Browsing by Author "Veenhof, Rob"

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Charged particle timing at sub-25 picosecond precision: The picosec detection concept
(Elsevier, 2019-08-21) Iguaz, F. J.; Bortfeldt, J.; Brunbauer, F. M.; David, C.; Desforge, D.; Fanourakis, G.; Franchi, J.; Gallinaro, M.; Garcia, F.; Giomataris, I; Gonzalez-Diaz, D.; Gustaysson, T.; Guyot, C.; Kebbiri, M.; Legou, P.; Liu, J.; Lupberger, M.; Maillard, O.; Manthos, I; Mueller, H.; Niaouris, V; Oliveri, E.; Papaevangelou, T.; Paraschou, K.; Pomorskif, M.; Qi, B.; Resnati, F.; Ropelewski, L.; Sampsonidis, D.; Schneider, T.; Schwemling, P.; Sohl, L.; van Stenis, M.; Thuiner, P.; Tsipolitis, Y.; Tzamarias, S. E.; Wang, X.; White, S.; Zhang, Z.; Zhou, Y.; Veenhof, Rob; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.
The PICOSEC detection concept consists in a "two-stage" Micromegas detector coupled to a Cherenkov radiator and equipped with a photocathode. A proof of concept has already been tested: a single-photoelectron response of 76 ps has been measured with a femtosecond UV laser at CEA/IRAMIS, while a time resolution of 24 ps with a mean yield of 10.4 photoelectrons has been measured for 150 GeV muons at the CERN SPS H4 secondary line. This work will present the main results of this prototype and the performance of the different detector configurations tested in 2016-2018 beam campaigns: readouts (bulk, resistive, multipad) and photocathodes (metallic+CsI, pure metallic, diamond). Finally, the prospects for building a demonstrator based on PICOSEC detection concept for future experiments will be discussed. In particular, the scaling strategies for a large area coverage with a multichannel readout plane, the R&D on solid converters for building a robust photocathode and the different resistive configurations for a robust readout.
Impact of gem foil hole geometry on gem detector gain
(Iop Publishing Ltd, 2015-12-01) Karadzhinova, A.; Nolvi, A.; Veenhof, Rob; Tuominen, E.; Haeggstrom, E.; Kassamakov, I.; Veenhof, Rob; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü; GJK-8031-2022
Detailed 3D imaging of Gas Electron Multiplier (GEM) foil hole geometry was realized. Scanning White Light Interferometry was used to examine six topological parameters of GEM foil holes from both sides of the foil. To study the effect of the hole geometry on detector gain, the ANSYS and Garfield ++ software were employed to simulate the GEM detector gain on the basis of SWLI data. In particular, the effective gain in a GEM foil with equally shaped holes was studied. The real GEM foil holes exhibited a 4% lower effective gain and 6% more electrons produced near the exit electrode of the GEM foil than the design anticipated. Our results indicate that the GEM foil hole geometry affects the gain performance of GEM detectors.
Progress on the PICOSEC-micromegas detector development: Towards a precise timing, radiation hard, large-scale particle detector with segmented readout
(Elsevier, 2020-04-01) Kordas, K.; Bortfeldt, J.; Brunbauer, F.; David, C.; Desforge, D.; Fanourakis, G.; Franchi, J.; Gallinaro, M.; Garcia, F.; Giomataris, I.; Gonzalez-Diaz, D.; Gustavsson, T.; Guyot, C.; Iguaz, F. J.; Kebbiri, M.; Legou, P.; Liu, J.; Lupberger, M.; Maillard, O.; Maniatis, I.; Manthos, I.; Mueller, H.; Niaouris, V.; Oliveri, E.; Papaevangelou, T.; Paraschou, K.; Pomorski, M.; Qi, B.; Resnati, F.; Ropelewski, L.; Sampsonidis, D.; Schneider, T.; Schwemling, P.; Sohl, L.; van Stenis, M.; Thuiner, P.; Tsipolitis, Y.; Tzamarias, S. E.; Veenhof, R.; Wang, X.; White, S.; Zhang, Z.; Zhou, Y.; Veenhof, Rob; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; GJK-8031-2022
This contribution describes the PICOSEC-Micromegas detector which achieves a time resolution below 25 ps. In this device the passage of a charged particle produces Cherenkov photons in a radiator, which then generate electrons in a photocathode and these photoelectrons enter a two-stage Micromegas with a reduced drift region and a typical anode region. The results from single-channel prototypes (demonstrating a time resolution of 24 ps for minimum ionizing particles, and 76 ps for single photoelectrons), the understanding of the detector in terms of detailed simulations and a phenomenological model, the issues of robustness and how they are tackled, and preliminary results from a multi-channel prototype are presented (demonstrating that a timing resolution similar to that of the single-channel device is feasible for all points across the area covered by a multi-channel device).
Protonated water clusters in TPC's
(Elsevier, 2016-07-11) Kaya, Yunus; Kalkan, Yalçın; Veenhof, Rob; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0001-8469-8132; 0000-0001-7407-1635; AAH-3852-2020; GXH-7079-2022; 35181446100; 56736206100; 6603742499
Water vapour is added to the ALICE TPC gas to enhance its stability. These polar molecules create large protonated water clusters around a H+ core. In this context, the reactions H3O+ (H2O)(n-1) + H2O -> H-3 O+(H2O)(n) (n=1-9) were studied in the gas phase. Structures for these clusters are suggested and the most stable structures for each cluster size are shown. The thermodynamic parameters Delta H-n-1,n(0), Delta G(n-1,n)(0), Delta S-n-1,n(0) and equilibrium constants K-n-1,K-n for the reaction were calculated to determine the size of the water clusters. The results are close to experimental data found in the literature. Protonated water clusters at stp have a size of 6-9 which corresponds to a mass of 127.1-181.2 g/mole.
Timing performance of a micro-channel-plate photomultiplier tube
(Elsevier, 2020-04-21) Bortfeldt, J.; Brunbauer, F.; David, C.; Desforge, D.; Fanourakis, G.; Gallinaro, M.; Garcia, F.; Giomataris, I; Gustavsson, T.; Guyot, C.; Iguaz, F. J.; Kebbiri, M.; Kordas, K.; Legou, P.; Liu, J.; Lupberger, M.; Manthos, I; Mueller, H.; Niaouris, V; Oliveri, E.; Papaevangelou, T.; Paraschou, K.; Pomorski, M.; Resnati, F.; Ropelewski, L.; Sampsonidis, D.; Schneider, T.; Schwemling, P.; Scorsone, E.; Sohl, L.; van Stenis, M.; Thuiner, P.; Tsipolitis, Y.; Tzamarias, S. E.; Veenhof, R.; Wang, X.; White, S.; Zhang, Z.; Zhou, Y.; Veenhof, Rob; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü; GJK-8031-2022
The spatial dependence of the timing performance of the R3809U-50 Micro-Channel-Plate PMT (MCP-PMT) by Hamamatsu was studied in high energy muon beams. Particle position information is provided by a GEM tracker telescope, while timing is measured relative to a second MCP-PMT, identical in construction. In the inner part of the circular active area (radius r<5.5 mm) the time resolution of the two MCP-PMTS combined is better than 10 ps. The signal amplitude decreases in the outer region due to less light reaching the photocathode, resulting in a worse time resolution. The observed radial dependence is in quantitative agreement with a dedicated simulation. With this characterization, the suitability of MCP-PMTS as t(0) reference detectors has been validated.
Understanding avalanches in a Micromegas from single-electron response measurement
(Elsevier, 2015-02-01) Zerguerras, T.; (Genolini, B.; Kuger, F.; Josselin, M.; Maroni, A.; Nguyen-Trung, T.; Pouthas, J.; Rosier, P.; Suzuki, D.; Şahin, Özkan; Veenhof, Rob; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Fizik Bölümü.; 0000-0003-3940-7222; AAH-6445-2021; GJK-8031-2022; 36053592700; 6603742499
Avalanche fluctuations set a limit to the energy and position resolutions that can be reached by gaseous detectors. This paper presents a method based on a laser test bench to measure the absolute gain and the relative gain variance of a Micro Pattern Gaseous Detector from its single electron response. A Micromegas defector was operated with three binary gas mixtures, composed of 5% isobuLane as a quencher, with argon, neon or helium, at atmospheric pressure. The anode signals were read our by low noise, high gain CremaL CR-110 charge preamplifiers to enable single electron defection down to gain of 5 x 10(3) for the first Lime. The argon mixture shows the lowest gain at a given amplification field together with the lowest breakdown limit, which is at a gain of 2 x 10(4) an order of magnitude lower than that of neon or helium. For each gas, the relative gain variance f is almost unchanged in the range of amplification field studied, It was found that f is twice higher (f similar to 0.6) in argon than in the two other mixtures. This hierarchy of gain and relative gain variance agrees with predictions of analytic models, based on gas ionisation yields, and a Monte-Carlo model included in the simulation software Magboltz version 10.1.