Free ion yield of Trimethyl Bismuth used as sensitive medium for $\gamma$ detection
| Autor: | Farradèche, M., Tauzin, G., J-Ph. Mols, J-P, Dognon, Dauvois, V., Viatcheslav Sharyy, J-P, Bard, Mancardi, X., Verrecchia, P., Yvon, D. |
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| Přispěvatelé: | Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), HEP, INSPIRE |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | HAL JINST JINST, 2018, 13 (11), pp.P11004 |
| Popis: | International audience; CaLIPSO project is an innovative {\gamma} detector concept using trimethylbismuth as sensitive medium in a liquid ionization chamber. The detector, designed for high precision brain PET imaging, works as a time-projection chamber and detects both ionization and Cherenkov light signals. In order to characterize the detector, we measured the free ion yield of trimethylbismuth and tetramethylsilane, used as a reference liquid, by measuring the current induced by a $^{60}$Co source in an ionization chamber. We measured a zero-field free ion yield of $0.53 \pm 0.03$ for tetramethylsilane, in agreement with measurements in literature. For trimethylbismuth, the zero-field free ion yield is $0.083 \pm 0.003$, which is a factor 7 lower than the typical values for similar dielectric liquids. Quantum chemical computations on heavy atoms tend to demonstrate a high capacity of TMBi to capture electrons which could explain the discrepancy. The consequences of a low free ion yield in terms of {\gamma} detection and brain PET imaging are finally discussed. |
| Databáze: | OpenAIRE |
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