Low-level beta GM multicounter


Low level Beta Counter 


Low-level gas flow beta multicounter system for the measurement of 5 samples simultaneously.
The basic part of the Risø low-level beta multicounter system is a gas-flow unit with dimensions of 50x100x250 mm which incorporates five individual GM sample counter elements and a common guard counter.
The guard counter reduces the cosmic-ray background by using anticoincidence technique. Each sample counter element is provided with an aluminized Mylar window of density < 1 mg/cm2 and diameter 25 mm. The counters are gas-flow types designed for 99 % Ar/1 % isobutane or 99 % Ar/1% propane counter gas. A sample slide allows five samples to be inserted into the multicounter. These samples are measured simultaneously. A lift mechanism minimizes the sample-to-window distance to obtain optimal efficiency. The multicounter is normally placed inside a lead shielding of 100 mm thickness to reduce the ambient background radiation.



  • Sample size: 25 mm diameter.
  • Counter gas: 99% Argon N48/1% Isobutane N25 (or 99% Argon/1% propane N25).
  • Sample counter elements: 25 mm diameter with aluminized mylar window (<1 mg/cm2).
  • Guard counter: 100 mm x 250 mm x 12 mm.
  • Background in 100 mm lead shieldine: <0.2 CPM (typically <0.15 CPM.
  • Efficiency: 90Sr/Y (activity prepared on a 25 mm diameter filterpaper attached to a 5 mm thick Thallium disc): 54%. 36Cl (activity deposited on a 25 mm. diameter x 5 mm thick plastic disc): 44%. 14 C (1 mm. thick acrylic source, 25 mm diameter): 24%.
  • 99Tc (Electro plated on steel disc): 42%.
  • Size: Mechanical unit: 50 x 100 x 250 mm. (Other dimensions on request) disc./anticoincidense module: 250x250x65 mm.


External USB interface 


USB upgrade
An external USB interface is now available for the Risoe beta multicounter, replacing the original PC-card. This now allows the use of a laptop computer to control the counter.
The new system can run up to 4 counters simultaneously, on the same pc. A new improved version of the software is available with the new interface.


Software update
An update of the software running the beta counter is available for download here

Contact concerning instruments

For further product information, 

mail: osl@ntech.dtu.dk

For technical support,

mail: oslservice@ntech.dtu.dk

Product Catalogue

Radiation Instruments

  • Risø TL/OSL Reader
  • Ultra-low-level Beta GM Multicounter
  • Risø gamma spectrometry system

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