard to
measure. However, several transition-region lines are expected to show a small
variation with the solar cycle, and should have similar radiances during the
2008 and 2019 minima. Fig. 2 (top) shows the count rates in two cool SW lines.
It is clear that there is a decrease in the signal, especially after 2010.
Fig. 2 (bottom) shows the corrected radiances with the present calibration.

Figure 3: Top: Hinode EIS quiet Sun count rates in two cooler LW lines.
Bottom: radiances with the present calibration.

Fig. 3 (top) shows the count rates in the He II 256.3 Å, which has been
deblended from its coronal contributions, and a weak Mg VII line. The signal
in the He II line during 2007 was relatively constant, but then had a
significant drop in 2010, with a subsequent constant behaviour. On the other
hand, all the lines at longer wavelengths show a very different behaviour: a
nearly constant one until 2010, followed by a drop until 2016. This is a clear
indication of a very different decrease in sensitivity at different
wavelengths, which is difficult to explain and account for.

###  4.4 Line ratios

Figure 4: Example fit effective area curves for an active region observed on
2011-07-26. Figure 5: Example fit effective area curves for an active region
observed later in the mission on 2019-06-28. Figure 6: Relative line ratios
observed in AR over time. Ratios computed using the pre-flight calibration are
shown as black diamonds and ratios computed from the new fits are shown as
blue crosses. Figure 7: Relative line ratios observed in QS over time. Ratios
computed using the pre-flight calibration are shown as black diamonds and
ratios computed from the new fits are shown as blue crosses.

We extended the analysis of the dataset considered in Del Zanna (2013a), i.e.
a set of on-disk QS regions, and a set of AR observations, mostly off-limb to
reduce the contamination of the coronal lines from the cooler lines and
opacity effects. For each observation, suitable regions were selected to
obtain averaged spectra, and all lines fitted.

We selected several known ratios which are expected to be rather constant.
They are listed in the Appendix. Most of the ratios are the same used in Del
Zanna (2013a). Only a limited number of line ratios are well measured in on-
disk QS regions. Lines formed above 1.5 MK such as Fe XIII are only well
observed in AR observations.

Figures 4 and 5 show example fit effective areas for two different ARs
observed, respectively, in 2011 and 2019. The left column of each figure
contain the SW effective areas while the right column contain the LW. The top
two panels in both columns show the relative line ratios of the pre-flight
(top) and fit (middle) effective area profiles. A relative ratio of 1
indicates a perfect match with the theoretical line ratio. In both AR, the fit
profiles greatly improve the relative ratios. Compared to the pre-flight
profiles, the fit effective areas exhibit finer-scaled variations and have
notable "shoulders" in both the SW (around 197 – 200 Å) and LW ( 265 – 269 Å)
bands. The LW profiles shows more significant degradation over time than the
SW profiles. It is worth noting here that the shape of the fit effective area
profiles is sensitive to the number and spacing of the spline knots using for
the fitting process. More knots allow for a better fit to each individual time
period but also results in "wavy" profiles with more local maxima and minima
and year-to-year variation of shapes. On the other hand, fewer spline knots
results in smoother profiles but lower quality fits. Since we do not know the
primary cause of the decline in EIS sensitivity, we do not have any reason to
bias the fit towards wavy or smooth profiles. Therefore, after experimenting
with a variety of spline knot spacings, we settled on using an average spacing
of 5 Å between spline knots in both the SW and LW bands, with one knot removed
from 170 Å, in the tail of the SW profile, and two extra knots added at 192.5
and 197.5 Å, near the SW peak. This resulted in profiles that were moderately
smooth, yet still fit the observed line ratios well. Altogether, we used 20
spine knots to perform the fitting, which is a moderate increase over the 14
spline knots used for the fitting in Warren et al. (2014). The spline knots
used for the preliminary DEM analysis of the off-limb data are slightly more
irregular (cf. the Appendix).

Figures 6 and 7 compare selected line ratios computed over time using the pre-
flight (black diamonds) and fit (blue crosses) effective areas. The ratios
were normalized by their respective theoretical values. In both figures, the
left two columns contain lines in the SW channel, the right two columns show
ratios in the LW channel, and the middle column contains cross-channel ratios.
Most of the fit line ratios show dramatic improvement over the pre-flight
ratios, with new values falling within 20% of the theoretical values. However,
a few ratios show little to no improvement.

###  4.5 Flare observations: Fe XXIV and Fe XVII

Figure 8: The Fe XXIV 192/255 Å ratio relative to theory as a function of time
using the pre-flight calibration and the present time-dependant effective
areas.

Figure 9: Emissivity ratio curves obtained with the present calibration for
the main Fe xvii EUV transitions observed by Hinode EIS during two M-class
flares, on 2012 March 9 and 2015 June 21. Iob is the calibrated measured
intensity in photons cm-2 s-1 arcsec-2.

A few lines become prominent in flare observations and offer the possibility
to check the relative calibration at different wavelengths. As only a few
flares have been observed by EIS with a sufficient number of lines, the check
is rather limited. The best ions are Fe XXIV and Fe XVII.

The Fe XXIV 192/255 Å is a good ratio to validate the SW/LW cross-calibration,
as it does not depend on density or temperature, and could only be affected by
H, He absorption or opacity effects. The lines are usually blended with
several transitions ( e.g. Del Zanna, 2008), but for strong flares the Fe XXIV
is dominant. We have computed the Fe XXIV 192 and 255 Å intensities for all
available EIS `FlareResponse` and `HH_Flare` rasters and manually selected
observations where the flare produced more than 50 pixels with statistically
significant intensities, but were not dominated by pixels with saturation or
diffracted signal. As is seen in Figure 8, when using the ground calibration
the ratio departs by more than 50% from the expected value. The few data
points between 2015 and 2018 also indicate a trend for the ratio to decrease.
Using the updated calibration described in this paper brings the ratios to
agreement with theory to within $\pm$20%.

As reviewed by Del Zanna & Ishikawa (2009), Fe XVII produces several lines in
the EIS channels. The 204.6 and 254.9 Å form a branching ratio, for which
atomic data are very accurate, and therefore are useful to validate the SW/LW
cross-calibration. Many other Fe XVII lines are available across the LW
channel, although they become usable and unblended only in larger flares. The
line ratios do not have any density dependence and negligible temperature
dependence, hence are excellent for the calibration.

Figure 9 shows the emissivity ratio curves relative to the main Fe xvii lines
observed by Hinode EIS on two M2-class flares. With the exception of the very
weak lines at 259.59 and 288.95 Å, all the line emissivities agree within
$\pm$ 20%.

###  4.6 Absolute calibration after 2010: EIS vs. AIA

Figure 10: The ratio of EIS 193 to AIA 193 Å as a function of time using the
pre-flight calibration (top panel) and the new, time-dependant effective areas
(bottom panel). The EIS intensities have been convolved with the AIA 193
effective area to compute the expected AIA 193 count rates.

The absolute values for the EIS responsivity have been constrained by a direct
comparison between the EIS SW and the AIA 193 Å count rates using several
observations after 2010. We gave preference to active region observations to
have a better signal in the EIS spectra. The ‘bias’ in the EIS spectra has
been fitted pixel-by-pixel on the spectra in DN. To predict the AIA DN/s we
have used the AIA effective areas obtained using the /evenorm and /time
dependent keywords. The AIA data have been resampled to the temporal and
spatial resolution of EIS. On a pixel-by-pixel basis, there is generally a
large scatter of values, partly due to the different point spread functions
(PSF) of the instruments, and the lack of exact simultaneity in the
observations. Nevertheless, averaging over spatial areas reduces the scatter,
so the relative calibration can be estimated with only a few percent accuracy.
More details are provided in the Appendix.

The averaged ratio between predicted and measured AIA DN obtained using the
EIS ground calibration indicates a degradation of nearly a factor of two, as
shown in Fig. 10 (top). This is clearly due to a decrease in the sensitivity
of the EIS SW channel with time.

To obtain the EIS absolute calibration, we have first used the revised EIS SW
relative calibration obtained with the previous methods to obtain calibrated
units, to then convert them to predicted AIA counts. We have then applied
corrections factors to the grid of selected dates, to obtain a better match
with AIA. The results are shown in Fig. 10 (bottom).

Figure 11: 2D histograms of the effective areas in the shortwave (top panel)
and longwave (second panel) channels. Also shown are the effective areas at
selected wavelengths near the peak and and tails of the shortwave (third
panel) and longwave (fourth panel) channels.

###  4.7 Absolute calibration before 2010

Establishing the absolute calibration before 2010 is difficult. We would
normally expect the sensitivity at all wavelengths to decrease with time,
hence the effective areas at the beginning of the mission should be higher
than in 2010. However, many published studies indicated that the ground
calibration in the SW channel was reasonable for the 2007 data, except for the
shorter wavelengths, as shown in Del Zanna (2013a). Wang et al. (2011)
performed a direct comparison between EIS SW and EUNIS quiet Sun (QS)
observations in 2007, finding a small (20%) decrease compared to the ground
calibration, a variation within the EUNIS calibration uncertainties.

Another way to assess the calibration is to check that the quiet Sun
calibrated radiances in low-temperature lines agree with literature values.
There is always a scatter in the radiances of the quiet Sun, but on average
they are relatively constant and largely independent of the solar cycle. In
fact, they have been used for the in-flight calibration of the SOHO CDS
instrument (cf Del Zanna & Andretta, 2015; Andretta & Del Zanna, 2014). As in
Del Zanna (2013a), we have checked that the calibrated radiances are within
20–30% the literature values, for the few lines for which measurements were
found. Furthermore, we have carried out an emission measure analysis using
averaged quiet Sun CDS and EIS radiances, to check that we have consistency
within 20%. Results will be discussed in a separate paper.

###  4.8 Effective areas

Figure 11 shows the changes in the fit effective areas over time. The top two
panels show the full 2D histograms for all wavelengths in each wave channel
and the bottom two panels contain the values at select lines near the peaks
and tails of each wave channel. The SW band (first and third panels) exhibit
relatively little change until late 2012 and then a gradual decline in
sensitivity after. In contrast, the sensitivity in the LW band (second and
fourth panels) declines much faster at first, but then appears to plateau
after 2017. Additionally, the LW band is more variable, which may indicate
that the fit in that channel is more susceptible to outliers. This complex,
channel-dependent decay in sensitivity is similar to the trends noted by
Warren et al. (2014) for the years 2007 – 2013.

##  5 Conclusions

After trying several approaches we have presented what we believe is the best
combination of methods, to provide a reasonable in-flight radiometric
calibration for EIS. Overall, it provides calibrated intensities which should
be accurate to within $\pm$20 %. The overall degradation over time in the
central parts of the two channels has been less than a factor of two over the
2006-2022 period, which is an excellent performance, one of the best of any
EUV instrument in space, and the best of any EUV spectrometer (SOHO CDS
degraded by a factor of about 2 in 13 years, see Del Zanna & Andretta 2015).
Significant degradation is however present in various spectral regions.

As we have not found any evidence for systematic wavelength-dependent
degradation, we do not have an explanation for the unusual evolution of the
effective areas. Nearly all previous EUV/UV space instruments have shown
significant degradation (see e.g. BenMoussa et al., 2013), which was usually
thought to be associated with polimerization of chemical compounds (mostly
including carbon) onto the surfaces of the front filters, caused by exposure
to the strong solar flux. Such degradation is typically wavelength-dependent
and the simple aluminium filters, used for the EUV (as for Hinode EIS), are
particularly affected. Recently, it has been found that oxidation, caused by
outgassing of water molecules, has also been causing major degradation for SDO
instruments, see e.g. Tarrio et al. (2023). It seems unlikely that there is
contamination on the EIS detector itself. Three EIS detector bakeouts were
performed (2016 February 23–26, 2017 August 8–10, and 2018 January 17–21) and
no significant changes in response have been observed (see Figure 10).

We have biased the effective areas to keep a relatively smooth behaviour over
time, associated with the degradation of the multilayers. Some wavelength
regions are not well constrained, and a more accurate relative calibration
could be obtained by analysing line ratios observed close in time to a
specific observation.

Continuous monitoring of the degradation is recommended, by running EIS
atlases in quiet Sun on-disk and off-limb regions, with exposure times of at
least 60s, and off-limb active regions, with exposures of at least 30s.

Acknowledgments

GDZ acknowledges support from STFC (UK) via the consolidated grants to the
atomic astrophysics group (AAG) at DAMTP, University of Cambridge
(ST/P000665/1. and ST/T000481/1). HPW and MJW were supported by NASA’s Hinode
program.

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##  Appendix A Extra information on QS and AR data

The QS on-disk observations, with exposure times of 60 or 120 s and the 2″
slit have been averaged spatially before fitting the lines to obtain DN/s.
Most of the observations were using the ATLAS_60 or ATLAS_120. Table 2 gives
the list of the files analysed.

Fig. 12 gives as an example three of those spectra, taken near the beginning
of the mission in 2008, in 2012, and 2017. Some of the hotter lines have a
strong variability with the solar cycle and location, but those formed at 1 MK
and below are not expected to show strong variability (see, e.g. the
discussion in Del Zanna & Andretta, 2015, related to the SOHO/CDS
calibration). The figure shows the clear decrease in the signal with time, and
the fact that the shorter and longer wavelengths of the LW channel degraded
significantly already by 2017.

Table 2: List of the quiet Sun EIS observations analysed. 20140811_032251 | 20150322_100148 | 20150523_191534 | 20150824_090730 | 20151117_030548 |
---|---|---|---|---|---
20160117_090447 | 20160322_032503 | 20160411_221723 | 20160828_104853 | 20161009_163155 |
20161119_111934 | 20161217_111122 | 20170604_110854 | 20170816_113050 | 20170914_155935 |
20171105_150928 | 20180114_130641 | 20180612_000414 | 20180808_185533 | 20180830_041726 |
20181026_133649 | 20181225_204342 | 20190227_041730 | 20190421_160905 | 20190629_034213 |
20190906_002026 | 20191019_021112 | 20191212_224436 | 20200229_150606 | 20200531_145440 |
20200701_132213 | 20200925_025943 | 20201102_071219 | 20210302_221641 | 20210312_044443 |
20210403_182040 | 20210716_024902 | 20210810_164920 | 20211013_031242 | 20211130_140230 |
20211224_021532 | 20220307_160313 | 20220601_042513 |  |  |

For the active region datasets, most of the data were from the ATLAS_30 or
ATLAS_60. Table 3 lists the EIS files analysed. Whenever available, off-limb
observations were used.

Table 3: List of the active region EIS observations analysed. 20061225_225013 | 20070118_120435 | 20070220_054028 | 20070511_105544 | 20070714_000949 |
---|---|---|---|---|---
20071114_000707 | 20080107_101448 | 20080204_104700 | 20080620_230339 | 20081217_110519 |
20090322_060630 | 20090521_180529 | 20090725_055049 | 20091025_214625 | 20100123_171532 |
20100517_135741 | 20100922_112633 | 20101109_100733 | 20110121_123757 | 20110522_103354 |
20110726_175935 | 20111022_100543 | 20111217_125856 | 20120416_124033 | 20120704_223657 |
20120830_234044 | 20130127_081649 | 20130327_021709 | 20130601_115857 | 20130915_151340 |
20131104_075110 | 20140114_122452 | 20140508_182049 | 20140718_132530 | 20141013_111316 |
20141223_102142 | 20150322_215524 | 20150615_195749 | 20151022_014109 | 20151230_182726 |
20160317_203054 | 20160530_213525 | 20160804_081348 | 20161001_182941 | 20161210_202027 |
20170208_111733 | 20170503_115341 | 20170802_130640 | 20171008_014841 | 20171202_000340 |
20180117_085140 | 20180612_032114 | 20180810_083243 | 20181006_141212 | 20181216_101341 |
20190130_234741 | 20190326_130041 | 20190615_182748 | 20190628_093832 | 20190903_111822 |
20191011_235843 | 20191224_213813 | 20200202_133341 | 20200503_112000 | 20200615_004741 |
20200806_001010 | 20201006_111549 | 20201115_214810 | 20201202_112940 | 20210228_155913 |
20210420_200014 | 20210529_151812 | 20210802_224611 | 20210903_084840 | 20211104_030841 |
20211226_120039 | 20220306_232633 | 20220428_234108 | 20220807_142340 |  |

Figure 12: Hinode EIS spectra (DN/s/1” slit) for the quiet Sun on-disk, for
three sample dates. The dashed line is the scaled ground-calibration effective
area.

##  Appendix B Selected line ratios

Table 4 lists the line ratios selected for the EIS relative calibration. The
best ones are branching ratios, as they do not depend on electron density and
have a small theoretical uncertainty, of the order of 10%. The other ratios
have a larger typical uncertainty, around 20%. We then used different ratios
for the QS and AR observations. Some ratios have some small density
sensitivity, which we list in the Table. Most ratios are useful to constrain
the relative calibration within the SW and LW, but some are also available to
check the SW/LW relative ratio.

Table 4: Line ratios used for the EIS calibration. The second and third columns show the theoretical ratios (photon units) for suitable densities for the QS and AR. The last column indicates the channel. BR indicates a branching ratio.  Line ratio (Å) | Predicted (QS) | Predicted (AR) | Notes | Det.
---|---|---|---|---
| (log Ne=8.2–8.8) | 8.5–9.5 |  |
Fe ix 189.94 / 197.85 | 1.0–1.2 | 1.1–1.5 ** |  | SW
Fe ix 188.49 / 197.85 | 2.0–2.1 | 2.0–2.5 ** |  | SW
Fe x 174.5 / 184.5 | 4.5–4.4 | 4.45–4.0 |  | SW
Fe x 177.2 / 184.5 | 2.6–2.5 | 2.58–2.35 |  | SW
Fe x 190.0 (bl) /184.5 | 0.338 |  |  | BR SW
Fe x 207.45 / 184.5 | 0.14–0.16 | 0.15–0.21 ** |  | SW
Fe x 257.3 (sbl) / 184.5 | 1.5–1.2 | 1.35–0.8 ** |  | LW/SW
Fe xi 178.1 / 182.17 | 0.274 |  | weak | BR SW
Fe xi 188.2 / 192.8 (bl) | 4.8 |  |  | BR SW
Fe xi 202.7 / 188.3 | 0.1 |  |  | BR SW
Fe xi 180.4 / 188.2 | 2.0–1.98 | 1.99–1.88 |  | SW
Fe xi 257.5 (sbl) / 188.2 | 0.17–0.19 | 0.175–0.24 ** |  | LW/SW
Fe xii 192.4 / 195.1 (sbl) | 0.315 |  |  | SW
Fe xii 193.5 / 195.1 (sbl) | 0.67 |  |  | SW
Fe xii 186.9 (sbl) / 196.6 (bl) | 3.45–3.6 | 3.5–4.1 ** |  | SW
Fe xiii 209.9 (bl) / 202.0 | 0.15 |  |  | BR SW
Fe xiii 204.9 (bl) / 201.1 (bl) | 0.31 |  |  | BR SW
Fe xiii 201.1 (bl) /197.4 | 5.0 |  |  | BR SW
Fe xiii 204.9 (bl) / 197.4 | 1.55 |  |  | BR SW
Fe xiii 209.6 / 200. | 0.74-0.69 | 0.69–0.71 |  | SW
Fe xiii 246.2 (bl?) / 251.9 | 0.51 |  |  | BR LW
Fe xiii 261.7 / 251.9 | 0.135-0.12 | 0.125–0.105 |  | LW
Fe xiii 261.7 / 201.1 (bl) | 0.185-0.17 | 0.17–0.18 |  | LW/SW
Fe xiii 251.9 / 201.1 (bl) | 1.35–1.45 | 1.4–1.65 ** |  | LW/SW
Fe xiii 251.9 / 204.9 | 4.6–4.9 | 4.7–5.5 ** |  | LW/SW
Fe xiv 252.2 / 264.8 | 0.23 |  |  | BR LW
Fe xiv 257.4 / 270.5 | 0.68 |  |  | BR LW
Fe xiv 289.1 / 274.2 | 0.065 |  | weak | BR LW
Fe xiv 274.2 / 211.3 | 0.71 | 0.71–0.69 |  | LW/SW
Fe xiv 270.5/ (264.7+274.2) | 0.265 | 0.265-0.255 |  | LW
Fe xvi 251 / 263 | 0.57 | 0.57 |  | LW
Fe xvi 265 / 263 | 0.098 | 0.098 |  | LW
Fe xvii 254.9 / 204.7 | 1/0.93 |  |  | BR LW/SW
Fe xxiv 255.1 / 192 | 1/1.85 |  |  | LW/SW
Si x 253.8 / 258.4 | 0.194 |  |  | BR LW
Si x 277.3 / 272. | 0.84 |  |  | BR LW
Si x 277.3 / 261.1 | 0.68 | 0.68–0.70 |  | LW
S x 257.1 (bl) / 264.2 | 0.348 | 0.348 |  | LW
S x 259.5 / 264.2 | 0.68 | 0.68 |  | LW
S xi 285.6 (sbl) / 281.4 | 0.496 |  |  | BR LW

##  Appendix C Absolute calibration after 2010: EIS vs. AIA

As a first step, the EIS data were processed with eis_prep and the pre-flight
calibration. The AIA 193 Å data were cutouts downloaded from the JSOC with an
expanded FOV relative to EIS and a cadence of 36 s. These data are processed
with aia_prep.

For each EIS exposure, the backgrond was estimated, and the spectrum convolved
with the AIA effective area (EA) calculated using the evenorm and
timedepend_date keywords, to compute the expected AIA counts. The nearest 3
AIA images were found and averaged. The averaged was then smoothed over 5
pixels (3″) and rebinned to the EIS pixel size of 1″. The predicted and
observed AIA images were then cross-correlated to find the optimal EIS
pointing, i.e. finding (aia_x, aia_y), the position of the bottom of the eis
slit derived from AIA. Since the cross correlation is done exposure by
exposure, it can be noisy, particularly if there is little structure along the
slit. We expect that the aia_y values should all be very similar and the aia_x
values to increase linearly with time due to solar rotation. A second pass is
then computed, and a mean aia_y and a linear fit to aia_x obtained.

##  Appendix D Normalized Emissivity Curves

Density-sensitive line ratios are often used in the literature to measure the
electron density. Such measurements rely on accurate atomic data and relative
radiometric calibration. As the EIS effective area has a strong wavelength
variation, any small change in the relative effective area can affect the
density measurements significantly. We have checked for a sample of dates that
the electron densities obtained from the main line ratios and ions are
reasonable, using the emissivity ratio method, described in the main part of
the paper. Fig. 13 shows one example for the main coronal lines. We expected
the ratio curves to intersect, providing a density measurements, although in
principle some departures can occur, as each transition is likely formed in a
slightly different spatial region. The curves of the strong Fe xii lines at
192.4, 193.5, 195.1 Å often show discrepancies, related to opacity effects.
The weaker transition at 192.4 Å is less affected and should be used for the
density measurements. We do not expect that densities measured by different
ions should be exactly the same, but those of the Fe xii, Fe xiii and Si x
should be consistent, as these ions are formed within similar temperatures.
The emissivity ratios in the off-limb QS regions generally show better
agreement than those in active regions, as one would expect.

Figure 13: Normalized emissivity curves for Fe XII, Fe XIII, Fe XIV, and Si X.
The left two columns show the curves computed using the pre-flight and fit
effective areas for a QS off-limb subregion observed on 2017-07-28. The right
two columns show the results for a subregion containing an AR observed on
2019-06-28.

##  Appendix E On-disk AR loop DEM analysis

As in the QS off-limb case, we have used a constant density assumption to
obtain the $G(T)$ of the lines. The temperature distributions typically have
multiple peaks, one around log $T$[K]=5.6 produced by the loop legs, and other
ones due to the background/foreground coronal plasma present in the AR core.

Table 5 lists the main lines. The most useful lines are from Fe VIII, as they
cover both SW and LW. The stronger lines are well represented within $\pm$10%.
The Fe IX lines are also useful to check the SW sensitivity, especially at the
location of the resonance line at 171.0 Å, as this line is always very weak in
any QS observation. The three LW lines from Si VII are in good agreement with
those from Fe VIII, while other lines show larger departures. The O V 192.9 vs
248.5 Å ratio is not very reliable as lines are weak and are both temperature
and density sensitive.

Table 5: Same as Table 1, but for an AR loop observation on 26 Oct 2010 $\lambda_{\rm obs}$ | DN | $I_{\rm obs}$ |  log $T_{\rm max}$ |  log $T_{\rm eff}$ | $R$ | Ion | $\lambda_{\rm exp}$ | $r$
---|---|---|---|---|---|---|---|---
192.91 | 2690 | 170.9 | 5.42 | 5.56 | 1.38 |  O v | 192.904 | 0.84
248.49 | 260 | 319.8 | 5.42 | 5.58 | 0.87 |  O v | 248.461 | 0.91
276.58 | 1210 | 296.1 | 5.50 | 5.59 | 0.74 |  Mg v | 276.579 | 0.98
246.00 | 524 | 799.5 | 5.64 | 5.67 | 0.46 |  Si vi | 246.003 | 0.98
270.39 | 3630 | 887.6 | 5.65 | 5.68 | 0.36 |  Mg vi | 270.400 | 0.12
|  |  |  |  |  |  Mg vi | 270.391 | 0.87
268.99 | 1720 | 464.9 | 5.66 | 5.68 | 0.34 |  Mg vi | 268.991 | 0.98
255.11 | 252 | 130.6 | 5.66 | 5.73 | 0.96 |  Fe viii | 255.110 | 0.99
255.35 | 391 | 197.3 | 5.67 | 5.73 | 1.03 |  Fe viii | 255.350 | 0.96
253.96 | 509 | 306.6 | 5.67 | 5.74 | 1.06 |  Fe viii | 253.956 | 0.99
195.97 | 5720 | 298.8 | 5.31 | 5.75 | 1.12 |  Fe viii | 195.972 | 0.92
207.12 | 286 | 183.7 | 5.70 | 5.76 | 0.93 |  Fe viii | 207.124 | 0.73
|  |  |  |  |  |  Fe viii | 207.124 | 0.25
197.36 | 3050 | 172.6 | 5.71 | 5.76 | 0.84 |  Fe viii | 197.362 | 0.97
194.66 | 8270 | 442.0 | 5.72 | 5.76 | 1.17 |  Fe viii | 194.661 | 0.99
186.60 | 8150 | 1573.1 | 5.73 | 5.80 | 1.03 |  Fe viii | 186.598 | 0.96
185.22 | 7630 | 2116.2 | 5.73 | 5.80 | 1.09 |  Fe viii | 185.213 | 0.97
280.74 | 849 | 304.8 | 5.79 | 5.82 | 0.64 |  Mg vii | 280.742 | 0.98
276.14 | 613 | 146.1 | 5.79 | 5.83 | 0.66 |  Mg vii | 276.154 | 0.98
275.37 | 2660 | 612.9 | 5.79 | 5.83 | 1.03 |  Si vii | 275.361 | 0.98
275.69 | 458 | 106.8 | 5.80 | 5.83 | 1.05 |  Si vii | 275.676 | 0.98
272.66 | 940 | 183.8 | 5.80 | 5.83 | 1.07 |  Si vii | 272.648 | 0.98
278.39 | 3270 | 907.6 | 5.79 | 5.83 | 0.53 |  Mg vii | 278.404 | 0.97
277.00 | 2460 | 615.3 | 5.84 | 5.87 | 0.80 |  Mg vii | 277.003 | 0.57
|  |  |  |  |  |  Si viii | 277.058 | 0.39
276.84 | 953 | 236.0 | 5.87 | 5.88 | 1.26 |  Si viii | 276.850 | 0.47
|  |  |  |  |  |  Si vii | 276.851 | 0.48
171.07 | 122 | 8739.7 | 5.93 | 5.91 | 0.92 |  Fe ix | 171.073 | 0.99
189.94 | 2450 | 250.6 | 5.94 | 5.92 | 0.94 |  Fe ix | 189.935 | 0.97
191.21 | 1770 | 150.2 | 5.94 | 5.92 | 0.69 |  Fe ix | 191.206 | 0.98
188.49 | 3240 | 432.2 | 5.94 | 5.93 | 1.00 |  Fe ix | 188.493 | 0.91
197.85 | 2760 | 162.7 | 5.96 | 5.94 | 1.01 |  Fe ix | 197.854 | 0.95
190.04 | 2370 | 239.2 | 6.05 | 6.04 | 1.07 |  Fe x | 190.037 | 0.68
|  |  |  |  |  |  Fe ix | 190.059 | 0.17

##  Appendix F Off-limb DEM analysis

Tables 6,7,8, 9,10,11, 12 show the summary results of the DEM analysis for the
main (strongest) coronal lines, in off-limb observations. Note that in the
last observation hotter active region plasma was present.

The calibrated intensities were obtained by manual adjustment of the ground
calibration effective area, using splines with nodes at 165, 171, 174.5,
177.2, 178.1, 180.4, 182.2, 184.5, 185.2, 186.9, 188.3, 190, 192.4, 192.8,
193.5, 194.7, 195.1, 196.6, 197.4, 200, 201.1, 202., 202.7, 204.9, 208, 209.9,
211.3 Å for the SW channel, and 245, 252, 255, 257, 259, 263 , 265, 268, 270,
272, 274, 277, 281, 286, 292 Å for the LW channel. These wavelengths are close
to main coronal lines. The absolute scale of the calibration was adjusted with
a preliminary cross-calibration with AIA. These effective areas were used as
initial constraint on the final effective areas, obtained by automatic fitting
the line ratios.

Table 6: Same as Table 1, but for a QS off-limb observation on 16 Oct 2010 $\lambda_{\rm obs}$ | DN | $I_{\rm obs}$ |  log $T_{\rm max}$ |  log $T_{\rm eff}$ | $R$ | Ion | $\lambda_{\rm exp}$ | $r$
---|---|---|---|---|---|---|---|---
194.66 | 238 | 6.4 | 5.72 | 6.02 | 1.27 |  Fe viii | 194.661 | 0.94
185.22 | 218 | 30.3 | 5.73 | 6.03 | 1.30 |  Fe viii | 185.213 | 0.93
186.60 | 222 | 23.0 | 5.73 | 6.04 | 1.30 |  Fe viii | 186.598 | 0.86
189.94 | 382 | 19.6 | 5.94 | 6.10 | 1.24 |  Fe ix | 189.935 | 0.97
188.49 | 728 | 52.4 | 5.95 | 6.10 | 0.97 |  Fe ix | 188.493 | 0.89
197.85 | 886 | 26.0 | 5.96 | 6.11 | 1.01 |  Fe ix | 197.854 | 0.93
257.26 | 1030 | 214.5 | 6.04 | 6.13 | 0.98 |  Fe x | 257.259 | 0.22
|  |  |  |  |  |  Fe x | 257.263 | 0.76
177.24 | 204 | 646.7 | 6.05 | 6.14 | 1.03 |  Fe x | 177.240 | 0.97
174.53 | 108 | 1101.1 | 6.05 | 6.14 | 1.07 |  Fe x | 174.531 | 0.98
184.54 | 1700 | 281.6 | 6.05 | 6.14 | 0.89 |  Fe x | 184.537 | 0.95
190.04 | 2170 | 109.3 | 6.06 | 6.15 | 1.05 |  Fe xii | 190.040 | 0.19
|  |  |  |  |  |  Fe x | 190.037 | 0.68
257.55 | 322 | 65.2 | 6.12 | 6.16 | 1.25 |  Fe xi | 257.554 | 0.69
|  |  |  |  |  |  Fe xi | 257.547 | 0.26
189.02 | 298 | 18.9 | 6.13 | 6.16 | 0.73 |  Fe xi | 188.997 | 0.95
256.92 | 492 | 104.7 | 6.12 | 6.16 | 0.97 |  Fe xi | 256.919 | 0.91
182.17 | 507 | 193.2 | 6.13 | 6.16 | 0.98 |  Fe xi | 182.167 | 0.97
192.81 | 4550 | 160.2 | 6.13 | 6.16 | 0.89 |  Fe xi | 192.813 | 0.96
188.30 | 5980 | 448.3 | 6.13 | 6.16 | 0.92 |  Fe xi | 188.299 | 0.97
181.13 | 95 | 57.3 | 6.13 | 6.16 | 1.13 |  Fe xi | 181.130 | 0.97
188.22 | 9530 | 726.2 | 6.13 | 6.16 | 0.92 |  Fe xi | 188.216 | 0.97
180.40 | 1630 | 1340.4 | 6.13 | 6.17 | 1.05 |  Fe xi | 180.401 | 0.97
180.60 | 69 | 52.7 | 6.13 | 6.17 | 0.88 |  Fe xi | 180.594 | 0.96
202.71 | 423 | 47.3 | 6.13 | 6.17 | 1.23 |  Fe xi | 202.705 | 0.92
253.79 | 167 | 51.5 | 6.15 | 6.17 | 0.93 |  Si x | 253.790 | 0.97
258.37 | 1300 | 248.6 | 6.15 | 6.17 | 0.98 |  Si x | 258.374 | 0.97
261.06 | 845 | 135.0 | 6.15 | 6.17 | 0.99 |  Si x | 261.056 | 0.98
271.99 | 1200 | 116.5 | 6.15 | 6.17 | 0.95 |  Si x | 271.992 | 0.97
277.27 | 687 | 87.2 | 6.15 | 6.17 | 0.98 |  Si x | 277.264 | 0.98
256.40 | 1030 | 229.8 | 6.16 | 6.18 | 1.18 |  Si x | 256.377 | 0.59
|  |  |  |  |  |  Fe xiii | 256.400 | 0.12
|  |  |  |  |  |  Fe xii | 256.410 | 0.18
249.39 | 114 | 65.0 | 6.19 | 6.19 | 0.86 |  Fe xii | 249.388 | 0.70
|  |  |  |  |  |  Fe xii | 249.384 | 0.23
196.64 | 1900 | 51.4 | 6.19 | 6.19 | 1.16 |  Fe xii | 196.640 | 0.93
186.88 | 2310 | 225.8 | 6.19 | 6.19 | 0.98 |  Fe xii | 186.854 | 0.16
|  |  |  |  |  |  Fe xii | 186.887 | 0.77
193.51 | 22900 | 765.5 | 6.19 | 6.19 | 1.02 |  Fe xii | 193.509 | 0.95
195.12 | 36200 | 852.8 | 6.19 | 6.19 | 1.32 |  Fe xii | 195.119 | 0.97
192.39 | 9820 | 343.6 | 6.19 | 6.19 | 1.05 |  Fe xii | 192.394 | 0.96
196.52 | 674 | 18.1 | 6.24 | 6.21 | 1.21 |  Fe xiii | 196.525 | 0.92
200.02 | 1420 | 59.2 | 6.25 | 6.21 | 0.93 |  Fe xiii | 200.021 | 0.95
261.73 | 136 | 20.9 | 6.25 | 6.22 | 1.17 |  Fe xiii | 261.743 | 0.97
203.83 | 1430 | 229.6 | 6.25 | 6.22 | 1.06 |  Fe xiii | 203.795 | 0.28
|  |  |  |  |  |  Fe xiii | 203.826 | 0.63
246.21 | 142 | 106.4 | 6.25 | 6.22 | 1.02 |  Fe xiii | 246.209 | 0.95
251.95 | 483 | 193.3 | 6.25 | 6.22 | 1.03 |  Fe xiii | 251.952 | 0.97
204.94 | 248 | 53.5 | 6.25 | 6.22 | 0.98 |  Fe xiii | 204.942 | 0.96
209.92 | 271 | 144.5 | 6.25 | 6.22 | 0.94 |  Fe xiii | 209.916 | 0.96
202.04 | 9310 | 819.2 | 6.25 | 6.22 | 0.95 |  Fe xiii | 202.044 | 0.97
264.79 | 1300 | 181.7 | 6.29 | 6.23 | 0.97 |  Fe xiv | 264.789 | 0.81
|  |  |  |  |  |  Fe xi | 264.772 | 0.15
274.20 | 1890 | 223.8 | 6.29 | 6.24 | 0.98 |  Fe xiv | 274.204 | 0.96
252.20 | 81 | 31.6 | 6.29 | 6.24 | 1.16 |  Fe xiv | 252.200 | 0.95
289.15 | 26 | 19.9 | 6.29 | 6.24 | 0.92 |  Fe xiv | 289.151 | 0.96
270.52 | 814 | 96.7 | 6.29 | 6.24 | 1.00 |  Fe xiv | 270.521 | 0.96
257.40 | 221 | 45.3 | 6.29 | 6.24 | 1.53 |  Fe xiv | 257.394 | 0.96
211.32 | 632 | 392.7 | 6.29 | 6.24 | 1.00 |  Fe xiv | 211.317 | 0.96
284.16 | 1560 | 508.3 | 6.34 | 6.27 | 1.01 |  Fe xv | 284.163 | 0.96
Table 7: Same as Table 1, but for a QS off-limb observation on 7 Oct 2013 $\lambda_{\rm obs}$ | DN | $I_{\rm obs}$ |  log $T_{\rm max}$ |  log $T_{\rm eff}$ | $R$ | Ion | $\lambda_{\rm exp}$ | $r$
---|---|---|---|---|---|---|---|---
194.66 | 513 | 11.7 | 5.72 | 6.01 | 0.88 |  Fe viii | 194.661 | 0.94
186.60 | 514 | 38.9 | 5.73 | 6.04 | 1.00 |  Fe viii | 186.598 | 0.82
185.22 | 365 | 45.3 | 5.73 | 6.05 | 1.17 |  Fe viii | 185.213 | 0.86
189.94 | 566 | 26.7 | 5.94 | 6.10 | 1.12 |  Fe ix | 189.935 | 0.95
188.49 | 954 | 60.3 | 5.95 | 6.11 | 1.03 |  Fe ix | 188.493 | 0.83
197.85 | 981 | 28.0 | 5.96 | 6.11 | 1.10 |  Fe ix | 197.854 | 0.91
257.26 | 1130 | 268.7 | 6.04 | 6.15 | 0.90 |  Fe x | 257.259 | 0.24
|  |  |  |  |  |  Fe x | 257.263 | 0.74
177.24 | 354 | 824.7 | 6.05 | 6.15 | 0.97 |  Fe x | 177.240 | 0.97
174.53 | 188 | 1328.5 | 6.05 | 6.15 | 1.07 |  Fe x | 174.531 | 0.97
184.54 | 2230 | 330.4 | 6.05 | 6.16 | 0.93 |  Fe x | 184.537 | 0.94
190.04 | 3100 | 142.8 | 6.06 | 6.17 | 1.06 |  Fe xii | 190.040 | 0.23
|  |  |  |  |  |  Fe x | 190.037 | 0.63
184.79 | 207 | 28.8 | 6.12 | 6.18 | 1.05 |  Fe xi | 184.793 | 0.94
257.55 | 479 | 110.9 | 6.12 | 6.18 | 1.02 |  Fe xi | 257.554 | 0.68
|  |  |  |  |  |  Fe xi | 257.547 | 0.26
256.92 | 725 | 175.9 | 6.12 | 6.18 | 0.78 |  Fe xi | 256.919 | 0.89
182.17 | 954 | 345.8 | 6.13 | 6.18 | 0.81 |  Fe xi | 182.167 | 0.96
192.81 | 7840 | 220.4 | 5.42 | 6.18 | 0.90 |  Fe xi | 192.813 | 0.96
181.13 | 204 | 106.4 | 6.13 | 6.18 | 0.91 |  Fe xi | 181.130 | 0.97
188.30 | 8990 | 581.8 | 6.13 | 6.18 | 0.98 |  Fe xi | 188.299 | 0.97
188.22 | 15900 | 1030.8 | 6.13 | 6.18 | 0.91 |  Fe xi | 188.216 | 0.97
180.40 | 2880 | 1927.1 | 6.13 | 6.18 | 1.01 |  Fe xi | 180.401 | 0.97
202.71 | 852 | 75.9 | 6.13 | 6.19 | 1.09 |  Fe xi | 202.705 | 0.90
258.37 | 1990 | 435.5 | 6.15 | 6.19 | 0.88 |  Si x | 258.374 | 0.97
253.79 | 278 | 88.5 | 6.15 | 6.19 | 0.85 |  Si x | 253.790 | 0.97
271.99 | 1580 | 192.4 | 6.15 | 6.19 | 0.83 |  Si x | 271.992 | 0.97
261.06 | 1260 | 229.3 | 6.15 | 6.19 | 0.84 |  Si x | 261.056 | 0.98
277.27 | 836 | 133.8 | 6.15 | 6.19 | 0.91 |  Si x | 277.264 | 0.98
256.40 | 1550 | 393.3 | 6.16 | 6.20 | 1.04 |  Si x | 256.377 | 0.56
|  |  |  |  |  |  Fe xiii | 256.400 | 0.15
|  |  |  |  |  |  Fe xii | 256.410 | 0.20
249.39 | 184 | 91.0 | 6.19 | 6.20 | 1.00 |  Fe xii | 249.388 | 0.71
|  |  |  |  |  |  Fe xii | 249.384 | 0.23
196.64 | 4250 | 107.1 | 6.19 | 6.20 | 1.04 |  Fe xii | 196.640 | 0.94
186.88 | 5200 | 367.1 | 6.19 | 6.20 | 1.13 |  Fe xii | 186.854 | 0.17
|  |  |  |  |  |  Fe xii | 186.887 | 0.76
193.51 | 40100 | 885.9 | 6.19 | 6.20 | 1.40 |  Fe xii | 193.509 | 0.95
192.39 | 18200 | 550.9 | 6.19 | 6.20 | 1.05 |  Fe xii | 192.394 | 0.96
195.12 | 63200 | 1284.7 | 6.19 | 6.20 | 1.40 |  Fe xii | 195.119 | 0.97
196.52 | 1760 | 43.6 | 6.24 | 6.22 | 1.04 |  Fe xiii | 196.525 | 0.93
200.02 | 3390 | 140.2 | 6.25 | 6.22 | 0.85 |  Fe xiii | 200.021 | 0.95
261.73 | 241 | 42.2 | 6.25 | 6.22 | 1.02 |  Fe xiii | 261.743 | 0.96
203.83 | 3600 | 440.5 | 6.25 | 6.22 | 1.21 |  Fe xiii | 203.795 | 0.28
|  |  |  |  |  |  Fe xiii | 203.826 | 0.64
251.95 | 945 | 354.6 | 6.25 | 6.22 | 1.02 |  Fe xiii | 251.952 | 0.97
204.94 | 706 | 121.4 | 6.25 | 6.22 | 0.77 |  Fe xiii | 204.942 | 0.96
209.92 | 691 | 272.0 | 6.25 | 6.22 | 0.81 |  Fe xiii | 209.916 | 0.96
202.04 | 18000 | 1466.4 | 6.25 | 6.22 | 0.86 |  Fe xiii | 202.044 | 0.96
264.79 | 2210 | 353.0 | 6.29 | 6.23 | 0.92 |  Fe xiv | 264.789 | 0.85
|  |  |  |  |  |  Fe xi | 264.772 | 0.11
274.20 | 3270 | 427.2 | 6.29 | 6.24 | 0.95 |  Fe xiv | 274.204 | 0.96
252.20 | 186 | 68.2 | 6.29 | 6.24 | 1.03 |  Fe xiv | 252.200 | 0.95
270.52 | 1460 | 204.2 | 6.29 | 6.24 | 0.89 |  Fe xiv | 270.521 | 0.96
211.32 | 1670 | 986.8 | 6.29 | 6.24 | 0.74 |  Fe xiv | 211.317 | 0.96
284.16 | 3350 | 1200.6 | 6.34 | 6.27 | 0.80 |  Fe xv | 284.163 | 0.96
262.98 | 143 | 23.4 | 6.43 | 6.31 | 0.92 |  Fe xvi | 262.976 | 0.63
|  |  |  |  |  |  Fe xiii | 262.984 | 0.32
Table 8: Same as Table 1, but for a QS off-limb observation on 7 Aug 2014 $\lambda_{\rm obs}$ | DN | $I_{\rm obs}$ |  log $T_{\rm max}$ |  log $T_{\rm eff}$ | $R$ | Ion | $\lambda_{\rm exp}$ | $r$
---|---|---|---|---|---|---|---|---
194.66 | 272 | 13.1 | 5.72 | 6.05 | 1.09 |  Fe viii | 194.661 | 0.96
185.22 | 265 | 70.9 | 5.73 | 6.06 | 1.01 |  Fe viii | 185.213 | 0.93
186.60 | 315 | 60.7 | 5.73 | 6.06 | 0.91 |  Fe viii | 186.598 | 0.84
189.94 | 578 | 60.3 | 5.94 | 6.08 | 0.84 |  Fe ix | 189.935 | 0.96
188.49 | 678 | 91.4 | 5.95 | 6.08 | 1.11 |  Fe ix | 188.493 | 0.87
197.85 | 1060 | 64.9 | 5.96 | 6.08 | 0.78 |  Fe ix | 197.854 | 0.95
257.26 | 928 | 470.9 | 6.04 | 6.09 | 0.72 |  Fe x | 257.259 | 0.24
|  |  |  |  |  |  Fe x | 257.263 | 0.74
177.24 | 229 | 1152.0 | 6.05 | 6.10 | 0.92 |  Fe x | 177.240 | 0.98
174.53 | 117 | 1788.6 | 6.05 | 6.10 | 1.04 |  Fe x | 174.531 | 0.98
184.54 | 1470 | 498.8 | 6.05 | 6.10 | 0.79 |  Fe x | 184.537 | 0.97
190.04 | 1870 | 191.9 | 6.06 | 6.10 | 0.81 |  Fe x | 190.037 | 0.80
256.92 | 303 | 157.6 | 6.12 | 6.11 | 0.72 |  Fe xi | 256.919 | 0.93
181.13 | 69 | 77.8 | 6.13 | 6.11 | 0.99 |  Fe xi | 181.130 | 0.96
182.17 | 317 | 247.8 | 6.13 | 6.11 | 0.90 |  Fe xi | 182.167 | 0.97
192.81 | 2670 | 159.7 | 5.42 | 6.11 | 0.98 |  Fe xi | 192.813 | 0.96
188.22 | 5080 | 718.5 | 6.13 | 6.11 | 1.03 |  Fe xi | 188.216 | 0.98
188.30 | 3560 | 495.2 | 6.13 | 6.11 | 0.92 |  Fe xi | 188.299 | 0.98
180.40 | 1020 | 1484.1 | 6.13 | 6.11 | 1.04 |  Fe xi | 180.401 | 0.98
202.71 | 275 | 62.2 | 6.13 | 6.11 | 1.01 |  Fe xi | 202.705 | 0.95
258.37 | 596 | 279.7 | 6.15 | 6.12 | 0.91 |  Si x | 258.374 | 0.97
253.79 | 75 | 50.0 | 6.15 | 6.12 | 1.01 |  Si x | 253.790 | 0.97
256.40 | 511 | 275.1 | 6.16 | 6.12 | 0.89 |  Si x | 256.377 | 0.62
|  |  |  |  |  |  Fe xii | 256.410 | 0.15
|  |  |  |  |  |  Fe x | 256.398 | 0.14
271.99 | 451 | 117.8 | 6.15 | 6.12 | 0.90 |  Si x | 271.992 | 0.98
261.06 | 361 | 141.3 | 6.15 | 6.12 | 0.90 |  Si x | 261.056 | 0.98
277.27 | 240 | 82.2 | 6.15 | 6.12 | 0.99 |  Si x | 277.264 | 0.98
249.39 | 47 | 49.2 | 6.19 | 6.12 | 0.88 |  Fe xii | 249.388 | 0.68
|  |  |  |  |  |  Fe xii | 249.384 | 0.21
196.64 | 836 | 45.2 | 6.19 | 6.13 | 1.08 |  Fe xii | 196.640 | 0.93
186.88 | 872 | 158.9 | 6.19 | 6.13 | 1.12 |  Fe xii | 186.854 | 0.17
|  |  |  |  |  |  Fe xii | 186.887 | 0.78
193.51 | 7550 | 387.7 | 6.19 | 6.13 | 1.34 |  Fe xii | 193.509 | 0.94
192.39 | 3240 | 209.5 | 6.19 | 6.13 | 1.13 |  Fe xii | 192.394 | 0.96
195.12 | 12100 | 528.0 | 6.19 | 6.13 | 1.40 |  Fe xii | 195.119 | 0.97
264.79 | 187 | 63.9 | 6.29 | 6.14 | 0.90 |  Fe xiv | 264.789 | 0.44
|  |  |  |  |  |  Fe xi | 264.772 | 0.53
200.02 | 394 | 34.6 | 6.25 | 6.14 | 0.73 |  Fe xiii | 200.021 | 0.91
203.83 | 255 | 78.7 | 6.25 | 6.14 | 1.37 |  Fe xiii | 203.795 | 0.28
|  |  |  |  |  |  Fe xiii | 203.826 | 0.64
251.95 | 90 | 70.6 | 6.25 | 6.14 | 1.03 |  Fe xiii | 251.952 | 0.96
209.92 | 42 | 35.3 | 6.25 | 6.14 | 1.22 |  Fe xiii | 209.916 | 0.94
204.94 | 48 | 18.5 | 6.25 | 6.14 | 1.00 |  Fe xiii | 204.942 | 0.95
202.04 | 1620 | 286.4 | 6.25 | 6.15 | 0.85 |  Fe xiii | 202.044 | 0.96
274.20 | 135 | 42.3 | 6.29 | 6.15 | 0.96 |  Fe xiv | 274.204 | 0.87
211.32 | 60 | 77.2 | 6.29 | 6.16 | 0.86 |  Fe xiv | 211.317 | 0.94
270.52 | 65 | 19.6 | 6.29 | 6.16 | 0.84 |  Fe xiv | 270.521 | 0.96
284.16 | 45 | 34.9 | 6.34 | 6.19 | 1.14 |  Fe xv | 284.163 | 0.96
Table 9: Same as Table 1, but for a QS off-limb observation on 6 Aug 2016 $\lambda_{\rm obs}$ | DN | $I_{\rm obs}$ |  log $T_{\rm max}$ |  log $T_{\rm eff}$ | $R$ | Ion | $\lambda_{\rm exp}$ | $r$
---|---|---|---|---|---|---|---|---
194.66 | 116 | 6.4 | 5.72 | 6.04 | 0.90 |  Fe viii | 194.661 | 0.91
185.22 | 110 | 25.5 | 5.73 | 6.06 | 1.17 |  Fe viii | 185.213 | 0.83
186.60 | 147 | 24.4 | 5.73 | 6.07 | 0.91 |  Fe viii | 186.598 | 0.77
189.94 | 185 | 19.0 | 5.94 | 6.13 | 1.03 |  Fe ix | 189.935 | 0.94
188.49 | 401 | 47.3 | 5.95 | 6.14 | 0.88 |  Fe ix | 188.493 | 0.80
197.85 | 369 | 19.1 | 5.96 | 6.14 | 1.09 |  Fe ix | 197.854 | 0.89
257.26 | 510 | 224.5 | 6.04 | 6.17 | 0.82 |  Fe x | 257.259 | 0.23
|  |  |  |  |  |  Fe x | 257.263 | 0.74
174.53 | 92 | 1225.3 | 6.05 | 6.17 | 0.91 |  Fe x | 174.531 | 0.97
177.24 | 166 | 718.4 | 6.05 | 6.17 | 0.87 |  Fe x | 177.240 | 0.97
184.54 | 956 | 304.6 | 6.05 | 6.17 | 0.79 |  Fe x | 184.537 | 0.93
190.04 | 1240 | 125.0 | 6.06 | 6.18 | 0.99 |  Fe xii | 190.040 | 0.25
|  |  |  |  |  |  Fe x | 190.037 | 0.60
184.79 | 96 | 27.2 | 6.12 | 6.19 | 0.95 |  Fe xi | 184.793 | 0.95
257.55 | 228 | 98.7 | 6.12 | 6.19 | 0.98 |  Fe xi | 257.554 | 0.68
|  |  |  |  |  |  Fe xi | 257.547 | 0.26
189.02 | 199 | 22.3 | 6.13 | 6.19 | 0.94 |  Fe xi | 188.997 | 0.95
256.92 | 324 | 146.4 | 6.12 | 6.19 | 0.80 |  Fe xi | 256.919 | 0.89
182.17 | 383 | 258.9 | 6.13 | 6.19 | 0.93 |  Fe xi | 182.167 | 0.96
192.81 | 3000 | 185.7 | 5.42 | 6.19 | 0.93 |  Fe xi | 192.813 | 0.96
181.13 | 79 | 77.2 | 6.13 | 6.19 | 1.08 |  Fe xi | 181.130 | 0.97
188.30 | 4060 | 489.6 | 6.13 | 6.19 | 1.01 |  Fe xi | 188.299 | 0.97
188.22 | 6520 | 796.2 | 6.13 | 6.19 | 1.02 |  Fe xi | 188.216 | 0.97
180.40 | 1320 | 1650.5 | 6.13 | 6.19 | 1.03 |  Fe xi | 180.401 | 0.97
202.71 | 271 | 54.2 | 6.13 | 6.19 | 1.33 |  Fe xi | 202.705 | 0.90
258.37 | 906 | 370.1 | 6.15 | 6.20 | 0.91 |  Si x | 258.374 | 0.97
253.79 | 116 | 66.7 | 6.15 | 6.20 | 0.99 |  Si x | 253.790 | 0.97
271.99 | 646 | 158.1 | 6.15 | 6.20 | 0.89 |  Si x | 271.992 | 0.97
261.06 | 566 | 192.1 | 6.15 | 6.20 | 0.88 |  Si x | 261.056 | 0.98
277.27 | 292 | 109.8 | 6.15 | 6.20 | 0.98 |  Si x | 277.264 | 0.98
249.39 | 109 | 97.8 | 6.19 | 6.20 | 0.84 |  Fe xii | 249.388 | 0.72
|  |  |  |  |  |  Fe xii | 249.384 | 0.23
196.64 | 1680 | 87.3 | 6.19 | 6.21 | 1.15 |  Fe xii | 196.640 | 0.94
186.88 | 2280 | 360.3 | 6.19 | 6.21 | 1.05 |  Fe xii | 186.854 | 0.17
|  |  |  |  |  |  Fe xii | 186.887 | 0.76
193.51 | 17800 | 951.5 | 6.19 | 6.21 | 1.18 |  Fe xii | 193.509 | 0.95
195.12 | 27900 | 1319.5 | 6.19 | 6.21 | 1.24 |  Fe xii | 195.119 | 0.97
192.39 | 7770 | 486.5 | 6.19 | 6.21 | 1.08 |  Fe xii | 192.394 | 0.96
196.52 | 753 | 39.0 | 6.24 | 6.22 | 1.07 |  Fe xiii | 196.525 | 0.93
200.02 | 1440 | 110.2 | 6.25 | 6.22 | 0.99 |  Fe xiii | 200.021 | 0.95
261.73 | 108 | 35.1 | 6.25 | 6.22 | 1.12 |  Fe xiii | 261.743 | 0.97
203.83 | 1580 | 444.0 | 6.25 | 6.22 | 1.10 |  Fe xiii | 203.795 | 0.28
|  |  |  |  |  |  Fe xiii | 203.826 | 0.64
251.95 | 513 | 348.0 | 6.25 | 6.22 | 0.96 |  Fe xiii | 251.952 | 0.97
204.94 | 266 | 94.3 | 6.25 | 6.22 | 0.91 |  Fe xiii | 204.942 | 0.96
209.92 | 247 | 193.3 | 6.25 | 6.22 | 1.04 |  Fe xiii | 209.916 | 0.96
202.04 | 7390 | 1136.1 | 6.25 | 6.22 | 1.02 |  Fe xiii | 202.044 | 0.96
264.79 | 1070 | 318.3 | 6.29 | 6.23 | 0.91 |  Fe xiv | 264.789 | 0.85
|  |  |  |  |  |  Fe xi | 264.772 | 0.11
274.20 | 1370 | 373.0 | 6.29 | 6.23 | 0.98 |  Fe xiv | 274.204 | 0.96
252.20 | 97 | 64.5 | 6.29 | 6.23 | 0.98 |  Fe xiv | 252.200 | 0.95
270.52 | 680 | 180.7 | 6.29 | 6.24 | 0.91 |  Fe xiv | 270.521 | 0.96
211.32 | 659 | 654.5 | 6.29 | 6.24 | 1.00 |  Fe xiv | 211.317 | 0.96
284.16 | 1090 | 916.4 | 6.34 | 6.25 | 0.89 |  Fe xv | 284.163 | 0.96
Table 10: Same as Table 1, but for a QS off-limb observation on 28 July 2017 $\lambda_{\rm obs}$ | DN | $I_{\rm obs}$ |  log $T_{\rm max}$ |  log $T_{\rm eff}$ | $R$ | Ion | $\lambda_{\rm exp}$ | $r$
---|---|---|---|---|---|---|---|---
194.66 | 278 | 17.5 | 5.72 | 6.05 | 0.86 |  Fe viii | 194.661 | 0.95
185.22 | 233 | 59.9 | 5.73 | 6.05 | 1.21 |  Fe viii | 185.213 | 0.96
186.60 | 302 | 55.5 | 5.73 | 6.06 | 1.02 |  Fe viii | 186.598 | 0.86
189.94 | 571 | 62.8 | 5.94 | 6.09 | 0.84 |  Fe ix | 189.935 | 0.96
188.49 | 850 | 111.0 | 5.95 | 6.09 | 0.95 |  Fe ix | 188.493 | 0.89
197.85 | 933 | 56.6 | 5.96 | 6.09 | 0.95 |  Fe ix | 197.854 | 0.94
257.26 | 893 | 425.8 | 6.04 | 6.11 | 0.90 |  Fe x | 257.259 | 0.23
|  |  |  |  |  |  Fe x | 257.263 | 0.75
177.24 | 241 | 1246.1 | 6.05 | 6.11 | 0.96 |  Fe x | 177.240 | 0.98
174.53 | 128 | 2006.8 | 6.05 | 6.11 | 1.06 |  Fe x | 174.531 | 0.98
184.54 | 1570 | 550.6 | 6.05 | 6.11 | 0.81 |  Fe x | 184.537 | 0.97
190.04 | 2100 | 227.9 | 6.06 | 6.12 | 0.81 |  Fe xii | 190.040 | 0.12
|  |  |  |  |  |  Fe x | 190.037 | 0.77
192.02 | 518 | 41.4 | 5.74 | 6.12 | 0.91 |  Fe xi | 192.021 | 0.84
184.79 | 110 | 34.1 | 6.11 | 6.12 | 1.04 |  Fe xi | 184.793 | 0.80
|  |  |  |  |  |  Fe x | 184.828 | 0.14
257.55 | 254 | 118.4 | 6.12 | 6.13 | 1.02 |  Fe xi | 257.554 | 0.70
|  |  |  |  |  |  Fe xi | 257.547 | 0.26
256.92 | 379 | 185.2 | 6.12 | 6.13 | 0.79 |  Fe xi | 256.919 | 0.92
182.17 | 451 | 362.8 | 6.13 | 6.13 | 0.77 |  Fe xi | 182.167 | 0.97
181.13 | 93 | 107.3 | 6.13 | 6.13 | 0.89 |  Fe xi | 181.130 | 0.97
188.22 | 6750 | 917.3 | 6.13 | 6.13 | 1.04 |  Fe xi | 188.216 | 0.98
188.30 | 4190 | 563.3 | 6.13 | 6.13 | 1.04 |  Fe xi | 188.299 | 0.98
192.81 | 3440 | 244.1 | 5.42 | 6.13 | 0.83 |  Fe xi | 192.813 | 0.96
180.40 | 1310 | 1948.3 | 6.13 | 6.13 | 1.02 |  Fe xi | 180.401 | 0.98
202.71 | 340 | 76.6 | 6.13 | 6.13 | 1.06 |  Fe xi | 202.705 | 0.95
258.37 | 827 | 364.7 | 6.15 | 6.13 | 0.90 |  Si x | 258.374 | 0.97
253.79 | 118 | 73.1 | 6.15 | 6.13 | 0.89 |  Si x | 253.790 | 0.97
271.99 | 556 | 160.0 | 6.15 | 6.13 | 0.90 |  Si x | 271.992 | 0.97
261.06 | 530 | 194.3 | 6.15 | 6.13 | 0.89 |  Si x | 261.056 | 0.98
277.27 | 288 | 124.5 | 6.15 | 6.13 | 0.88 |  Si x | 277.264 | 0.98
256.40 | 697 | 353.8 | 6.16 | 6.13 | 0.94 |  Si x | 256.377 | 0.62
|  |  |  |  |  |  Fe xii | 256.410 | 0.16
|  |  |  |  |  |  Fe x | 256.398 | 0.11
249.39 | 47 | 46.2 | 6.19 | 6.14 | 1.34 |  Fe xii | 249.388 | 0.69
|  |  |  |  |  |  Fe xii | 249.384 | 0.22
196.64 | 1220 | 68.3 | 6.19 | 6.14 | 1.00 |  Fe xii | 196.640 | 0.93
186.88 | 1480 | 260.6 | 6.19 | 6.15 | 0.95 |  Fe xii | 186.854 | 0.17
|  |  |  |  |  |  Fe xii | 186.887 | 0.78
193.51 | 11600 | 707.2 | 6.19 | 6.15 | 1.12 |  Fe xii | 193.509 | 0.94
192.39 | 5210 | 393.8 | 6.19 | 6.15 | 0.92 |  Fe xii | 192.394 | 0.96
195.12 | 17700 | 899.4 | 6.19 | 6.15 | 1.26 |  Fe xii | 195.119 | 0.97
200.02 | 683 | 56.4 | 6.25 | 6.16 | 0.77 |  Fe xiii | 200.021 | 0.89
196.52 | 379 | 20.9 | 6.24 | 6.16 | 0.81 |  Fe xiii | 196.525 | 0.88
264.79 | 338 | 108.4 | 6.29 | 6.16 | 0.90 |  Fe xiv | 264.789 | 0.57
|  |  |  |  |  |  Fe xi | 264.772 | 0.40
203.83 | 527 | 168.7 | 6.25 | 6.16 | 1.07 |  Fe xiii | 203.795 | 0.28
|  |  |  |  |  |  Fe xiii | 203.826 | 0.64
251.95 | 192 | 140.7 | 6.25 | 6.16 | 0.94 |  Fe xiii | 251.952 | 0.97
209.92 | 92 | 78.2 | 6.25 | 6.16 | 1.07 |  Fe xiii | 209.916 | 0.95
204.94 | 101 | 44.0 | 6.25 | 6.16 | 0.78 |  Fe xiii | 204.942 | 0.95
202.04 | 3060 | 558.8 | 6.25 | 6.16 | 0.85 |  Fe xiii | 202.044 | 0.97
274.20 | 293 | 91.0 | 6.29 | 6.18 | 0.95 |  Fe xiv | 274.204 | 0.92
211.32 | 148 | 159.7 | 6.29 | 6.18 | 0.93 |  Fe xiv | 211.317 | 0.95
257.40 | 65 | 30.6 | 6.29 | 6.18 | 0.87 |  Fe xiv | 257.394 | 0.96
270.52 | 99 | 30.4 | 6.29 | 6.18 | 1.22 |  Fe xiv | 270.521 | 0.97
284.16 | 123 | 119.6 | 6.34 | 6.20 | 0.89 |  Fe xv | 284.163 | 0.96
Table 11: Same as Table 1, but for a QS off-limb observation on 28 June 2019 $\lambda_{\rm obs}$ | DN | $I_{\rm obs}$ |  log $T_{\rm max}$ |  log $T_{\rm eff}$ | $R$ | Ion | $\lambda_{\rm exp}$ | $r$
---|---|---|---|---|---|---|---|---
194.66 | 417 | 24.4 | 5.72 | 6.07 | 0.80 |  Fe viii | 194.661 | 0.95
185.22 | 412 | 99.3 | 5.73 | 6.07 | 0.94 |  Fe viii | 185.213 | 0.95
186.60 | 464 | 74.8 | 5.73 | 6.07 | 0.99 |  Fe viii | 186.598 | 0.83
189.94 | 785 | 67.3 | 5.94 | 6.09 | 1.11 |  Fe ix | 189.935 | 0.97
188.49 | 1290 | 170.0 | 5.95 | 6.09 | 0.86 |  Fe ix | 188.493 | 0.89
197.85 | 1320 | 78.0 | 5.96 | 6.09 | 0.96 |  Fe ix | 197.854 | 0.94
257.26 | 1510 | 587.6 | 6.04 | 6.11 | 0.90 |  Fe x | 257.259 | 0.25
|  |  |  |  |  |  Fe x | 257.263 | 0.73
177.24 | 346 | 1672.1 | 6.05 | 6.11 | 1.02 |  Fe x | 177.240 | 0.98
174.53 | 177 | 2598.2 | 6.05 | 6.11 | 1.16 |  Fe x | 174.531 | 0.98
184.54 | 2280 | 626.5 | 6.05 | 6.11 | 1.02 |  Fe x | 184.537 | 0.96
190.04 | 3050 | 256.1 | 6.06 | 6.12 | 1.05 |  Fe xii | 190.040 | 0.13
|  |  |  |  |  |  Fe x | 190.037 | 0.75
184.79 | 164 | 42.8 | 6.12 | 6.13 | 1.22 |  Fe xi | 184.793 | 0.94
257.55 | 441 | 169.8 | 6.12 | 6.14 | 1.07 |  Fe xi | 257.554 | 0.70
|  |  |  |  |  |  Fe xi | 257.547 | 0.26
256.92 | 608 | 241.2 | 6.12 | 6.14 | 0.87 |  Fe xi | 256.919 | 0.92
189.02 | 427 | 48.1 | 6.13 | 6.14 | 0.86 |  Fe xi | 188.997 | 0.96
182.17 | 710 | 534.9 | 6.13 | 6.14 | 0.81 |  Fe xi | 182.167 | 0.97
181.13 | 150 | 163.6 | 6.13 | 6.14 | 0.92 |  Fe xi | 181.130 | 0.97
188.22 | 9190 | 1271.2 | 6.13 | 6.14 | 1.11 |  Fe xi | 188.216 | 0.97
188.30 | 6090 | 834.3 | 6.13 | 6.14 | 1.03 |  Fe xi | 188.299 | 0.97
192.81 | 5040 | 329.8 | 5.42 | 6.14 | 0.91 |  Fe xi | 192.813 | 0.96
180.40 | 1820 | 2525.3 | 6.13 | 6.14 | 1.16 |  Fe xi | 180.401 | 0.97
202.71 | 424 | 87.9 | 6.13 | 6.14 | 1.38 |  Fe xi | 202.705 | 0.93
258.37 | 1460 | 545.1 | 6.15 | 6.15 | 0.98 |  Si x | 258.374 | 0.97
253.79 | 223 | 115.0 | 6.15 | 6.15 | 0.92 |  Si x | 253.790 | 0.97
271.99 | 852 | 226.4 | 6.15 | 6.15 | 0.95 |  Si x | 271.992 | 0.97
261.06 | 853 | 274.5 | 6.15 | 6.15 | 0.94 |  Si x | 261.056 | 0.98
277.27 | 452 | 181.3 | 6.15 | 6.15 | 0.91 |  Si x | 277.264 | 0.98
256.40 | 1050 | 430.4 | 6.16 | 6.15 | 1.20 |  Si x | 256.377 | 0.60
|  |  |  |  |  |  Fe xii | 256.410 | 0.17
|  |  |  |  |  |  Fe x | 256.398 | 0.11
249.39 | 107 | 92.1 | 6.19 | 6.16 | 1.12 |  Fe xii | 249.388 | 0.70
|  |  |  |  |  |  Fe xii | 249.384 | 0.22
196.64 | 2360 | 129.1 | 6.19 | 6.16 | 0.97 |  Fe xii | 196.640 | 0.94
186.88 | 3170 | 480.7 | 6.19 | 6.16 | 0.97 |  Fe xii | 186.854 | 0.17
|  |  |  |  |  |  Fe xii | 186.887 | 0.77
193.51 | 18200 | 1032.8 | 6.19 | 6.17 | 1.25 |  Fe xii | 193.509 | 0.94
192.39 | 8090 | 569.2 | 6.19 | 6.17 | 1.05 |  Fe xii | 192.394 | 0.96
195.12 | 27800 | 1411.7 | 6.19 | 6.17 | 1.31 |  Fe xii | 195.119 | 0.97
196.52 | 751 | 40.7 | 6.24 | 6.19 | 0.94 |  Fe xiii | 196.525 | 0.91
200.02 | 1510 | 109.3 | 6.25 | 6.19 | 0.90 |  Fe xiii | 200.021 | 0.94
261.73 | 92 | 28.4 | 6.25 | 6.19 | 1.13 |  Fe xiii | 261.743 | 0.97
203.83 | 1600 | 417.7 | 6.25 | 6.19 | 1.04 |  Fe xiii | 203.795 | 0.28
|  |  |  |  |  |  Fe xiii | 203.826 | 0.65
251.95 | 421 | 269.2 | 6.25 | 6.19 | 1.01 |  Fe xiii | 251.952 | 0.96
204.94 | 180 | 59.0 | 6.25 | 6.19 | 1.18 |  Fe xiii | 204.942 | 0.96
209.92 | 135 | 149.7 | 6.25 | 6.19 | 1.04 |  Fe xiii | 209.916 | 0.95
202.04 | 5070 | 909.0 | 6.25 | 6.19 | 0.98 |  Fe xiii | 202.044 | 0.96
264.79 | 858 | 239.6 | 6.29 | 6.19 | 0.92 |  Fe xiv | 264.789 | 0.71
|  |  |  |  |  |  Fe xi | 264.772 | 0.26
274.20 | 835 | 238.7 | 6.29 | 6.21 | 0.96 |  Fe xiv | 274.204 | 0.94
252.20 | 58 | 36.4 | 6.29 | 6.21 | 1.10 |  Fe xiv | 252.200 | 0.94
257.40 | 180 | 69.9 | 6.29 | 6.21 | 1.05 |  Fe xiv | 257.394 | 0.96
211.32 | 370 | 418.2 | 6.29 | 6.21 | 0.97 |  Fe xiv | 211.317 | 0.96
270.52 | 398 | 112.4 | 6.29 | 6.21 | 0.91 |  Fe xiv | 270.521 | 0.96
284.16 | 445 | 388.2 | 6.34 | 6.23 | 1.02 |  Fe xv | 284.163 | 0.96
Table 12: Same as Table 1, but for an off-limb observation on 5 April 2020 (active Sun) $\lambda_{\rm obs}$ | DN | $I_{\rm obs}$ |  log $T_{\rm max}$ |  log $T_{\rm eff}$ | $R$ | Ion | $\lambda_{\rm exp}$ | $r$
---|---|---|---|---|---|---|---|---
194.66 | 1220 | 71.4 | 5.72 | 5.91 | 0.96 |  Fe viii | 194.661 | 0.97
189.94 | 1140 | 97.4 | 5.94 | 6.06 | 1.14 |  Fe ix | 189.935 | 0.97
188.49 | 1560 | 205.9 | 5.95 | 6.06 | 1.02 |  Fe ix | 188.493 | 0.90
197.85 | 1540 | 91.2 | 5.96 | 6.08 | 1.05 |  Fe ix | 197.854 | 0.91
257.26 | 1400 | 546.5 | 6.04 | 6.12 | 0.88 |  Fe x | 257.259 | 0.38
|  |  |  |  |  |  Fe x | 257.263 | 0.60
186.60 | 1560 | 252.8 | 5.73 | 6.13 | 1.11 |  Ca xiv | 186.610 | 0.17
|  |  |  |  |  |  Fe viii | 186.598 | 0.74
174.53 | 217 | 3193.6 | 6.05 | 6.13 | 1.08 |  Fe x | 174.531 | 0.98
177.24 | 418 | 2020.2 | 6.05 | 6.13 | 0.97 |  Fe x | 177.240 | 0.97
185.22 | 2190 | 528.3 | 5.73 | 6.14 | 0.80 |  Ni xvi | 185.230 | 0.26
|  |  |  |  |  |  Fe viii | 185.213 | 0.71
184.54 | 2840 | 781.1 | 6.05 | 6.14 | 1.02 |  Fe x | 184.537 | 0.92
190.04 | 3690 | 310.4 | 6.05 | 6.15 | 1.22 |  Fe xii | 190.040 | 0.19
|  |  |  |  |  |  Fe x | 190.037 | 0.64
184.79 | 498 | 129.9 | 6.12 | 6.17 | 1.30 |  Fe xi | 184.793 | 0.95
257.55 | 669 | 257.5 | 6.12 | 6.17 | 1.09 |  Fe xi | 257.554 | 0.68
|  |  |  |  |  |  Fe xi | 257.547 | 0.25
192.81 | 6680 | 437.5 | 5.42 | 6.17 | 0.95 |  Fe xi | 192.813 | 0.94
189.02 | 1250 | 141.4 | 6.13 | 6.18 | 0.97 |  Fe xi | 188.997 | 0.96
180.60 | 202 | 262.5 | 6.13 | 6.18 | 0.79 |  Fe xi | 180.594 | 0.96
181.13 | 263 | 287.3 | 6.13 | 6.18 | 1.01 |  Fe xi | 181.130 | 0.96
256.92 | 613 | 242.9 | 6.13 | 6.18 | 0.90 |  Fe xii | 256.946 | 0.11
|  |  |  |  |  |  Fe xi | 256.919 | 0.86
182.17 | 1280 | 964.9 | 6.13 | 6.18 | 0.83 |  Fe xi | 182.167 | 0.96
188.22 | 13600 | 1881.0 | 6.13 | 6.18 | 1.02 |  Fe xi | 188.216 | 0.97
188.30 | 8400 | 1150.7 | 6.13 | 6.18 | 0.99 |  Fe xi | 188.299 | 0.97
180.40 | 2720 | 3787.9 | 6.13 | 6.18 | 1.02 |  Fe xi | 180.401 | 0.97
271.99 | 1250 | 330.8 | 6.15 | 6.20 | 1.00 |  Si x | 271.992 | 0.97
258.37 | 2900 | 1088.4 | 6.15 | 6.20 | 1.03 |  Si x | 258.374 | 0.97
261.06 | 1170 | 374.8 | 6.15 | 6.20 | 1.03 |  Si x | 261.056 | 0.98
253.79 | 381 | 195.6 | 6.15 | 6.20 | 1.14 |  Si x | 253.790 | 0.97
277.27 | 573 | 230.0 | 6.15 | 6.20 | 1.10 |  Si x | 277.264 | 0.98
249.39 | 246 | 211.0 | 6.19 | 6.21 | 1.08 |  Fe xii | 249.388 | 0.72
|  |  |  |  |  |  Fe xii | 249.384 | 0.20
256.40 | 2490 | 1017.8 | 6.17 | 6.22 | 0.95 |  Si x | 256.377 | 0.48
|  |  |  |  |  |  Fe xiii | 256.400 | 0.22
|  |  |  |  |  |  Fe xii | 256.410 | 0.19
196.64 | 7500 | 411.2 | 6.19 | 6.22 | 0.92 |  Fe xii | 196.640 | 0.94
193.51 | 36700 | 2073.0 | 6.19 | 6.23 | 1.19 |  Fe xii | 193.509 | 0.95
192.39 | 15800 | 1110.8 | 6.20 | 6.23 | 1.04 |  Fe xii | 192.394 | 0.96
195.12 | 57900 | 2941.0 | 6.20 | 6.23 | 1.22 |  Fe xii | 195.119 | 0.97
186.88 | 11000 | 1664.6 | 6.19 | 6.23 | 0.93 |  Fe xii | 186.854 | 0.23
|  |  |  |  |  |  Fe xii | 186.887 | 0.69
196.52 | 6670 | 360.9 | 6.24 | 6.27 | 0.80 |  Fe xiii | 196.525 | 0.95
261.73 | 327 | 100.6 | 6.24 | 6.27 | 1.08 |  Fe xiii | 261.743 | 0.97
246.21 | 632 | 692.5 | 6.25 | 6.27 | 0.84 |  Fe xiii | 246.209 | 0.94
200.02 | 7700 | 555.3 | 6.25 | 6.27 | 1.08 |  Fe xiii | 200.021 | 0.96
251.95 | 1780 | 1131.8 | 6.25 | 6.27 | 0.95 |  Fe xiii | 251.952 | 0.97
203.83 | 9910 | 2591.9 | 6.25 | 6.27 | 1.09 |  Fe xiii | 203.795 | 0.27
|  |  |  |  |  |  Fe xiii | 203.826 | 0.69
204.94 | 684 | 224.1 | 6.25 | 6.27 | 1.11 |  Fe xiii | 204.942 | 0.96
209.92 | 270 | 300.5 | 6.25 | 6.27 | 1.11 |  Fe xiii | 209.916 | 0.95
202.04 | 11600 | 2080.3 | 6.25 | 6.27 | 0.91 |  Fe xiii | 202.044 | 0.96
264.79 | 7330 | 2033.9 | 6.29 | 6.31 | 0.89 |  Fe xiv | 264.789 | 0.92
274.20 | 6900 | 1978.6 | 6.29 | 6.31 | 0.93 |  Fe xiv | 274.204 | 0.96
252.20 | 771 | 476.8 | 6.29 | 6.32 | 0.88 |  Fe xiv | 252.200 | 0.96
270.52 | 3910 | 1102.0 | 6.29 | 6.32 | 0.83 |  Fe xiv | 270.521 | 0.97
211.32 | 3020 | 3410.9 | 6.30 | 6.32 | 0.99 |  Fe xiv | 211.317 | 0.97
257.40 | 1540 | 595.2 | 6.29 | 6.32 | 1.12 |  Fe xiv | 257.394 | 0.96
284.16 | 12800 | 11211.0 | 6.34 | 6.39 | 1.00 |  Fe xv | 284.163 | 0.98