oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2020 ( 40 )

2019 ( 230 )

2018 ( 278 )

2017 ( 279 )

Custom range...

Search Results: 1 - 10 of 219580 matches for " C. Regenfus "
All listed articles are free for downloading (OA Articles)
Page 1 /219580
Display every page Item
The Argon Dark Matter Experiment (ArDM)
Regenfus, C.
High Energy Physics - Phenomenology , 2008, DOI: 10.3204/DESY-PROC-2008-02/regenfus_christian
Abstract: The ArDM experiment, a 1 ton liquid argon TPC/Calorimeter, is designed for the detection of dark matter particles which can scatter off the spinless argon nuclei. These events producing a recoiling nucleus will be discerned by their light to charge ratio, as well as the time structure of the scintillation light. The experiment is presently under construction and will be commissioned on surface at CERN. Here we describe the detector concept and give a short review on the main detector components.
The Argon Dark Matter Experiment (ArDM)
C. Regenfus
Physics , 2008, DOI: 10.3204/DESY-PROC-2008-02/regenfus_christian
Abstract: The ArDM experiment, a 1 ton liquid argon TPC/Calorimeter, is designed for the detection of dark matter particles which can scatter off the spinless argon nuclei. These events producing a recoiling nucleus will be discerned by their light to charge ratio, as well as the time structure of the scintillation light. The experiment is presently under construction and will be commissioned on surface at CERN. Here we describe the detector concept and give a short review on the main detector components.
High Efficiency Detection of Argon Scintillation Light of 128nm Using LAAPDs
R. Chandrasekharan,A. Knecht,M. Messina,C. Regenfus,A. Rubbia
Physics , 2005,
Abstract: The possibility of efficient collection and detection of vacuum ultraviolet light as emitted by argon, krypton, and xenon gas is studied. Absolute quantum efficiencies of large area avalanche photodiodes (LAAPDs) are derived at these wavelengths. VUV light of wavelengths down to the 128nm of Ar emission is shown to be detectable with silicon avalanche photodiodes at quantum efficiencies above 42%. Flexible Mylar foil overcoated with Al+MgF$_2$ is measured to have a specular reflectivity of $\sim$91% at argon emission wavelength. Low-pressure argon gas is shown to emit significant amounts of non-UV radiation. The average energy expenditure for the creation of non-UV photons in argon gas at this pressure is measured to be below 378 eV.
The Argon Dark Matter Experiment
Christian Regenfus
Physics , 2009, DOI: 10.1088/1742-6596/203/1/012024
Abstract: The ArDM experiment, a 1 ton liquid argon TPC/Calorimeter, is designed for the detection of dark matter particles which can scatter off the spinless argon nucleus, producing nuclear recoils. These events will be discerned by their light to charge ratio, as well as the time structure of the scintillation light. The experiment is presently under construction and commissioning on surface at CERN. Cryogenic operation and light detection performance was recently confirmed in a test run of the full 1 ton liquid argon target under purely calorimetric operation and with a prototype light readout system. This note describes the experimental concept, the main detector components and presents some first results.
Luminescence quenching of the triplet excimer state by air traces in gaseous argon
C. Amsler,V. Boccone,A. Buchler,R. Chandrasekharan,C. Regenfus,J. Rochet
Physics , 2007, DOI: 10.1088/1748-0221/3/02/P02001
Abstract: While developing a liquid argon detector for dark matter searches we investigate the influence of air contamination on the VUV scintillation yield in gaseous argon at atmospheric pressure. We determine with a radioactive alpha-source the photon yield for various partial air pressures and different reflectors and wavelength shifters. We find for the fast scintillation component a time constant tau1= 11.3 +- 2.8 ns, independent of gas purity. However, the decay time of the slow component depends on gas purity and is a good indicator for the total VUV light yield. This dependence is attributed to impurities destroying the long-lived argon excimer states. The population ratio between the slowly and the fast decaying excimer states is determined for alpha-particles to be 5.5 +-0.6 in argon gas at 1100 mbar and room temperature. The measured mean life of the slow component is tau2 = 3.140 +- 0.067 microsec at a partial air pressure of 2 x 10-6 mbar.
Study of nuclear recoils in liquid argon with monoenergetic neutrons
C. Regenfus,Y. Allkofer,C. Amsler,W. Creus,A. Ferella,J. Rochet,M. Walter
Physics , 2012, DOI: 10.1088/1742-6596/375/1/012019
Abstract: For the development of liquid argon dark matter detectors we assembled a setup in the laboratory to scatter neutrons on a small liquid argon target. The neutrons are produced mono-energetically (E_kin=2.45 MeV) by nuclear fusion in a deuterium plasma and are collimated onto a 3" liquid argon cell operating in single-phase mode (zero electric field). Organic liquid scintillators are used to tag scattered neutrons and to provide a time-of-flight measurement. The setup is designed to study light pulse shapes and scintillation yields from nuclear and electronic recoils as well as from {\alpha}-particles at working points relevant to dark matter searches. Liquid argon offers the possibility to scrutinise scintillation yields in noble liquids with respect to the populations of the two fundamental excimer states. Here we present experimental methods and first results from recent data towards such studies.
Tests of silicon sensors for the CMS pixel detector
A. Dorokhov,C. Amsler,D. Bortoletto,V. Chiochia,L. Cremaldi,S. Cucciarelli,M. Konecki,K. Prokofiev,C. Regenfus,T. Rohe,D. Sanders,S. Son,T. Speer,M. Swartz
Physics , 2003, DOI: 10.1016/j.nima.2004.05.050
Abstract: The tracking system of the CMS experiment, currently under construction at the Large Hadron Collider (LHC) at CERN (Geneva, Switzerland), will include a silicon pixel detector providing three spacial measurements in its final configuration for tracks produced in high energy pp collisions. In this paper we present the results of test beam measurements performed at CERN on irradiated silicon pixel sensors. Lorentz angle and charge collection efficiency were measured for two sensor designs and at various bias voltages.
Performance study of the effective gain of the double phase liquid Argon LEM Time Projection Chamber
C. Cantini,L. Epprecht,A. Gendotti,S. Horikawa,L. Periale,S. Murphy,G. Natterer,C. Regenfus,F. Resnati,F. Sergiampietri,A. Rubbia,T. Viant,S. Wu
Physics , 2014, DOI: 10.1088/1748-0221/10/03/P03017
Abstract: The Large Electron Multipliers (LEMs) are key components of double phase liquid argon TPCs. The drifting charges after being extracted from the liquid are amplified in the LEM positioned half a centimeter above the liquid in pure argon vapor at 87 K. The LEM is characterised by the size of its dielectric rim around the holes, the thickness of the LEM insulator, the diameter of the holes as well as their geometrical layout. The impact of those design parameters on the amplification were checked by testing seven different LEMs with an active area of 10$\times$10 cm$^2$ in a double phase liquid argon TPC of 21 cm drift. We studied their response in terms of maximal reachable gain and impact on the collected charge uniformity as well as the long term stability of the gain. We show that we could reach maximal gains of around 150 which corresponds to a signal-to-noise ratio ($S/N$) of about 800 for a minimal ionising particle (MIP) signal on 3 mm readout strips. We could also conclude that the dielectric surfaces in the vicinity of the LEM holes charge up with different time constants that depend on their design parameters. Our results demonstrate that the LAr LEM TPC is a robust concept that is well-understood and well-suited for operation in ultra-pure cryogenic environments and that can match the goals of future large-scale liquid argon detectors.
Position Dependence of Charge Collection in Prototype Sensors for the CMS Pixel Detector
T. Rohe,D. Bortoletto,V. Chiochia,L. M. Cremaldi,S. Cucciarelli,A. Dorokhov,M. Konecki,K. Prokofiev,C. Regenfus,D. A. Sanders,S. Son,T. Speer,M. Swartz
Physics , 2003, DOI: 10.1109/TNS.2004.829487
Abstract: This paper reports on the sensor R&D activity for the CMS pixel detector. Devices featuring several design and technology options have been irradiated up to a proton fluencec of 1E15 n_eq/cm**2 at the CERN PS. Afterward they were bump bonded to unirradiated readout chips and tested using high energy pions in the H2 beam line of the CERN SPS. The readout chip allows a non zero suppressed full analogue readout and therefore a good characterization of the sensors in terms of noise and charge collection properties. The position dependence of signal is presented and the differences between the two sensor options are discussed.
Type inversion in irradiated silicon: a half truth
M. Swartz,D. Bortoletto,V. Chiochia,L. Cremaldi,S. Cucciarelli,A. Dorokhov,M. Konecki,K. Prokofiev,C. Regenfus,T. Rohe,D. A. Sanders,S. Son,T. Speer
Physics , 2004,
Abstract: Charge collection measurements performed on heavily irradiated p-spray dofz pixel sensors with a grazing angle hadron beam provide a sensitive determination of the electric field within the detectors. The data are compared with a complete charge transport simulation of the sensor which includes signal trapping and charge induction effects. A linearly varying electric field based upon the standard picture of a constant type-inverted effective doping density is inconsistent with the data. A two-trap double junction model implemented in ISE TCAD software can be tuned to produce a doubly-peaked electric field which describes the data reasonably well at two different fluences. The modeled field differs somewhat from previous determinations based upon the transient current technique. The model can also account for the level of signal trapping observed in the data.
Page 1 /219580
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.