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Amptek sets the New State-of-the-Art... Again!
RUN SILENT...RUN FAST...RUN COOL!
The Amptek A250CF "Cool FET" Charge Sensitive Preamplifier is the lowest noise, general purpose, preamplifier
available. It is designed to give the ultimate performance when used with either low or high detector capacitance
detectors and is a direct replacement for other higher noise charge sensitive preamplifiers.
The A250CF "CoolFET" technology uses a thermoelectric (Peltier) cooler to keep the input FET(s) at -50 °C. Cooling
is totally transparent to the user. Hence, the A250CF "CoolFET" operates like a room temperature preamplifier. Based
on the successful A250 designed for high performance satellite instrumentation, the A250CF "CoolFET" re-defines the
new state-of-the-art.
Power to the A250CF "CoolFET" is provided by an external AC power supply (included). Detector bias can be applied
via an SHV connector. Input, Energy (E) Output, Timing (T) Output, and Test are provided via BNC connectors.
100
Low Ciss
High Ciss
10
1
0.1
1
Figure 1. Noise as a function of FET and detector capacitance. D.C. Coupled.
Amptek A250CF CoolFET User Manual –Rev. A5
Charge Sensitive Preamplifier
A250CF CoolFET
with
Cooled
Performance
•
•
•
Features
•
•
•
•
•
•
•
10
Detector Capacitance (pF)
FET
Noise @ 0 pF: 670 eV FWHM (Si)
~76 electrons RMS
Noise Slope:
o
13 eV/pF Low C
o
11.5 eV/pF High C
Fast Rise Time: 2.5 ns
Thermoelectrically Cooled FET
3 FETs to match detector
Lowest Noise and Noise Slope
AC or DC coupling to the detector
Easy to use
Both Energy and Timing outputs
Optional input protection
100
FET
iss
FET
iss
1000
Page 1 of 7
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Table of Contents
Summary of Contents for Amptek CoolFET A250CF
- Page 1 • Optional input protection The Amptek A250CF "Cool FET" Charge Sensitive Preamplifier is the lowest noise, general purpose, preamplifier available. It is designed to give the ultimate performance when used with either low or high detector capacitance detectors and is a direct replacement for other higher noise charge sensitive preamplifiers.
- Page 2 Under normal operation, a high voltage bias is applied The A250CF is a charge sensitive preamplifier. The input across the detector that is used with the Amptek A250CF to the preamplifier is the signal from a radiation detector, a preamplifier.
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Page 3: Specifications
(3) which CoolFET is used. Gain: With a 0.5 pF feedback capacitor and a gain of 2 in the output buffer. 176 mV/MeV (Si) 220 mV/MeV (Ge) 144 mV/MeV (CdTe) Amptek A250CF CoolFET User Manual –Rev. A5 Page 3 of 7... - Page 4 For low capacitance detectors, R36 typically gives the best caution while soldering these posts. results. As the detector capacitance rises, R35 or R34 may improve noise performance. The user can adjust these values for specific applications. Amptek A250CF CoolFET User Manual –Rev. A5 Page 4 of 7...
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Page 5: Ac And Dc Coupling
Figure 6. Shows the protection diode D1 enabled. D1 is Figure X. Shows an AC coupled configuration (H.V. connected to TP3. connected) with the protection resistor disabled (Rp shorted). Amptek A250CF CoolFET User Manual –Rev. A5 Page 5 of 7... -
Page 6: Noise Measurement
NIM electronics amplifiers or the Amptek A275, so that its contribution to the measurement is minimal. The function of the post amplifier is not only to preserve and Amptek A250CF CoolFET User Manual –Rev. - Page 7 Charge Sensitive Preamplifier A250CF CoolFET 7 Schematic (subject to change without notice) Amptek A250CF CoolFET User Manual –Rev. A5 Page 7 of 7...
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