Amptek CoolFET A250CF Podręcznik - Strona 4

Przeglądaj online lub pobierz pdf Podręcznik dla Wzmacniacz Amptek CoolFET A250CF. Amptek CoolFET A250CF 7 stron. Charge sensitive preamplifier

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1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
-50
0
50
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
0
100
Figure 3. Timing and energy outputs from a typical test
pulser.
3.4
Connections
Input, Test, Energy, Timing: BNC
Bias: SHV
3.5
Power
3.3 V DC at 1.6 A (AC power adapter included)
3.6
Mechanical
Size: 3.5" x 2.5 "
Weight: 28 g
4 Preamplifier Configuration,
Adjustment, and FET Selection
IMPORTANT
JP6 (drain current resistor selection) and JP7 (FET Drain
selection) have jumpers installed that facilitate selection.
The Input Protection selection and the FET Gate selection,
however, have posts to which the user must solder in order
to make the appropriate selection. This is to ensure the best
noise performance. The user must exercise EXTREME
caution while soldering these posts.
Amptek A250CF CoolFET User Manual –Rev. A5
Charge Sensitive Preamplifier
Energy
Output
100
150
200
Time (msec.)
Energy Output
Timing Output
200
300
Time (nsec.)
A250CF CoolFET
Please contact the factory if there are any questions
about the proper selection/soldering procedure.
4.1
FET Selection
The A250CF contains three cooled FETs. FETs 1 and 2 are
low C
=8 pF and FET 3 is high C
iss
2 for low capacitance detectors and FET 3 for high
capacitance detectors (>100 pF).
To select FET 1:
1.
Set TP3 to Pin 5
2.
Set JP7 to jumper 1-2
To select FET 2:
250
1.
Set TP3 to Pin 6
2.
Set JP7 to jumper 3-4
To select FET 3:
1.
Set TP3 to Pin 7
2.
Set JP7 to jumper 5-6
400
Figure 4. Example of FET 1 configuration.
4.2
Drain Current Resistors
JP6 sets the drain current resistor.
selectable resistors.
•
Position 1-2: R34 = 511 Ohms ~ 6 mA
•
Position 3-4: R35 = 348 Ohms ~ 8 mA
•
Position 5-6: R36 = 267 Ohms ~ 10 mA
For low capacitance detectors, R36 typically gives the best
results. As the detector capacitance rises, R35 or R34 may
improve noise performance. The user can adjust these
values for specific applications.
=60 pF. Use FET 1 or
iss
There are three (3)
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