Preamplifiers

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Preamplifiers

GPI GM Pulse Inverter

The GPI Pulse Inverter is designed to interface a Geiger Mueller detector to a nuclear counter requiring positive polarity TTL or NIM logic input. The Pulse Inverter amplifies the negative signal from the GM tube an inverts its polarity producing a positive output signal of 4 volts amplitude and 20 µsec duration.

Power for the GPI is provided from the high voltage supply used to operate the GM tube. Current requirement is about 500 µA. so a high voltage supply with a capacity of at least 1 mA. is recommended. Geiger tubes normally operate in the range of +300 to +1000 volts depending on the specific tube, so the operating plateau should first be run to determine the correct operating voltage.

Connectors on the standard model GPI are as follows:

OUTPUT = BNC, HIGH VOLTAGE = SHV, GM TUBE = MHV.

NOTE: For our GM25 and GM35 detectors, you will either need a BNC cable connector to the GM Tube and an MHV cable connector to the GPI, or, ask us to change the GM Tube input connector to a BNC.

For other connectors, just tell us what you want.

ORDER: GPI GM Pulse Inverter

PA-1 Preamplifier

The PA-1 preamplifier provides a convenient interface between a proportional counter or CdZNTe SPEAR detector and a single or multi-channel analyzer. Due to the low output of these detectors, a preamplifier such as the PA-1 is necessary to measure low energy gamma and X-rays. The PA-1 also provides extra filtering for the high voltage bias. Power is provided for the PA-1 via a DB9 male connector and 3’ cable. The unit is fully compatible with the models UCS20 and UCS30 spectrometers.

Specifications

Bias (SHV Connector): Up to + 2500 Volts.

Power Input (DB9 Male Connecter): Pin 4: +12 Volts @ 10mA

Pin 9: -12 Volts @ 10mA

Pin 1: Ground

Gain: 8mV/KeV, or 7.5mV/pica coulomb

Test Input: 0 to -1V pulse

ORDER: PA-1 Charge Sensitive Preamplifier for use with proportional counters or charged particle detectors