Match-up between sim-SwiMM simulation and measured data, arr_x_co57_200_20_030619_2_c.

(1) Estimation of scattering components from BAT structure (summed Co57 spectrum of 32k detectors)

using data: arr_x_co57_200_20_030619_2_sim_A.fits


This figure shows the difference between a directly incoming radiation spectrum (Red line) and a incoming radiation spectrum after several scatterings (Black line) in a ideal detector which has an infinitely large energy resolution without the charge trapping and electric noise. Thus, an discrepancy from the red line is Compton scattring component from the BAT structure. To take out the scatter component, we put the flag up for an indirect incident photon in the detector, so that we make a histogram apart from the on-flag photons. Following this algorithm, we should clear away the scattring component between 40 keV and 80 keV, however, there are some component left ~50 photons. For this reason, we need to take care the algorithm less than perfect yet.

(2) Compare a suspectrum collected by Hecht relation (Cyan) with a maskweighting spectrum (Red)

using data: arr_x_co57_200_20_030619_2_sim_B.fits.gz (Cyan line)

using data: arr_x_co57_200_20_030619_2_G.fits (Red line)


This figure compares a summed spectrum collected by Hecht relation (Cyan line) with a spectrum applied the maskweighting method. The cyan spectrum is only directly incoming radiation one using the above same algorithm. Also, this maskweighting method is simple one, hence we don't consider about a cosine effect of a radiation source and any other effects in detail. Although you can see that the scattring components is removed very well in both spectra, the energy tail following 100 keV of the maskweighting spectrum (red line) is slightly less than the cyan spectrum. This is because we use the "easy" maskweighting method, so that we need to re-estimate the any detail effects with the use of more accurate maskweighting method by the help of Derek.

Co57 spectrum including the Compton scattering components (Liner display)

using data: arr_x_co57_200_20_030619_2_sim_B.fits.gz


(3) The maskweighting spectrum and a calibration data one

using data: arr_x_co57_200_20_030619_2_c.pha.root (Measured data:Red line)


We have evaluated a photon numbers using a Co57 absolute activity from Nadine's report and an irradiation exposure time (= 1073 sec), we simulated to generate the same photon numbers on sim-SwiMM, and processed using the same tools as used for the actual ground calibration data. This shows a calibration data spectrum (Red) and the SwiMM spectrum applied the maskweighting method (Blue). The calibration 122 keV peak is about 1.5 times larger than the simulation one. But there is not 3 times difference as Derek said.

using data: arr_x_co57_200_20_030619_2_G.fits (Simulation data: Blue line)


These spectra agree with the 122 keV peak each other.