Comparison Between Measured & Modeled Relative Quantum Efficiency above 5 keV

At energies above 4-5 keV quantum efficiency of the device depends entirely on the depletion depth. Consequently, the results of the depletion depth measurements described in Section 4.6.2 can be checked against the results of the quantum efficiency measurements of the flight devices relative to the reference chips. Since depletion depths were extracted from the data taken in the HIREFS chamber, the results of the two measurements are completely independent. Absolute QE numbers at two energies - 5.898 KeV (Manganese $K_{\alpha}$ line) and 8.047 keV (Copper $K_{\alpha}$ line) were calculated for both flight and reference devices based on the assumption that any photon interacting within the depleted layer will be detected. Table 4.31 shows the results of these calculations along with the results of the relative QE measurements in the big chambers. Both results are in good agreement.
 

Table 4.31: Comparison of relative QE measured directly and calculated from the results of depletion depth measurement

Device	Loc.	Deplet. depth, $\mu m$	Absolute QE (calculated)		Relative QE (calculated)		Relative QE (measured)		Rel. QE difference (meas.-calc.)		Reference device
			5.9 keV	8.05 keV	5.9 keV	8.05 keV	5.9 keV	8.05 keV	5.9 keV	8.05 keV
w203c4r	I0	64-65	0.875	0.594	1.039	1.086	1.031	1.106	-0.008	0.02	w103c4
w193c2	I1	64-65	0.875	0.594	1.039	1.086	1.033	1.087	-0.006	0.001	w103c4
w158c4r	I2	64-65	0.875	0.594	1.039	1.086	1.030	1.096	-0.009	0.01	w103c4
w215c2r	I3	64-65	0.871	0.588	0.974	0.94	0.986	0.932	0.012	-0.008	w190c3
w168c4r	S0	63-64	0.867	0.583	0.970	0.93	0.974	0.919	0.004	-0.011	w190c3
w182c4r	S2	75-76	0.905	0.646	1.07	1.18	1.068	1.211	-0.002	0.031	w103c4
w457c4	S4	70-72	0.894	0.626	1.00	1.00	1.000	1.003	0.000	0.003	w190c3
w201c3r	S5	71-72	0.894	0.626	1.00	1.00	1.001	1.008	0.001	0.008	w190c3
w103c4	ref	57	0.842	0.547
w190c3	ref	71	0.894	0.626	1.062	1.145	1.058	1.164	-0.004	0.019	w103c4
mean									-0.0013	0.008
$\sigma$									0.0066	0.014