Naslov
Statistical fluctuations in gas amplification factor of a low-pressure proportional counter

Autori
Krajcar Bronić, Ines ; Grosswendt, Bernd

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
Proceedings of the IRPA Regional Congress on Radiation Protection in Central Europe: Radiation protection and Health / Obelić, B; Ranogajec-Komor, M; Miljanić, S; Krajcar Bronić, I - Zagreb : Hrvatsko društvo za zaštitu od zračenja, 2002, 8p-17

Skup
IRPA Regional Congress on Radiation Protection in Central Europe: Radiation protection and Health

Mjesto i datum
Dubrovnik, Hrvatska, 20.05.2001. - 25.05.2001

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
proportional counter; gas amplification

Sažetak
The electron avalanche formation in low-pressure (2 kPa - 90 kPa) argon-based gas mixtures in strong non-uniform electric fields was studied by a proportional counter. Concentration of admixtures (propane, isobutane, DME) varied between 1% and 80%. The relative variance f of the avalanche size distribution was determined by measuring single-electron (SE) spectra. In pure gases and in mixtures with high content of the admixture, the SE spectra had always a peaked distribution, f<1, although f increased with M. In "thin" mixtures the SE spectra changed the shape to the over-exponential distribution, f>1. The f value depended on the partial pressure p of the admixture. The gas gain where the SE spectra change their shape, f~1, is roughly equal to the gain M0 where over-exponential increase of gas gain started. Both effects in M and f are caused by avalanche chain formation due to insufficient quenching of the admixture. Energy resolution above M0 in "thin" mixtures degraded very quickly. Partial pressure should be above ~10 kPa to assure good quenching even at the highest gains obtained in the present experiment.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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