We prepared a short note on how to build a dynode voltage divider network for inexpensive surplus XP2422/SN photomultiplier tubes. The XP2422/SN PMT is especially suited for gamma-ray spectral analysis when coupled to a NaI(Tl) scintillation crystal because of its high pulse-height resolution (PHR). The XP2422/SN is available from Sphere Research in Canada.
Using the $79 SainSmart DSO201 Pocket Oscilloscope and GammaGrapher with the PMT/Scintillation Probe
Connects directly to PMT probe shown in the book’s Figure 30 with no need for PMT amplifier! The nice guys at the Yahoo GammaSpectrometry Group developed multichannel analyzer software for the $79 SainSmart DSO201 Pocket-Sized Digital Oscilloscope. The upload of the MCA software to the oscilloscope is really easy (via USB), and it allows the PMT probe shown in
We built the bulk of our PMT amplifier/processor/discriminator on a Universal PDIP Operational Amplifier Evaluation Module by Texas Instruments (model OPAMPEVM-PDIP). Click on the picture above for a full-size version of the picture. The diagram in the following pdf file shows the connection layout for the circuit shown in the book’s Figure 34: PMT Processor PCB
Figure 34 in the book shows the schematic diagram for the photomultiplier tube (PMT) signal processing circuit that amplifies the narrow pulses detected by the PMT probe. The discriminator stage removes small pulses produced by thermal noise in the tube. A pulse stretcher outputs pulses that can be heard on a speaker. In addition, the analog
The book’s Figure 32 shows the schematic diagram for a low-cost, variable-voltage PMT power supply based on a BXA-12579 inverter module that is originally designed as a power supply for cold-cathode fluorescent lamps. This under-$20 module produces 1,500VAC at around 30kHz from a 12VDC input. We are posting this picture to help you build your own power
This is the datasheet for the RCA 6655A PMT used in the probe shown in the book’s Figure 30: RCA_6655A_Datasheet This is the datasheet for Hamamatsu’s replacement of the RCA 6655A PMT: Hamamatsu replacement for RCA 6655A R2154-02 Schematic diagrams for the probe are in Figure 29.
We are posting this picture to help you construct the variable-output, low-ripple, high-stability, high-voltage power supply described in pages 38-40 of “Exploring Quantum Physics Through Hands-On Projects.” The schematic diagrams for this power supply are in the book’s Figure 31. Output voltage (up to 2 kV) and current (up to 1 mA) are monitored via
A very funny cartoon by Prof. Dr. Claus Grupen of Siegen University: