UNIVERSIT . . AT BONN Physikalisches Institut - Prof. Dr. Norbert ...

4.3. Dynamic range 53
M a x im u m c o u n t r a te [M H z ]
1 4
1 3
1 2
1 1
1 0
9
8
7
6
V C o u n t = 2 4 k e V
5
V C o u n t = 1 0 k e V
3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0
P u ls e s iz e [k e V ]
Fig. 4.8: Average maximum count rate as a function of the current chopper pulse size in
keV in a 3 mm CdZnTe sensor at two different VCountTh threshold settings. The error
bars represent the module-wide standard deviation of the maximum rates. Both curves
show the expected linear dependence of the maximum rate on the pulse size.
M a x im u m c o u n t r a te [M H z ]
1 4
1 3
1 2
1 1
1 0
9
8
7
6
IC u rrIn j 6 (5 8 k e V )
IC u rrIn j 3 (4 3 k e V )
0 1 0 2 0 3 0 4 0 5 0 6 0
T h r e s h o ld [k e V ]
Fig. 4.9: Average maximum count rate as a function of the applied discriminator threshold
in keV in a 3 mm CdZnTe sensor at two different current chopper pulse sizes. The error
bars represent the module-wide standard deviation of the maximum rates.
43 keV pulse size :
NMax = (7.09 ± 0.09)MHz − (0.129 ± 0.005) MHz
58 keV pulse size :
keV · VCountT h
NMax = (6.66 ± 0.03)MHz + (0.111 ± 0.001) MHz
keV · VCountT h
(4.7)
(4.8)
These findings infer that the pulse shape of the CIX 0.2 preamplifier output closely follows
the theoretical prediction of the triangular shaped signals presented in Fig. 3.5.