Effective Area and Energy Resolution vs. Split Event Threshold

The HRMA/ACIS effective area and energy resolution were also evaluated for split event thresholds of 5 to 15 adu in steps of 2 adu.

Figure 6.5 and figure 6.6 show the dependence of effective area with split event threshold for ACIS CCD's I1 and S3. Tabular versions of the data are listed in Tables 6.13 and 6.14. Figures 6.7 and 6.8 show the dependence of energy resolution with split event threshold for ACIS CCD's I1 and S3. Tabular versions of the data are listed in Tables 6.15 and 6.16.

These results indicate that the HRMA/ACIS effective area and energy resolution do not vary considerably with split event threshold for FI CCD's, whereas the BI chip performance is significantly different, showing a significant dependence on split event threshold.
   

Figure 6.5: Effective Area vs. Energy for ACIS CCD I1 calculated for split event thresholds of 5, 7, 9, 11, 13 and 15 ADU

 

Energy keV	Effective Area
	5adu	7adu	9adu	11adu	13adu	15adu
	cm2	cm2	cm2	cm2	cm2	cm2
0.277	2.37	2.38	2.38	2.38	2.38	2.38
0.525	118.42	118.84	118.92	118.90	118.87	118.88
0.93	334.65	334.73	334.84	334.80	334.75	334.78
1.4867	569.80	570.06	570.10	570.06	570.06	570.03
3	284.07	286.06	286.15	286.31	286.28	286.3
4	339.75	344.87	345.65	345.87	345.91	346.14
5	305.37	315.73	318.24	319.62	320.80	321.60
6	137.45	153.44	161.07	165.56	168.88	171.71
7	52.08	63.97	71.07	75.96	79.82	82.86
8	19.66	25.06	28.67	31.63	34.23	36.31
9	8.12	10.19	11.75	13.13	14.44	15.63

The effective area values listed in this table apply for CCD ID = 1, a HRMA Pitch angle of 5 arcmin, a HRMA Yaw angle of -3.7 arcmin, and grade selection of g02346. Events within the entire CCD were considered.

 

Figure 6.6: Effective Area vs. Energy for ACIS CCD S3 calculated for split event thresholds of 5, 7, 9, 11, 13 and 15 ADU

 

Energy keV	Effective Area
	5adu	7adu	9adu	11adu	13adu	15adu
	cm2	cm2	cm2	cm2	cm2	cm2
0.277	137.02	159.79	165.75	167.60	168.43	169.10
0.525	295.19	360.90	384.35	391.97	394.43	395.79
0.93	439.99	535.67	572.61	586.07	591.09	592.62
3	167.70	245.80	299.84	332.17	348.93	355.37
4	124.12	189.12	241.82	282.05	307.53	321.12
5	76.47	124.05	165.86	199.18	224.27	240.84
6	45.15	69.54	92.15	112.64	129.18	140.04
7	35.28	50.68	63.98	76.14	87.31	94.09
8	16.70	22.91	28.42	33.20	37.13	39.94
9	10.29	14.86	18.51	21.87	24.54	26.58

The effective area values listed in this table apply for CCD ID = 7, a HRMA Pitch angle of 0 arcmin, a HRMA Yaw angle of 0 arcmin, and grade selection of g02346. Events within the entire CCD were considered.

  

Figure 6.7: Energy Resolution (FWHM) vs. Energy for ACIS CCD I1 calculated for split event thresholds of 5, 7, 9, 11, 13 and 15 ADU

Energy keV	Energy Resolution
	5adu	7adu	9adu	11adu	13adu	15adu
	eV	eV	eV	eV	eV	eV
0.277	45.97	46.30	44.86	45.33	45.68	44.85
0.525	55.59	55.42	54.64	54.64	54.73	55.19
0.93	60.38	60.25	60.83	60.58	60.98	61.22
1.4867	77.29	77.43	77.61	77.57	77.79	77.92
3	91.21	90.05	90.60	90.25	91.82	91.00
4	103.57	103.24	102.99	103.16	103.27	103.87
5	116.07	115.49	115.20	116.24	116.43	117.01
6	129.83	131.17	131.70	132.58	134.95	135.17
7	147.54	151.02	151.19	152.15	151.91	153.10
8	150.85	155.08	159.14	158.46	164.41	169.73
9	178.35	186.48	183.48	184.22	189.48	193.95

The energy resolution values listed in this table apply for CCD ID = 1, a HRMA Pitch angle of 5 arcmin, a HRMA Yaw angle of -3.7 arcmin, and grade selection of g02346. Events within the entire CCD were considered.
 

Figure 6.8: Energy Resolution (FWHM) vs. Energy for ACIS CCD S3 calculated for split event thresholds of 5, 7, 9, 11, 13 and 15 ADU

 

Energy keV	Energy Resolution
	5adu	7adu	9adu	11adu	13adu	15adu
	eV	eV	eV	eV	eV	eV
0.277	43.35	62.63	62.57	66.68	70.07	76.64
0.525	83.09	80.60	82.10	86.62	92.34	98.31
0.93	99.03	96.89	95.71	98.30	102.10	108.68
3	130.55	135.66	139.76	139.35	137.55	138.21
4	146.38	150.33	152.01	150.78	149.48	150.50
5	162.78	171.01	175.40	176.75	173.58	171.24
6	167.08	177.24	182.56	186.36	184.27	182.22
7	178.56	191.37	195.14	195.39	193.79	186.53
8	192.94	195.28	202.41	206.32	205.97	199.89
9	172.92	187.21	195.52	204.09	207.44	207.28

The energy resolution values listed in this table apply for CCD ID = 7, a HRMA Pitch angle of 0 arcmin, a HRMA Yaw angle of 0 arcmin, and grade selection of g02346. Events within the entire CCD were considered.