Pulse height distribution of signals produced by exposing a thin GEM chamber to beta rays from an Sr-90 source

B. J. Ahn, Y. J. Ha, C. H. Hahn, S. T. Park, C. Y. Yi, Rena Lee

Research output: Contribution to journalArticlepeer-review


Researchers at Changwon National University's Radiation Detector Development Laboratory(RDD) fabricated a single-channel double-GEM(gas electron multiplier) chamber and measured the pulse height distribution of signals produced by exposing the chamber to an Sr-90 source provided by the Korea Research Institute of Standards and Science(KRISS). A beta-ray electron incident on the GEM chamber ionizes gaseous molecules in the drift region of the chamber by means of electromagnetic interactions. After the leased electrons are amplified by electron avalanches in the GEM stages, the multiplied electrons go from the lowest GEM foil toward the anode of the chamber and induce one signal pulse, corresponding to the incident electron, on the readout pad. The charge signal distribution measured during Sr-90 radioactive source irradiation was compared with the simulation done by using a Landau probability distribution. The energy loss distribution of beta-ray electrons, which deposited part of their energy in a thin GEM chamber while traversing gases within the drift region of that chamber, was in good agreement with the calculation of the Landau probability distribution. The pulse height distributions for energy losses of beta-ray electrons incident on the chamber due to Sr-90 disintegrations were observed in order to select a suitable gas mixture for the chamber. The ratios of the Ar/CO2 gas were 75/25, 80/20, 85/15, and 90/10.

Original languageEnglish
Pages (from-to)1281-1287
Number of pages7
JournalJournal of the Korean Physical Society
Issue number9
StatePublished - May 2014

Bibliographical note

Funding Information:
This work was partially supported by grant No. R01-2006-000-10061-0 from the Basic Research Program of the Korea Science & Engineering Foundation, by the Education & Research Support Program of Changwon National University in 2011∼2012, and by the Nuclear Power Core Technology Development Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20131510400050). Our experiment using an Sr-90 radiation source was performed by the Ionizing Radiation Team at the Korea Research Institute of Standard and Science in 2006. We appreciate Professor S. N. Kim at the Department of Physics Education, Korea National University of Education for his courtesy in providing the experimental equipment.


  • Bethe-Bloch formula
  • Fermi beta decay theory
  • Landau probability distribution
  • Pulse height distribution
  • Single-channel double-GEM chamber
  • Sr-90 source


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