from 2020/04 activity report. + TAKEDA resumed the research of solar soft X-ray irradiance using XRT data, after suspension for almost a year (to complete her similar study with Yohkoh/SXT data). At present, Takeda studies about the minimum condition of the corona in 2008-2010 and 2019-2020. In the course of this study, Takeda noticed that the co-alignment DB includes the periods with large errors in Sun center coordinates occasionally since May-2019. It was notified to K. Yoshimura on 11-March. from 2020/05 activity report. + TAKEDA continued to work on solar soft X-ray irradiance using XRT data, after suspension for almost a year (to complete her similar study with Yohkoh/SXT data). At present, Takeda studies about the minimum condition of the corona in 2008-2010 and 2019-2020. In the course of the irradiance study in the above, Takeda noticed that a CHIANTI software, isothermal.pro used in the analysis was not the latest version. However, the latest version of the isothermal.pro had an inconvenient feature (that pops up wedget window to select elemental abundances) and was unable to use in a background process. Therefore, Takeda wrote the author of the program (P. Young at GSFC) to modify the code on 1-Apr. P. Young quickly updated the software and the latest version became usable to us. from 2020/06 activity report. TAKEDA continued to work on solar soft X-ray irradiance using XRT data. These months Takeda investigates the factors that may effect the irradiance derived from XRT: (1) cosmetic correction of contamination and dust spots, (2) growth of the contamination layer controled by CCD bakeouts. (3) stray light subtracted from each full-disk images. (4) modification of XRT effective area functions by a series of stray light contaminations. The the investigation of the factor (1)-(3) is done and a html page is being prepared to share the results, while the factor (4) is still on going.