Searching for an alpha-sensible Geiger tube to buy, you’ll find for sure some Si8B and SBT11 pancale style tubes. This are great tubes but… if you found this MST17? It’s not a military surplus pancake tube, is from the professional series “M”. You must know that russian tubes that name starts with “M” are made for professional and scientific use. Usualy are made in glass and are fragile, they need higher voltage to operate but…. they are true scientific tools not cheap surplus!
This is the MST17 tube, a professional tube used by russian in professional scientific equipment. Is cheaper than other mica windowed tubes because il hard to use. It need 1600V in order to operate. It was used to measure milk nuclear contamination after Cernobyl disaster in contamined ukrainian zones.
The tube have a metal cap to protect the mica window and to filter out most od Alpha particles, i say “most” and not all because it have a small hole in the center. The mica window is not so thin so I think this tube is more suitable to beta and gamma use.
I’ve found some other infos about this tube:
- Radiation determine:
- Alpha *
- Beta (>0.16Mev)
*- the distance between source and mica window must be 25 mm or less (for alpha radiation only).
- Voltage of start of counting: < 1600V
- Operating voltage (recommended): 1620 – 1740V
- Length of flat part of counting curve (plateau): 150 V
- Slope of the counting curve: < 0.05%
- Own background: < 0.41 counts/s
- Maximum radiation: 10,000 counts/min
- Load resistance: 7-10 MOhm
- Allowable stray input capacitance: < 10 pF
- Working temperature range: -30…+50 C
- Anode material: Platinum
- Mica window thickness: < 5 mg/cm2
- Weight: ~20g
- Dimensions: counter length 100mm, diameter 40mm
- Mica window diameter: 20 mm.
The DP100 russian scientific instrument use the MST17, enclosed into a lead chamber to reduce background radiation, to mesure milk contamination.
In this paper mst17_paper “MONTE CARLO MODELING OF BETA RADIOMETER DEVICE
USED TO MEASURE MILK CONTAMINATED AS A RESULT OF THE
CHERNOBYL ACCIDENT” there is a physical modelling and mathematical analysis of this device.