Overview
Canberra is a company that specializes in radiation / nuclear instrumentation. This unit comprised of a ‘Nuclear Instrument Module’ (NIM) and a data acquisition unit (essentially a basic computer and an ADC). The NIM is part of a gamma spectrometer unit.
This unit supplies the high voltage going to the scintillator and converts output signal into square-shaped pulses with amplitudes varying depending on the energy of the impacted particle. This gets passed onto the ADC which sorts each sample into bins. The resultant spectrum looks like the cobalt-60 spectrum shown in the image below. More information can be found at https://en.wikipedia.org/wiki/Gamma_spectroscopy.
The modules in the NIM are…
- H.V. Power Supply Model 3102
- AMP/TSCA Model 2015A
- Nuclear Counter Model 1775
- LIN/LOG Ratemeter Model 1481LS
- Spectrum Stabilizer Model 2050
- Spectroscopy Amplifier Model 2010
- H.V Power Supply Model 3002
- NIM BIN Power Supply Model 2000
Teardown
Part 1:
Part 2:
NIM BIN Power Supply
This unit is located behind the modules. The output voltages from this unit are ±24V, ±12V, and 115VAC. The datasheet for this unit can be found here an updated model can be found here. This unit can output 72W of power using a linear supply with a ripple of less than 3mV.
High Voltage Power Supply – Model 3102
This supply’s datasheet can be found here. This supply can output ±2kV with a ripple of under 2mV pk-pk. Its temperature coefficient is 50ppm/ °C. The ICs in this unit are the CA3240E opamp, and TL082CP opamp,
The output polarity of the supply can be changed by flipping over the reversal plug.
AMP/TSCA – Model 2015A
The datasheet for this module can be found here and the updated module can be found here. The datasheet says it “optimizes energy resolution in spectroscopy applications with Ge and Si detectors”
LIN/LOG Ratemeter Model 1481LS
The datasheet for an updated module can be found here.This ratemeter displays the number of pulses per second that are coming from the scintillator on a log and linear scale. This board has a mod board installed which changes the scale on the Time Constant dial.
Spectrum Stabilizer Model 2050
The datasheet could not be found for this module. It could be doing analog signal processing.
Spectroscopy Amplifier Model 2010
The datasheet for this unit was not found. The datasheet for the updated unit can be found here.
High Voltage Power Supply Model 3002
The manual for this power supply can be found here. It can output up to ±3kVDC with a current output of up to 10mA. It uses safe high voltage BNC like connectors to transmit this high voltage. More information about these type of connectors can be found here. The noise performance of this supply is 10mV pk-pk, slightly higher than the model 3102 HV power supply performance of 2mV pk-pk. Both are very accurate supplies. It is uncommon that a DC-DC converter has this low of ripple.
In the potted region, there is a high voltage transformer, rectifier, ripple filter, and feedback resistor divider circuit.
