User Manual - NIM Spectroscopy Amplifer and Single Channel Analyser

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This manual was written as part of a student lab exercise in the KJM-FYS 5920 course at the University of Oslo in the autumn 2010.

Quick links: KJM-FYS 5920 Lab Exercise 4 | KJM-FYS 5920 Course

Main author (student): Pejman Mansouri

Co-author (student):

Lab supervisor: Hilde-Therese Nyhus (PhD-student)

Responsible teacher: Prof. Jon Petter Omtvedt

I this experiment a CANBERRA AMP/TSCA model 2015A was used.

The AMP/TSCA or signal amplifier, time single channel analyser is a multi-purpose NIM module. The input signal is a unipolar signal from a pre-amplifier The signal from the pre-amplifier varies in height. The polarity of the input signal should be set by a switch marked as “Input” and +/- on it.

The SCA produces a logical signal whenever the input signal is within a user defined energy window. The energy window is set by two dials in front panel. One is “lower level energy” and the other one is delta-E. Any input signal within this window will generate a logical signal. The logical signal is used for gating.

The logical signals amplitude is independent from the input signals, and is always 5 V. The signal is 500 ns long and is delayed about 200 ns from the top of the amplifier signal. A Gate and Delay module is used to process this signal further before use in a multi channel analyser

The other function of the AMP/TSCA is as an amplifier. The input signal is then
amplified by a factor of up to 1280 times. The amplification is adjusted by two knobs on the front panel: “Gain” and “Fine Gain”. The gain sets the amplification by a fixed factor. The fine gain gives a fine, continuous, adjustment of the amplification in addition to Gain.

This output signal is bipolar signal and is a “slow” signal. While the input signal from a pre-amplifier has a typical rise time of 10-20 ns, the output signal has a rise time of 1-2 mus.
The fall time of a bipolar signal is measured from the tail part (the negative part) of it with the same criteria as a mono polar signal.

On the front panel is a pole zero adjuster marked as “P/Z” and is operated by a screwdriver. The pole zero is seen on the output signal as a hump on the tail of the signal.

The output signal from the amplifier is sent to a amplifier and delay module.