Development of a fast gaseous detector: ‘Micromegas’ Barouch, G; Bay, A; Bouchigny, S ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/1999, Letnik:
423, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Several
15×15
cm
2
gaseous Micromegas chambers (MICROMEsh GAseous Structure) which consist of a conversion gap and an amplification gap separated by a thin grid have been extensively tested in ...low-intensity
10
GeV/c
pion beam and high-intensity (up to
5×10
5
Hz/
mm
2)
100
GeV/c
muon beam. The detector behaviour has been studied with respect to many parameters: conversion gaps of 1 and 3
mm, amplification gaps of 50 and 10
μm, an external magnetic field and many different filling gases. So far no effect of the magnetic field up to 1.3
T has been observed. The gas mixture argon + cyclohexane appears to be very suitable with gains above 10
5 and a full-efficiency plateau of 50
V at 340
V. With a conversion gap as small as 1
mm and an electronics with a threshold at 5000 electrons the efficiency reaches 96%. With the addition of CF
4 a time resolution of 5
ns (RMS) has been obtained. A spatial resolution better than
60
μ
m has been observed with anode strips of
317
μ
m pitch and was explained by transverse diffusion in the gas. Simulations show that with a pitch of
100
μ
m and the appropriate gas a resolution of
10
μ
m is within reach. This development leads to a new generation of cheap position-sensitive detectors which would permit high-precision tracking or vertexing close to the interaction region, in very high-rate environments.
We present particle beam test results using a high-rate, high-position and high-time-resolution gaseous detector, ‘Micromegas’, of
15×15
cm
2
. The rate capability was measured with 10
MeV protons ...from a TANDEM accelerator. No effect on gain was observed at particle rates up to
10
9
mm
−2
s
−1. With an argon and DME filling the gain was stable up to 50 mC total charge on a
3
mm
2
area. With minimum-ionizing particles in a CERN beam a high efficiency, close to 100%, was measured, under stable conditions. A first space-resolution measurement of
50
μ
m
±20
μ
m was obtained. The operation of the chamber shows that it is possible to optimize the geometrical parameters in order to improve the space resolution and bring the time resolution low enough to contain the events of each beam crossing (every 25
ns) in the European Large Hadron Collider. Further work in this direction is being actively pursued.
In this report, we present results of gain studies using various gas mixtures in a novel structure of a gaseous detector called MICROMEGAS which is under development at Saclay. We in particular ...studied the maximum of gain achievable with MICROMEGAS before the discharge. We tried various gas mixtures (argon, neon, CF/sub 4/) with various proportions of quencher (isobutane, cyclohexane, DME). We also studied the radiation hardness of MICROMEGAS using argon-isobutane and CF/sub 4/-isobutane mixtures.
MICROMEGAS: high rate and radiation hardness results Puill, G.; Derre, J.; Giomataris, Y. ...
1998 IEEE Nuclear Science Symposium Conference Record. 1998 IEEE Nuclear Science Symposium and Medical Imaging Conference (Cat. No.98CH36255),
1998, Letnik:
1
Conference Proceeding
In this report, we present results of gain studies using various gas mixtures in a novel structure of gaseous detector called MICROMEGAS which is under development at Saclay. We in particular studied ...the maximum of gain achievable with MICROMEGAS before the discharge. We tried various gas mixtures (argon, neon, CF/sub 4/) with various proportions of quencher (isobutane, cyclohexane, DME). We also studied the radiation hardness of MICROMEGAS using argon-isobutane and CF/sub 4/-isobutane mixtures.
The UA9 Experiment at CERN-SPS investigates channeling processes in bent silicon crystals with the aim to manipulate hadron beams. Monitoring and characterization of channeled beams in the high ...energy accelerators environment ideally requires in-vacuum and radiation hard detectors. For this purpose the Cherenkov detector for proton Flux Measurement (CpFM) was designed and developed. It is based on thin fused silica bars in the beam pipe vacuum which intercept charged particles and generate Cherenkov light. The first version of the CpFM is installed since 2015 in the crystal-assisted collimation setup of the UA9 experiment.
In this paper the procedures to make the detector operational and fully integrated in the UA9 setup are described. The most important standard operations of the detector are presented. They have been used to commission and characterize the detector, providing moreover the measurement of the integrated channeled beam profile and several functionality tests as the determination of the crystal bending angle. The calibration has been performed with Lead (Pb) and Xenon (Xe) beams and the results are applied to the flux measurement discussed here in detail.
NDIP20: 9th International Conference on New Developments in Photodetection Bougamont, E.; Carrel, F.; Chipaux, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
June 2023, 2023-Jun, 2023-06-00, 20230601, Letnik:
1051
Journal Article
Study of the doubly charmed tetraquark Tcc Abdelmotteleb, A. S. W; Ajaltouni, Z; Andreianov, A ...
Nature communications,
12/2022, Letnik:
13, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and ...mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar Tcc+ tetraquark with a quark content of ccu¯d¯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector Tcc+ state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the Tcc+ state. In addition, an unexpected dependence of the production rate on track multiplicity is observed.The existence and properties of tetraquark states with two heavy quarks and two light antiquarks have been widely debated. Here, the authors use a unitarized model to study the properties of an exotic narrow state compatible with a doubly charmed tetraquark.
The first simultaneous test of muon-electron universality using B+→K+ℓ+ℓ− and B0→K*0ℓ+ℓ− decays is performed, in two ranges of the dilepton invariant-mass squared, q2. The analysis uses beauty mesons ...produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb−1. Each of the four lepton universality measurements reported is either the first in the given q2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.
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