Methods for detecting events in double-phase argon chambers

• Published in: Instruments and experimental techniques (New York) 2013-09, Vol.56 (5), p.516-520
• Main Authors: Ovchinnikov, B. M., Parusov, V. V.
• Format: Article
• Language: English
• Subjects: Electrical Engineering; Measurement Science and Instrumentation; Nuclear Experimental Techniques; Physical Chemistry; Physics; Physics and Astronomy
• ISSN: 0020-4412; 1608-3180
• DOI: 10.1134/S0020441213050072

Multichannel wire gas electron multipliers in combination with pin anodes are proposed for detection of events in the gas phase of a double-phase argon chamber. Hydrogen with a concentration of 10 vol % is added to argon to eliminate feedbacks by photons emitted by excited argon molecules in avalanche development processes while detecting events in the argon gas. A maximum electron multiplication coefficient of ∼300 has been obtained for the multichannel wire gas electron multipliers with a 1-mm gap used to detect α particles in the Ar + 10% H 2 mixture at a pressure of 1 atm (abs.). When a pin anode is used, the maximum electron multiplication factor is ∼2.5 × 10 5 for α particles and 3 × 10 6 for β particles ( 63 Ni). It has been experimentally shown that adding H 2 with a concentration of 100 ppm to liquid argon has no effect on the singlet component of the scintillation signal in the liquid argon and reduces the emission efficiency relative to the pure argon gas phase only slightly (by 20%).