Comparison Betweeen Measured and Modeled Relative Quantum Efficiency at Energies 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 used to verify the results of the QE 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 4.7.5 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.

 

$$\mu m$$ Device Loc. 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 1.211 -0.004 0.066 w103c4

$$\sigma$$ -0.0013
0.0066 0.013
0.023