We present pulse height measurements in drift chambers operated with Xe,CO2 gas mixtures. We investigate the attachment of primary electrons on oxygen and SF6 contaminants in the detection gas. The measurements are compared with simulations of properties of drifting electrons. We present two methods to check the gas quality: gas chromatography and Fe55 pulse height measurements using monitor detectors.
Air-ionization chambers have been used in radiotherapy and particle therapy for decades. However, fundamental parameters in action in the detector responses are sparsely studied. In this work we aimed to measure the electronic attachment, electrons and ions mobilities of an ionization chamber (IC) in air. The main idea is to extract these from the actual response of the IC to a single ionizing particle in order to insure that they were measured in the same condition they are to be used while neglecting undesired phenomena: recombination and space charge effect. The non-standard signal shape an…
We present measurements of position and angular resolution of drift chambers operated with a Xe,CO$_2$(15%) mixture. The results are compared to Monte Carlo simulations and important systematic effects, in particular the dispersive nature of the absorption of transition radiation and non-linearities, are discussed. The measurements were carried out with prototype drift chambers of the ALICE Transition Radiation Detector, but our findings can be generalized to other drift chambers with similar geometry, where the electron drift is perpendicular to the wire planes.
We present measurements of the energy loss of pions and electrons in drift chambers operated with a Xe,CO2(15%) mixture. The measurements are carried out for particle momenta from 1 to 6 GeV/c using prototype drift chambers for the ALICE TRD. Microscopic calculations are performed using input parameters calculated with GEANT3. These calculations reproduce well the measured average and most probable values for pions, but a higher Fermi plateau is required in order to reproduce our electron data. The widths of the measured distributions are smaller for data compared to the calculations. The elec…
Using prototype modules of the ALICE Transition Radiation Detector we investigate space charge effects and the dependence of the pion rejection performance on the incident angle of the ionizing particle. The average pulse height distributions in the drift chambers operated with the Xe,CO2(15%) mixture provide quantitative information on the gas gain reduction due to space charge accumulating during the drift of the primary ionization. Our results demonstrate that the pion rejection performance of a TRD is better for tracks which are not at normal incidence to the anode wires. We present detail…
The operations of Resistive Plate Chambers in LHC experiments require Fluorine based (F-based) gases for optimal performance. Recent European regulations demand the use of environmentally unfriendly F-based gases to be limited or banned. In view of the CMS experiment upgrade, several tests are ongoing to measure the performance of the detector with these new ecological gas mixtures, in terms of efficiency, streamer probability, induced charge and time resolution. Prototype chambers with readout pads and with the standard CMS electronic setup are under test. In this paper preliminary results on…
Systematic measurements on the rate capability of thin MWPCs operated in Xenon, Argon and Neon mixtures using CO2 as UV-quencher are presented. A good agreement between data and existing models has been found, allowing us to present the rate capability of MWPCs in a comprehensive way and ultimately connect it with the mobilities of the drifting ions.
A micro time-projection-chamber (micro-TPC) with a detection volume of 23*28*31 cm^3 was developed, and its fundamental performance was examined. The micro-TPC consists of a micro pixel chamber with a detection area of 31*31 cm^2 as a two-dimensional imaging device and a gas electron multiplier with an effective area of 23*28 cm^2 as a pre-gas-multiplier. The micro-TPC was operated at a gas gain of 50,000, and energy resolutions and spatial resolutions were measured.
The low cost and high resolution Multi-gap Resistive Plate Chamber (MRPC) opens up a new possibility to find an efficient alternative detector for the Time of Flight (TOF) based Positron Emission Tomography, where the sensitivity of the system depends largely on the time resolution of the detector. In a layered structure, suitable converters can be used to increase the photon detection efficiency. In this paper results of the cosmic ray test of a four-gap bakelite-based prototype MRPC operated in streamer mode and six-gap glass-based MRPC operated in avalanche mode are discussed.
The requirement of high rate capability for operation at LHC, led 20 years ago to the achievement of Resistive Plate Chambers operated in avalanche mode, thanks to the introduction of new gas mixtures and to the development of the Front-End electronics. The need for a further increase of the rate capability, in view of the upgrades of LHC, is imposing new detector geometries with thinner gas gaps and electrodes. Streamer operation of RPCs may still be suitable for low rate experiments, and therefore in this paper a comparison between two different detector geometries, the old standard and the …
We successfully operated a novel kind of LAr Time Projection Chamber based on a Large Electron Multiplier (LEM) readout system. The prototype, of about 3 liters active volume, is operated in liquid-vapour (double) phase pure Ar. The ionization electrons, after drifting in the LAr volume, are extracted by a set of grids into the gas phase and driven into the holes of a double stage LEM, where charge amplification occurs. Each LEM is a thick macroscopic hole multiplier of 10x10 cm$^2$ manufactured with standard PCB techniques. The electrons signal is readout via two orthogonal coordinates, one u…
This communication describes test beam results, focusing on detection efficiency and timing precision, of common float glass timing Resistive Plate Chambers (tRPCs) exposed to a $2.7$~GeV proton beam and operated at above ambient temperature in order to increase the count rate capability of the chambers, by exploiting the reduction in the resistivity of the glass electrodes. Results suggest that the count rate capability can be extended at least up to $1500~Hz/cm^2$ when the detector is operated at $40.6^{\circ}$C without noticeable loss of efficiency or timing precision degradation with value…
Studies of the performance of the CMS drift tube barrel muon system are described, with results based on data collected during the CMS Cosmic Run at Four Tesla. For most of these data, the solenoidal magnet was operated with a central field of 3.8 T. The analysis of data from 246 out of a total of 250 chambers indicates a very good muon reconstruction capability, with a coordinate resolution for a single hit of about 260 microns, and a nearly 100% efficiency for the drift tube cells. The resolution of the track direction measured in the bending plane is about 1.8 mrad, and the efficiency to re…
Drift chambers operated with helium-based gas mixtures represent a common solution for tracking charged particles keeping the material budget in the sensitive volume to a minimum. The drawback of this solution is the worsening of the spatial resolution due to primary ionisation fluctuations, which is a limiting factor for high granularity drift chambers like the MEG II tracker. We report on the measurements performed on three different prototypes of the MEG II drift chamber aimed at determining the achievable single-hit resolution. The prototypes were operated with helium/isobutane gas mixture…
The liquid argon time projection chamber provides high resolution event images and excellent calorimetric resolution for studying neutrino physics and searching for beyond standard model physics. In this article, we review the main physics processes that affect the detector response, including the electronics and field responses, space charge effects, electron attachment to impurities, diffusion and recombination. We describe methods to measure those effects, which are used to calibrate the detector response and convert the measured raw ADC counts to the original energy deposition.
Time Projection Chambers (TPCs) operated at high pressure have become a topic of interest for future long baseline neutrino experiments. Pressurized gas retains the low momentum threshold for particle detection of atmospheric TPCs, but offers a larger target mass for neutrino interactions at the same volume. Operation at high pressure poses several new challenges in safety aspects regarding overpressure and high voltage safety. The presented High Pressure Gas Monitoring Chamber (HPGMC) can be used to study the suitability of various drift gas mixtures up to 10 bar and a maximum field of $\sim$…
We report on the first steps in the development of a small-size muon telescope based on glass Resistive Plate Chambers with small active area ($16\times 16~{\rm cm}^2$). The long-term goal of this project is to focus on applications of muography where the telescope may have to be operated underground and/or inside small rooms, and in challenging logistic situations. Driving principles in our design are therefore compact size, light weight, gas tightness, and robustness. The first data-taking experiences have been encouraging, and we elaborate on the lessons learnt and future directions for dev…
XeBRA is a flexible cryogenic platform designed to perform research and development for liquid xenon detectors searching for rare events. Its extra-large outer cryostat makes it possible to install a wide variety of detector designs. We present the system, including its cryogenic, gas handling, data acquisition and slow control subsystems. Two dual phase time projection chambers with sensitive masses at the 1 kg scale have so far been operated in XeBRA. Using data from these, we determine the field-dependence of the electron drift velocity in liquid xenon. We also measure the relative charge a…
The ICARUS Collaboration has operated successfully the Liquid Argon time projection chamber (LAr-TPC), a novel and continuously sensitive bubble chamber like neutrino detector in the GranSasso Laboratory and an underground neutrino beam coming from the CERN-SPS. ICARUS may now be moved at the 8 GeV FNAL-Booster for a search of LSND-like neutrino-electron anomalies at a shallow depth and shorter distance from the target, where three experiments will simultaneously study neutrinos at three different locations. New and substantial modifications are described in order to make ICARUS operable in th…
In view of a possible application as a charge-particle track readout for an Active-Target Time Projection Chamber (AT-TPC), the operational properties and performances of a hybrid Micro-Pattern Gaseous Detector (MPGD) were investigated in pure low-pressure Hydrogen (H2) and Helium (He). The detector consists of a MICROMesh GAseous Structure (MICROMEGAS) coupled to a single- or multi-cascade THick Gaseous Electron Multiplier (THGEM) as a pre-amplification stage. This study reports of the effective gain dependence of the hybrid-MPGD at relevant pressure (in the range of 200-760 torr) for differe…
We have operated a liquid-argon large-electron-multiplier time-projection chamber (LAr LEM-TPC) with a large active area of 76 $\times$ 40 cm$^2$ and a drift length of 60 cm. This setup represents the largest chamber ever achieved with this novel detector concept. The chamber is equipped with an immersed built-in cryogenic Greinacher multi-stage high-voltage (HV) multiplier, which, when subjected to an external AC HV of $\sim$1 kV$_{\mathrm{pp}}$, statically charges up to a voltage a factor of $\sim$30 higher inside the LAr vessel, creating a uniform drift field of $\sim$0.5 kV/cm over the ful…
Measurements and numerical simulations on the charge transfer in Gas Electron Multiplier (GEM) foils are presented and their implications for the usage of GEM foils in Time Projection Chambers are discussed. A small test chamber has been constructed and operated with up to three GEM foils. The charge transfer parameters derived from the electrical currents monitored during the irradiation with an Fe-55 source are compared with numerical simulations. The performance in magnetic fields up to 2 T is also investigated.
The DeeMe experiment to search for muon-to-electron conversions with a sensitivity 10--100 times better than those achieved by previous experiments is in preparation at the Japan Proton Accelerator Research Complex. The magnetic spectrometer used by the DeeMe experiment consists of an electromagnet and four multiwire proportional chambers (MWPCs). The newly developed MWPCs are operated with a high voltage (HV) switching technique and have good burst-hit tolerance. In this article, the final designs of the MWPCs, amplifiers for readout, and HV switching modules are described. Additionally, some…
Calibration of the discriminator threshold of the Amplifier-Shaper-Discriminator Chip for the Upgrade of the ATLAS Muon Drift-Tube Chambers for the High-Luminosity LHC
The HERA-B Outer Tracker is a large system of planar drift chambers with about 113000 read-out channels. Its inner part has been designed to be exposed to a particle flux of up to 2.10^5 cm^-2 s^-1, thus coping with conditions similar to those expected for future hadron collider experiments. 13 superlayers, each consisting of two individual chambers, have been assembled and installed in the experiment. The stereo layers inside each chamber are composed of honeycomb drift tube modules with 5 and 10 mm diameter cells. Chamber aging is prevented by coating the cathode foils with thin layers of co…
The reconstruction of the positron trajectory in the MEG-II experiment searching for the $μ^+ \to e^+ γ$ decay uses a cylindrical drift chamber operated with a helium-isobutane gas mixture. A stable performance of the detector in terms of its electron drift properties, avalanche multiplication, and with a gas mixture of controlled composition and purity has to be provided and continuously monitored. In this paper we describe the strategies adopted to meet the requirements imposed by the target sensitivity of MEG-II, including the construction and commissioning of a small chamber for an online …
The performance of a small prototype of a cylindrical drift chamber (CDC) used in the COMET Phase-I experiment was studied by using an electron beam. The prototype chamber was constructed with alternating all-stereo wire configuration and operated with the He-iC$_{4}$H$_{10}$ (90/10) gas mixture without a magnetic field. The drift space-time relation, drift velocity, d$E$/d$x$ resolution, hit efficiency, and spatial resolution as a function of distance from the wire were investigated. The average spatial resolution of 150 $μ$m with the hit efficiency of 99% was obtained at applied voltages hig…
We constructed and operated a double phase (liquid-vapour) pure argon Large Electron Multiplier Time Projection Chamber (LAr LEM-TPC) with a sensitive area of 10x10 cm$^2$ and up to 30 cm of drift length. The LEM is a macroscopic hole electron multiplier built with standard PCB techniques: drifting electrons are extracted from the liquid to the vapour phase and driven into the holes of the LEM where the multiplication occurs. Moving charges induce a signal on the anode and on the LEM electrodes. The orthogonally segmented upper face of the upper LEM and anode permit the reconstruction of X-Y s…
The identification of single clusters in the electronic signals produced by ionizing particles within a drift chamber is expected to significantly improve the performances of this kind of detectors in terms of particle identification capabilities and space resolution. In order to develop refined cluster recognition algorithms, it is essential to measure the response of the chamber and its electronics to single ionization clusters. This can be done by irradiating the chamber with X-rays. We report here on the studies performed on a drift chamber prototype for the MEG-II experiment at the X-ray …
The PandaX-III (Particle And Astrophysical Xenon Experiment III) experiment will search for Neutrinoless Double Beta Decay (NLDBD) of 136Xe at the China Jin-Ping underground Laboratory II (CJPL-II). In the first phase of the experiment, a high pressure gas Time Projection Chamber (TPC) will contain 200 kg, 90% 136Xe enriched gas operated at 10 bar. Microbulk Micromegas, a fine pitch micro-pattern gas detector, will be used for charge readout and enable us to reconstruct tracks of NLDBD events with good energy and spatial resolution. With simulation, we demonstrate excellent background suppress…
For the muon spectrometer of the ATLAS detector at the large hadron collider (LHC), large drift chambers consisting of 6 to 8 layers of pressurized drift tubes are used for precision tracking covering an active area of 5000 m2 in the toroidal field of superconducting air core magnets. The chambers have to provide a spatial resolution of 41 microns with Ar:CO2 (93:7) gas mixture at an absolute pressure of 3 bar and gas gain of 2?104. The environment in which the chambers will be operated is characterized by high neutron and background with counting rates of up to 100 per square cm and second. T…
Since the summer of 2003, a large Micromegas TPC prototype (1000 channels, 50 cm drift, 50 cm diameter) has been operated in a 2T superconducting magnet at Saclay. A description of this apparatus and first results from cosmic ray tests are presented. Additional measurements using simpler detectors with a laser source, an X-ray gun and radio-active sources are discussed. Drift velocity and gain measurements, electron attachment and aging studies for a Micromegas TPC are presented. In particular, using simulations and measurements, it is shown that an $Argon-CF_4$ mixture is optimal for operatio…
The MEG-II experiment searches for the lepton flavor violating decay: mu in electron and gamma. The reconstruction of the positron trajectory uses a cylindrical drift chamber operated with a mixture of He and iC4H10 gas. It is important to provide a stable performance of the detector in terms of its electron transport parameters, avalanche multiplication, composition and purity of the gas mixture. In order to have a continuous monitoring of the quality of gas, we plan to install a small drift chamber, with a simple geometry that allows to measure very precisely the electron drift velocity in a…
Scintillation light produced in liquid xenon (LXe) by alpha particles, electrons and gamma-rays was detected with a large area avalanche photodiode (LAAPD) immersed in the liquid. The alpha scintillation yield was measured as a function of applied electric field. We estimate the quantum efficiency of the LAAPD to be 45%. The best energy resolution from the light measurement at zero electric field is 7.5%(sigma) for 976 keV internal conversion electrons from Bi-207 and 2.6%(sigma) for 5.5 MeV alpha particles from Am-241. The detector used for these measurements was also operated as a gridded io…
Wire chambers are routinely operated as tracking detectors in magnetic spectrometers at high-intensity continuous electron beams. Especially in experiments studying reactions with small cross-sections the reaction yield is limited by the background rate in the chambers. One way to determine the track of a charged particle through a multi-wire proportional chamber (MWPC) is the measurement of the charge distribution induced on its cathodes. In practical applications of this read-out method, the algorithm to relate the measured charge distribution to the avalanche position is an important factor…
Measurements of proton-nucleus scattering and high resolution neutrino-nucleus interaction imaging are key to reduce neutrino oscillation systematic uncertainties in future experiments. A High Pressure Time Projection Chamber (HPTPC) prototype has been constructed and operated at Royal Holloway University of London and CERN as a first step in the development of a HPTPC capable of performing these measurements as part of a future long-baseline neutrino oscillation experiment such as the Deep Underground Neutrino Experiment. In this paper we describe the design and operation of the prototype HPT…
Argon with an admixture of CF4 is expected to be a good candidate for the gas mixture to be used for a time projection chamber (TPC) in the future linear collider experiment because of its small transverse diffusion of drift electrons especially under a strong magnetic field. In order to confirm the superiority of this gas mixture over conventional TPC gases we carried out cosmic ray tests using a GEM-based TPC operated mostly in Ar-CF4-isobutane mixtures under 0 - 1 T axial magnetic fields. The measured gas properties such as gas gain and transverse diffusion constant as well as the observed …
Imaging techniques that use atmospheric muons, collectively named under the neologism "muography", have seen a tremendous growth in recent times, mainly due to their diverse range of applications. The most well-known ones include but are not limited to: volcanology, archaeology, civil engineering, nuclear reactor monitoring, nuclear waste characterization, underground mapping, etc. These methods are based on the attenuation or deviation of muons to image large and/or dense objects where conventional techniques cannot work or their use becomes challenging. In this context, we have constructed a…
The MuCap experiment at the Paul Scherrer Institute performed a high-precision measurement of the rate of the basic electroweak process of nuclear muon capture by the proton, $μ^- + p \rightarrow n + ν_μ$. The experimental approach was based on the use of a time projection chamber (TPC) that operated in pure hydrogen gas at a pressure of 10 bar and functioned as an active muon stopping target. The TPC detected the tracks of individual muon arrivals in three dimensions, while the trajectories of outgoing decay (Michel) electrons were measured by two surrounding wire chambers and a plastic scint…
We have directly measured the energy threshold and efficiency for bubble nucleation from iodine recoils in a CF3I bubble chamber in the energy range of interest for a dark matter search. These interactions cannot be probed by standard neutron calibration methods, so we develop a new technique by observing the elastic scattering of 12 GeV/c negative pions. The pions are tracked with a silicon pixel telescope and the reconstructed scattering angle provides a measure of the nuclear recoil kinetic energy. The bubble chamber was operated with a nominal threshold of (13.6+-0.6) keV. Interpretation o…
Due to their simplicity and comparatively low cost Resistive Plate Chambers are gaseous detectors widely used in high-energy and cosmic rays physics when large detection areas are needed. However, the best gaseous mixtures are currently based on tetrafluoroethane, which has the undesirable characteristic of a large Global Warming Potential (GWP) of about 1400 and because of this, it is currently being phased out from industrial use. As a possible replacement, tetrafluoropropene (which has a GWP close to 1) has been taken into account. Since tetrafluoropropene is more electronegative than tetra…
The Inner Tracker System of the HERA-B experiment at DESY consists of 184 Microstrip Gas Chambers (MSGC) with a total number of 147 456 electronic read out channels. The detectors have to cope with particle fluxes up to 25 kHz/mm**2 and to tolerate radiation doses of 1 Mrad per year. During the development of these chambers it was found that conventional MSGC, operated in intenses hadronic fluxes, are rapidly destroyed due to induced discharges. The introduction of a Gas Electron Multiplier (GEM) as pre-amplification structure offers the possibility to build robust and reliable detectors allow…
Due to their simplicity and comparatively low cost, Resistive Plate Chambers are gaseous detectors widely used in high-energy and cosmic rays physics, when large detection areas are needed. However, the best gaseous mixtures are currently based on tetrafluoroethane, which has the undesirable characteristic of a large Global Warming Potential (GWP) of about 1400 and, because of this, it is currently being phased out from industrial use. Tetrafluoropropene (which has a GWP close to 1) is being considered as a possible replacement. Since tetrafluoropropene is more electronegative than tetrafluoro…
The Multigap Resistive Plate Chamber (MRPC) is a gaseous detector; the performance depends very much on the gas mixture as well as the design. MRPCs are used as a timing device in several collider experiments and cosmic ray experiments thanks to the excellent timing performance. The typical gas mixtures of RPC-type detectors at current experiments are based on the gases $\rm C_2F_4H_2$ and $\rm SF_6$. These gases have very high Global Warming Potential (GWP) values of 1430 and 23900 respectively. The present contribution has been performed as a part of efforts to reduce the amount of greenhous…
A time projection chamber (TPC) with micropattern gaseous detector (MPGD) readout is investigated as main tracking device of the International Large Detector (ILD) concept at the planned International Linear Collider (ILC). A prototype TPC equipped with a triple gas electron multiplier (GEM) readout has been built and operated in an electron test beam. The TPC was placed in a 1 T solenoidal field at the DESY II Test Beam Facility, which provides an electron beam up to 6 GeV/c. The performance of the readout modules, in particular the spatial point resolution, is determined and compared to earl…
The DARWIN project aims to build and operate a next-generation observatory for dark matter and neutrino physics, featuring a time projection chamber with a proposed active target of 40 t of liquid xenon. As an R&D facility to test fundamental components of the future detector, Xenoscope, a full-scale vertical demonstrator with ~400 kg of liquid xenon and up to 2.6 m electron drift length, was built at the University of Zurich. Its main objective is to demonstrate electron drift over unprecedented distances in liquid xenon - first in a purity monitor setup with charge readout, followed by a dua…
Pressurized drift-tube chambers are efficient detectors for high-precision tracking over large areas. The Monitored Drift-Tube (MDT) chambers of the muon spectrometer of the ATLAS detector at the Large Hadron Collider (LHC) reach a spatial resolution of 35 micons and almost 100% tracking efficiency with 6 layers of 30 mm diameter drift tubes operated with Ar:CO2 (93:7) gas mixture at 3 bar and a gas gain of 20000. The ATLAS MDT chambers are designed to cope with background counting rates due to neutrons and gamma-rays of up to about 300 kHz per tube which will be exceeded for LHC luminosities …
