Bochum 2018 – scientific programme
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HK: Fachverband Physik der Hadronen und Kerne
HK 50: Instrumentation XV
HK 50.3: Talk
Thursday, March 1, 2018, 14:45–15:00, Audimax H1
Ar-CF 4 mixtures as counting gas for fission fragments — •Marius Peck1, Joachim Enders1, Alf Göök2, Franz-Josef Hambsch2, and Stephan Oberstedt2 — 1Institut für Kernphysik, TU Darmstadt, Germany — 2European Commission, JRC-IRMM, Geel, Belgium
The use of ionization chambers (IC) for the study of charged particles relies on the accurate determination of the energy deposition in the gas. One of the major issues related to accurate energy determination is the so-called pulse height defect (PHD). The term is used to summarize effects that cause a non-linear response of the pulse height to highly ionizing particles, such as fission fragments. To our knowledge, the only gas for which the PHD has been directly measured with ions of known energies is P-10 (90%Ar + 10%CH 4 ) [1]. However, evidence exists [2] that these results can be directly applied to pure CF 4 . While pure CF 4 has disadvantages due to the very high stopping power, mixing Ar and CF 4 would be more applicable for typical set-ups employed for detecting fission fragments. However for Ar + CF 4 mixtures not much is known in terms of electron mobility and PHD. Hence, counting gas properties in different mixtures of Ar + CF 4 have been studied using a twin Frisch-grid IC. The PHD in the different gas mixtures has been determined relative to the reference gas P-10 using the well-known 252 Cf(sf) decay.
[1] Budtz-Jørgensen, Nucl. Instr. Meth. Phys. Res, Vol. 258, 1987.
[2] Tovesson, J NUCL SCI TECHNOL, Supplement 2, 2002.
Supported by CHANDA and by BMBF (05P15RDENA).