Proportional Wire Chambers Research Articles

Commissioning of a hybrid readout TPC test set-up and gas gain simulations

A hybrid readout Time Projection Chamber (TPC) has a simultaneous optical- and charge readout. The optical readout provides 2D images of particle tracks in the active volume, whilst the charge readout provides additional information on the particle position perpendicular to the image plane. A hybrid readout TPC working at high pressure is an attractive device for physics cases where an excellent space point resolution and a high target density is required as e.g. measuring a neutrino beam at the source of a long baseline neutrino oscillation experiment. In this paper we present two different lines of work towards the goal of developing hybrid TPC technology: a) Commissioning of a set-up with gas electron multipliers employing optical and charge readout. b) An analytical parametrisation of the gas gain for a multi wire proportional chamber based on GARFIELD++ simulations, which – when validated with measurements – allows to skip these simulations in the future altogether.

Comparative aging studies on a single wire proportional chamber

In order to extend previous studies and test additional variables playing a role in the aging processes, a single wire proportional chamber was specially designed. In this contribution, the author will present the result of two types of tests performed on this single wire proportional chamber. During the first test, the single wire proportional chamber was irradiated with X-rays and alpha particles with the same hit rate until the same collected charge (1.4 mC/cm) was reached. Nevertheless the performance loss during the x-ray irradiation was larger, traces of polymers were found on the wire only in the case of alpha irradiation. The second test was performed irradiating the single wire proportional chamber with alphas and X-rays, but this time with the same anodic current i.e. very different hit rate. The irradiation continued until the wire chamber lost about half of the initial gas gain. In the case of alpha irradiation the integrated charge needed for the goal was lower with respect to the one needed during the x-ray radiation: 9.5 and 33.0 mC/cm, respectively. However, the electron microscope analysis revealed, once again, a large polymer deposit on the alpha irradiated wire while no deposit was found on the X-ray irradiated one.

Proposal on application of the multi-wire proportional chambers of the LHCb MUON Detector at very high rates for the future upgrades

The MUON Detector (MD) of LHCb is one of the largest instruments of this kind worldwide, and one of the most irradiated. It has performed exceptionally well during the RUN1 and RUN2 of the LHC at an instantaneous luminosity of 4×1032 cm−2s−1, with tracking inefficiencies at the level of 1% and 2.6%, respectively. Looking forward for the future LHCb Upgrade 2 (U2) planned in 2031 and aiming in running the detector at increased luminosity by factor 0∼5, and at the same time keeping a very high (∼99%) detection efficiency, an option with reuse significant part of the present Multi Wire Proportional Chambers (MWPC) in a new Muon System is presented. In addition, the first idea of new Front End Electronics (FEE) and an existing test setup applicable for designing both: new MWPCs with higher granularity of the cathode readout pads and new FEE are described.

PID performance of the High Momentum Particle IDentification (HMPID) detector during LHC-Run 2

Abstract The ALICE apparatus is devoted collecting proton–proton (pp), proton–nucleus (p–A) and nucleus–nucleus (A–A) collision data provided by the LHC, to study the properties of strongly interacting matter under extremely high temperature and energy density conditions. In ALICE, the momentum of a track is evaluated by exploiting a solenoid magnetic field of 0.5 T. Among the ALICE PID detectors, the HMPID (High Momentum Particle Identification Detector) is devoted to the identification of charged hadrons . It consists of seven identical RICH (Ring Imaging Cherenkov) counters, with liquid C 6 F14 as Cherenkov radiator (n ≈ 1.298 at λ ph = 175 nm). Cherenkov photons and charged particles are detected by a MWPC (Multi Wire Proportional Chamber), equipped with a pad-segmented CsI coated photo-cathode. The HMPID provides 3 σ K– π and p–K separation up to p T = 3 and 5 GeV/ c , respectively. The detector performance depends on the experimental conditions, such as the event multiplicity and the intensity of the solenoid magnetic field. During the LHC Run 2 data-taking period (2015–2017), the HMPID collected data from different colliding systems with a magnetic field intensity B = 0.5 T and pp data with B = 0.2 T were also recorded. A review of the detector PID performance during the LHC Run 2 data-taking period will be shown. The contribution provided, so far, by the HMPID to the ALICE physics measurements, performed with the LHC Run 2 data, will also be presented.

Active Oxygen Target for Studies in Nuclear Astrophysics with Laser Compton Backscattered γ-ray Beams

An active target is being developed to be used in low-energy nuclear astrophysics experiments. It is a position- and time-sensitive detector system based on the low-pressure Multi Wire Proportional Chamber (MWPC) technique. Methylal ((OCH3)2CH2), at a pressure of a few Torr, serves as the working gas for MWPC operation, and in addition, the oxygen atoms of the methylal molecules serve as an experimental target. The main advantage of this new target detector system is that it has high sensitivity to the low-energy, highly-ionizing particles produced after photodisintegration of 16O and insensitivity to γ-rays and minimum ionizing particles. This allows users to detect only the products of the nuclear reaction of interest. The threshold energies for detection of α particles and 12C nuclei are about 50 keV and 100 keV, respectively. The main disadvantage of this detector is the small target thickness, which is around a few tens of μg/cm2. However, reasonable luminosity can be achieved by using a multimodule detector system and an intense, Laser Compton Backscattered (LCB) γ-ray beam. This paper summarizes the architecture of the active target and reports test results of the prototype detector. The tests investigated the timing and position resolutions of 30 × 30 mm2 low-pressure MWPC units using an α-particle source. The possibility of measuring the 16O(γ, α)12C cross-section in the 8–10 MeV energy region by using a LCB γ-ray beam is also discussed. A measurement of the 16O(γ, α)12C cross-section will enable the reaction rate of 12C(α, γ)16O to be determined with significantly improved precision compared to previous experiments.

Construction of Multi Wire Proportional Chambers for the CBM Transition Radiation Detector

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) will explore the QCD phase diagram in the region of high net-baryon densities. The Transition Radiation Detector (TRD) with its multi-layer design will provide electron identification for higher momenta and contribute to the fragment identification.

The Use of 3D Printing in the Development of Gaseous Radiation Detectors

Fused Deposition Modelling has been used to produce a small, single wire, Iarocci-style drift tube to demonstrate the feasibility of using the Additive Manufacturing technique to produce cheap detectors, quickly. Recent technological developments have extended the scope of Additive Manufacturing, or 3D printing, to the possibility of fabricating Gaseous Radiation Detectors, such as Single Wire Proportional Counters and Time Projection Chambers. 3D printing could allow for the production of customisable, modular detectors; that can be easily created and replaced and the possibility of printing detectors on-site in remote locations and even for outreach within schools. The 3D printed drift tube was printed using Polylactic acid to produce a gas volume in the shape of an inverted triangular prism; base length of 28 mm, height 24.25 mm and tube length 145 mm. A stainless steel anode wire was placed in the centre of the tube, mid-print. P5 gas (95% Argon, 5% Methane) was used as the drift gas and a circuit was built to capacitively decouple signals from the high voltage. The signal rate and average pulse height of cosmic ray muons were measured over a range of bias voltages to characterise and prove correct operation of the printed detector.

Discharge and stability studies for the new readout chambers of the upgraded ALICE TPC

The ALICE (A Large Ion Collider Experiment) Time Projection Chamber (TPC) at CERN LHC is presently equipped with Multi Wire Proportional Chambers (MWPCs). A gating grid prevents ions produced during the gas amplification from moving into the drift volume. The maximum drift time of the electrons together with the closure time of the gating grid allows a maximum readout rate of about 3 kHz. After the Long Shutdown 2 (from 2021 onwards), the LHC will provide lead-lead collisions at an expected interaction rate of 50 kHz. To take data at this rate the TPC will be upgraded with new readout chambers, allowing for continuous read-out and preserving the energy and momentum resolution of the current MWPCs. Chambers with a stack of four Gas Electron Multipliers (GEMs) fulfil all the performance requirements, if the voltages applied to the GEMs are tuned properly. In order to ensure that these chambers are stable while being operated at the LHC, studies of the discharge behaviour were performed. We report on studies done with small prototypes equipped with one or two GEMs. Discharges were voluntarily induced by a combination of high-voltages across the GEM(s) and highly ionising particles. During these studies, the phenomenon of ``secondary discharges'' has been observed. These occur only after an initial discharge when the electric field above or below the GEM is high enough. The time between the initial and the secondary discharge ranges from several 10 μs to less than 1 μs, decreasing with increasing field. Using decoupling resistors in the high-voltage supply path of the bottom side of the GEM shifts the occurrence of these discharges to higher electric fields.

The calibration of elastic scattering angular distribution at low energies on HIRFL-RIBLL

The precise calibration of angular distribution of heavy-ion elastic scattering induced by Radioactive Ion Beams (RIBs) at energies around Coulomb barrier on the Radioactive Ion Beam Line in Lanzhou (RIBLL) at the Heavy-Ion Research Facility in Lanzhou (HIRFL) is presented. The beam profile and the scattering angles on the target are deduced by a measurement with two Multi Wire Proportional Chambers (MWPC), and four sets of detector telescopes (including Double-sided Silicon Strip Detectors (DSSD) placed systematically along the beam line, incorporating with Monte Carlo simulation. The MWPCs were used to determine the beam trajectory before the target, and the energies and the positions of scattered particles on the detectors were measured by the DSSDs. Minor corrections on the beam spot and the detector position are performed by assuming the pure Rutherford scattering at angles which are smaller than the related grazing angle. This method is applied for the elastic scattering of 17F on 89Y target at Elab=59MeV and 50MeV.

Detector system for the angular distribution measurement of 12C + 12C elastic scattering at 200–400A MeV

To obtain the angular distributions of 12C + 12C elastic scatterings with the incident energies of 200–400AMeV for the study of three-body forces, a detector system was constructed at second Radioactive Ion Beam Line in Lanzhou (RIBLL2) of Institute of Modern Physics (IMP). This system was composed of five plastic scintillation detectors with two read-outs for each detector, a Multi Wire Proportional Chamber (MWPC) and a 4×4 CsI(Tl) array. The 12C beam with the incident energy of 200AMeV on a natural carbon target was used to test this detector system. It is found that the plastic scintillation detector can give the good energy loss (ΔE) and time of flight (TOF) signals, it can also reflect the position information of scattered 12C events. MWPC can precisely provide the trajectories of scattered particles. This system has a very good particle identification ability and can clearly distinguish the scattered 12C particles from the fragments. It can be used for the study of the three-body forces effect for high energy heavy-ion scattering.

Building a large-area GEM-based readout chamber for the upgrade of the ALICE TPC

A large Time Projection Chamber (TPC) is the main device for tracking and charged-particle identification in the ALICE experiment at the CERN LHC. After the second long shutdown in 2019–2020, the LHC will deliver Pb beams colliding at an interaction rate up to 50kHz, which is about a factor of 100 above the present read-out rate of the TPC. To fully exploit the LHC potential the TPC will be upgraded based on the Gas Electron Multiplier (GEM) technology.A prototype of an ALICE TPC Outer Read-Out Chamber (OROC) was equipped with twelve large-size GEM foils as amplification stage to demonstrate the feasibility of replacing the current Multi Wire Proportional Chambers with the new technology. With a total area of ∼0.76m2 it is the largest GEM-based detector built to date. The GEM OROC was installed within a test field cage and commissioned with radioactive sources.

Performance simulation studies for the ALICE TPC GEM upgrade

To be able to exploit the anticipated interaction rate of 50kHz in Pb–Pb collisions during run 3 of the LHC (beyond 2019), the ALICE TPC will be upgraded to allow continuous readout. As this is not possible with the current Multi Wire Proportional Chamber (MWPC) based amplification, the readout will be replaced with Gas Electron Multiplier (GEM) readout chambers that can suppress ~99% of the ion back flow. The space charge of the remaining 1% ion back flow, however, will cause significant distortions to the measured tracks of order cm. Simulation studies to characterize the distortions and test correction strategies have been performed, which show that the intrinsic momentum resolution, without these distortions, can be recovered.

Upgrades of the ALICE TPC Front-End Electronics for Long Shutdown 1 and 2

This paper presents the front-end electronics upgrades of the ALICE Time Projection Chamber detector for the coming years, with a focus on the upgrades for Long Shutdown 2. The Large Hadron Collider is currently in Long Shutdown 1 following a successful first run, and upgrades of the detectors are underway to support the higher particle interaction rates planned for the next run. For the Time Projection Chamber, the increase in data due to the higher interaction rate and higher energy will cause a bottleneck in the Readout Control Unit and a new board is in development which increases the data-link speed to the back-end. Another more general upgrade of the ALICE experiment is planned for Long Shutdown 2, foreseen to start in 2018. In this case the goal is to cope with an even higher interaction rate of 50 kHz for Pb–Pb collisions. The present Multi Wire Proportional Chambers of the Time Projection Chamber will then be replaced by Gas Electron Multiplier technology. At the same time, the front-end electronics and readout system will also be replaced.

DeeMe experiment – An experimental search for a mu-e conversion reaction at J-PARC MLF

A new experiment searching for a mu-e conversion in nuclear field is going to be conducted at J-PARC Material Life Science Facility. Expected single event sensitivity of the experiment is 2×10−14 with 1MW accelerator operation and 2×107s data taking. Electron spectrometer is planned to be composed of low mass thin gap multi wire proportional chambers and research and development works with the prototype detector is performed.

A Large GEM-TPC Prototype Detector for anda

The PANDA spectrometer will be a state of the art universal detector for strong interaction studies at the High-Energy Storage Ring (HESR) in the future international Facility for Anti-proton and Ion Research (FAIR) at GSI, Darmstadt. The detector is designed to take advantage of the extraordinary physics potential which will be available utilizing high intensity, phase space cooled anti-proton beams. This facility will provide a cooled anti-proton beam −2 with momenta of 1.5-15 GeV/c, a maximal luminosity of 2×10 32 cms −1 that translates into 2×10 7 pp annihilations per second. A GEM based Time Projection Chamber (TPC) was one of the central tracker candidates for the PANDA experiment. To check the feasibility of such a detector system, a large prototype GEM-TPC was built and tested inside the FOPI Spectrometer at GSI. A set of three Gas Electron Multiplier (GEM) foils were used as amplification stage instead of Multi Wire Proportional Chambers. In this report, the design, construction, characterization of the prototype-detector system will be discussed in detail along with the results of recent beam tests.

Study of the Influence of Construction Materials on the Ageing Properties of High Rate Gas Detectors

Abstract An infrastructure has been set up at the GSI detector laboratory to study the influence of construction materials on the ageing properties of gas filled detectors such as multi wire proportional chambers (MWPC), gas electron multipliers (GEM) etc. As a first step an ageing test of silicone-based glue (RTV-3145)(Dow Corning) has been performed. In this article details of the experimental set-up and the first result on (RTV3145) will be presented.

Periodic Variations in Muon Flux at Project GRAND

GRAND consists of 64 proportional wire chamber detector stations located near the University of Notre Dame and has been used to detect muons since 1995. In this study, 117 days of data has been analyzed to investigate the dynamics of the daily mean variation in cosmic ray flux over the course of a season. This study used GRAND single track muon flux data from 21 July 2007 to 8 January 2008 which were corrected for both temperature and pressure. Fourier transforms and other techniques were used to identify periodic trends in the data sets. Also a sliding FFT was used to investigate the changes of those trends over the course of the collection period. The power spectra revealed significant one and two cycle per day variations which also changed in relative amplitude and phase signifi- cantly over this period. This analysis reveals significant seasonal trends in muon flux.

Signal shapes in a TPC wire chamber

We study signal shapes in Multi Wire Proportional Chambers (MWPCs) and the influence of the electron distribution around the wire on the ion tail characteristics. Simulations of the ion tail for two different geometries, different voltages and therefore gas gains were performed. These simulations are compared to measurements carried out with the ALICE TPC wire chambers for a Ne/CO 2/N 2 gas mixture, which allows to extract the avalanche spread around the anode wires of the MWPC.

Experimental data and analysis of the October 2003 Forbush decrease

On October 28, 2003 an Earthward-directed coronal mass ejection (CME) was observed from SOHO/LASCO imagery in conjunction with an X17 solar flare. The CME, traveling at nearly 2000 km/s, impacted the Earth on October 29, 2003 causing ground-based particle detectors to register a counting rate drop known as a Forbush decrease. The CME was not only responsible for affecting the rate of cosmic rays, but also caused anisotropies in their direction of incidence. Data from Project GRAND, an array of proportional wire chambers which detects secondary muons, are presented during the time of this Forbush decrease.

Test Suite for the LHCb Muon Chambers Quality Control

This paper describes the apparatus and the procedures implemented to test the front-end (FE) electronics of the LHCb muon detector multi wire proportional chambers (MWPC). Aim of the test procedure is to diagnose every FE channel of a given chamber by performing an analysis of the noise rate versus threshold and of the performances at the operational thresholds. Measurements of the key noise parameters, obtained while performing quality tests on the MWPC chambers before the installation on the experiment, are presented. The test suite proved to be an automatic, fast and user-friendly system for mass production tests of chambers. It provided the electronic identification of every chamber and FE board, and the storage and bookkeeping of test results that will be made available to the experiment control system during data taking.