XRT Response Functions: effect of new atomic data (Chianti ver. 9.0, released Mar-2019).

(1-Nov-2019, by Aki Takeda)
(15-Dec-2019, by AkT, added plots)
(6-Apr-2020, AkT, recalculated using the most recent isothermal.pro, ver.15, 1-Apr-2020)
(30-Oct-2020, AkT, added tck-Be/med-Be ratio plots.

The XRT temperature response functions were recalculated, in response to the release of new Chianti atomic database version 9.0.1 in March-2019. The new atomic database (Chianti 9.0.1) turned out to make only negligible change on the XRT response functions calclated with the previous versions of Chianti(ver. 8.0.0). However, the filter ratio curves with the thick_Be filter (tck_Be/tck_Al, tck_Be/med_Al, etc.) yeild 20-50% higher temperatures than the results with Chianti ver. 8.0.0 at the temperature range around logT=7.0.

quick review on the XRT temperature response basics.

1. The Response functions.

The solar spectra were calculated with the latest Chianti version 9.0, for 'coronal' (sun_coronal_1992_feldman_ext.abund), 'hybrid' (sun_coronal_2012_schmelz_ext.abund), and 'photospheric' (sun_photospheric_2015_scott.abund) abundances. Below are the previous versions for comparison. Then I modified XRT_FLUX.PRO so that it can access the above spectrum files by setting the corresponding keyword. Examples of usage are as follows (including older versions).

IDL> flux_c = xrt_flux0901(logte, f1,f2, tim, /corona)
IDL> flux_h = xrt_flux0901(logte, f1,f2, tim, /hybrid)
IDL> flux_p = xrt_flux0901(logte, f1,f2, tim, /photos)
IDL> flux_c8 = xrt_flux800(logte, f1,f2, tim, /corona)
IDL> flux_h8 = xrt_flux800(logte, f1,f2, tim, /hybrid)
IDL> flux_p8 = xrt_flux800(logte, f1,f2, tim, /photos)

[ Example of calculating XRT response functions ]
For details, see the description of Mithra:/www/HINODE/XRT/xrt_ssw/xrt_flux901.pro.

IDL> tim='1-may-2017 00:00'                ; change as needed.
IDL> f1=0 & f2=2                            ; for Open/Ti-poly 
IDL> logte = 5.+findgen(61)*0.05            ; prepare a temperature array
IDL> flux = xrt_flux901(logte, f1,f2,  tim, /corona)

Below are the response functions of all the X-ray analysis filters available at XRT. It is known that the contamination accumulated on the CCD modifies the XRT response functions. As the amount of contamination varies with time, response functions are time-dependant. For the later convenience of analysis, the following response functions were calculated for the contamination level as of 12-Nov-2006.

(Click each plot to show details)

Al-poly/Openthin-Be/Open med-Be/Openmed-Al/Open
Open/Al-meshOpen/thick-Al Open/thick-BeAl-poly/Ti-poly
Open/Ti-poly C-poly/Open

2. The Filter Ratios.

These plots shows that the CHIANTI ver 9.0.1 database makes no significant difference in most filter ratio curves relative to those with version 8.0.0, except the ratios with thick_Be filters (e.g., thick-Be/med-Al, thick-Be/thick-Al), for which, derived temperatures are 20-50% higher than the previous version at the temperature range logT is ~7.0.

(click each plot to show detailed info)

Al-poly/Al-meshthin-Be/Al-mesh thin-Be/Al-polymed-Be/Al-poly
med-Al/Al-polymed-Be/thin-Be med-Al/thin-Bemed-Al/med-Be
thick-Be/med-Althick-Be/thick-Al Ti-poly/Al-mesh thick-Be/med-Be

3. XRT_TEEM modification.

XRT_TEEM_CH901.PRO was prepared.

Instead of directly modifying XRT_TEEM, I made a wrapper procedure that sets up the arrays of specified solar spectrum, and passes them to XRT_TEEM. You can get it from Mithra:/www/HINODE/XRT/xrt_ssw (or Ylstone:/disk/yla/software/xrt_ssw).
IDL> XRT_TEEM_CH901, index1,data1,index2,data2,te,em, /corona
IDL> XRT_TEEM_CH901, index1,data1,index2,data2,te,em, /hybrid
IDL> XRT_TEEM_CH901, index1,data1,index2,data2,te,em, /photospheric
IDL> XRT_TEEM_CH901, index1,data1,index2,data2,te,em, solar_spectrum='./solar_spectrum/solspec_ch901_ph2015scott_chianti.genx'

4. Newly introduced abundances.

A new photosperic abundance set is introduced since the recent version. For comparison, I calculated the following two sets. The comparison plots of the response functions with new and old hybrid abundances for the 5 filters as samples.