Browsing by Author "Kowalski, Tadeusz Z."

Now showing 1 - 4 of 4

A comprehensive model of Penning energy transfers in Ar-CO2 mixtures
(IOP Publishing, 2017-06) Kowalski, Tadeusz Z.; Şahin, Özkan; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0003-3940-7222; I-9715-2017; AAH-6445-2021; 36053592700
Ionizing energy transfer mechanisms due to the excited argon atoms, called Penning transfers, have been investigated for various Ar-CO2 mixtures at 0.4, 0.8, 1.2 and 1.8 atm gas pressures. The Penning energy transfer probabilities are extracted from the systematic gas gain measurements carried out in cylindrical proportional counters. In this report, contributions of the several transfer processes are identified by studying the pressure and mixing proportion dependence of the transfer rates with a model.
High-precision gas gain and energy transfer measurements in Ar-CO2 mixtures
(Elsevier, 2014-12-21) Kowalski, Tadeusz Z.; Şahin, Özkan; Veenhof, Robert J.; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0003-3940-7222; AAH-6445-2021; 36053592700; 6603742499
Ar-CO2 is a Penning mixture since a fraction of the energy stored in Ar 3p(5)3d and higher excited states can be transferred to ionize CO2 molecules. In the present work, concentration and pressure dependence of Penning transfer rate and photon feedback parameter in Ar-CO2 mixtures have been investigated with recent systematic high-precision gas gain measurements which cover the range 1-50% CO2 at 400, 800, 1200, 1800 hPa and gas gain from 1 to 5 x 10(5).
Measurements and calculations of gas gain in Xe-5% TMA mixture-pressure scaling
(IOP Publishing, 2018-10) Kowalski, Tadeusz Z.; Şahin, Özkan; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0003-3940-7222; I-9715-2017; AAH-6445-2021; 36053592700
In this work we present both experimental and theoretical investigation of gas gains measured in single anode wire cylindrical counters filled with Xe + 5% TMA (trimethylamine) for the mixture pressures between 250 hPa and 1800 hPa. We observed stable operation at all pressures up to the maximum gas gain values as high as 10(3) (10(4)) at 250 (1800) hPa. The experimental gas gain data have been fitted with the output of Magboltz software to investigate additional ionizations, developing in avalanche formations, due to Penning energy transfers and secondary processes (feedback). Calculations manifest that the choice of TMA as a quench gas have a significant effect on the reachable gas gain. The obtained results are expected to be favourable for micromegas-TPC operating in Xe-TMA mixture.
Systematic gas gain measurements and Penning energy transfer rates in Ne-CO2 mixtures
(IOP Publishing, 2015-12-08) Kowalski, Tadeusz Z.; Şahin, Özkan; Veenhof, Robert J.; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0003-3940-7222; AAH-6445-2021; I-9715-2017; 36053592700; 6603742499
In Ne-CO2 mixtures, excitation energy of Ne atom can be used to ionize CO2 molecule by the mechanisms called Penning transfers. In the present work, we have measured the gas gain systematically in various Ne-CO2 mixtures (Ne + 0 : 6-60 % CO2) at 0.4, 0.8, 1.2, 1.8 atm. The experimental data have been fitted to investigate the Penning energy transfer rates and the secondary processes playing a role in avalanche formations.