XRT Response Functions: effect of new atomic data (Chianti DB ver. 11.0.2, released Aug-2025).

(30-Dec-2025, by Aki Takeda)

The XRT temperature response functions were recalculated, in response to the release of new Chianti atomic database version 11.0.2 in August 2025. The new atomic database (Chianti 11.0.2) introduces a new ionization-equilbrium file, which is created 'on-the-fly' when required. In the previous versions, 'chianti.ioneq' was assumed.

quick review on the XRT temperature response basics.

1. The Response functions.

The solar spectra were calculated with the latest Chianti version 11.0.2. From the previous version (10.1), the 'coronal' and 'photospheric' abundance were updated to 'sun_coronal_2021_chianti.abund' and 'sun_photospheric_2021_asplund.abund', respectively. For comparison, the spectral files using the traditional coronal abundance files (sun_coronal_1992_feldman_ext.abund, and sun_coronal_2012_schmelz_ext.abund) were also calculated.
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_flux1102(logte, f1,f2, tim, /corona)
IDL> flux_c1992 = xrt_flux1102(logte, f1,f2, tim, /cr1992)
IDL> flux_h2012 = xrt_flux1102(logte, f1,f2, tim, /hybrid)
IDL> flux_p = xrt_flux1102(logte, f1,f2, tim, /photos)
IDL> flux10_c = xrt_flux1010(logte, f1,f2, tim, /corona)
IDL> flux10_c1992 = xrt_flux1010(logte, f1,f2, tim, /cr1992)
IDL> flux10_h2012 = xrt_flux1010(logte, f1,f2, tim, /hybrid)
IDL> flux10_p = xrt_flux1010(logte, f1,f2, tim, /photos)

[NOTE] The more generalized function, XRT_FLUX_CH.PRO was developed to calculate the flux with the most recent solar spectral data. This function uses the most recent solar spectrum by default, and can also use the older versions by specifying in the keyword. See the program header about how to use (e.g., $SSW/hinode/xrt/idl/response/xrt_flux_ch.pro).

[ Example of calculating XRT response functions ]
For details, see the description of http://solar.physics.montana.edu/HINODE/XRT/xrt_ssw/xrt_flux1010.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_flux1102(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-polyOpen/C-poly

2. The Filter Ratios.

These plots shows that the CHIANTI ver 10.1 database makes no significant difference in most filter ratio curves relative to those with version 10.0, except some thin filter pairs like Al_mesh/Ti_poly.

(click each plot to show detailed info)

Al-poly/Al-mesh Ti-poly/Al-mesh thin-Be/Al-meshthin-Be/Al-poly
med-Be/Al-polymed-Be/thin-Be med-Al/Al-polymed-Al/thin-Be (NG?)
thick-Al/med-Althick-Be/med-Bethick-Be/med-Al thick-Be/thick-Al
Ti-poly/Al-poly (NG pair)med-Al/med-Be (NG pair)

3. XRT_TEEM modification.

XRT_TEEM_CH1102.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 http://solar.physics.montana.edu/HINODE/XRT/xrt_ssw (or Ylstone:/disk/yla/software/xrt_ssw).
IDL> XRT_TEEM_CH1102, index1,data1,index2,data2,te,em, /corona       ; reads solspec_ch1102_cr2021chianti_chianti.genx
IDL> XRT_TEEM_CH1102, index1,data1,index2,data2,te,em, /photospheric ; reads solspec_ch1102_ph2021asplund_chianti.genx
IDL> XRT_TEEM_CH1102, index1,data1,index2,data2,te,em, /hybrid       ; reads solspec_ch1102_cr2012schmelz_chianti.genx
IDL> XRT_TEEM_CH1102, index1,data1,index2,data2,te,em, /cr1992       ; reads solspec_ch1102_cr1992feldman_chianti.genx
IDL> XRT_TEEM_CH1102, index1,data1,index2,data2,te,em, solar_spectrum='./solar_spectrum/solspec_ch1102_ph2015scott_chianti.genx'

[NOTE] The more generalized function, XRT_TEEM_CH.PRO was developed to calculate the flux with the most recent solar spectral data. This function uses the most recent solar spectrum by default, and can also use the older versions by specifying in the keyword. See the program header for how to use (e.g., $SSW/hinode/xrt/idl/response/xrt_teem_ch.pro).