Rare-event search experiments located on-surface, such as short-baseline reactor neutrino experiments, are often limited by muon-induced background events. Highly efficient muon vetos are essential ...to reduce the detector background and to reach the sensitivity goals. We demonstrate the feasibility of deploying organic plastic scintillators at sub-Kelvin temperatures. For the NUCLEUS experiment, we developed a cryogenic muon veto equipped with wavelength shifting fibers and a silicon photo multiplier operating inside a dilution refrigerator. The achievable compactness of cryostat-internal integration is a key factor in keeping the muon rate to a minimum while maximizing coverage. The thermal and light output properties of a plastic scintillation detector were examined. We report first data on the thermal conductivity and heat capacity of the polystyrene-based scintillator UPS-923A over a wide range of temperatures extending below one Kelvin. The light output was measured down to 0.8 K and observed to increase by a factor of 1.61 ± 0.05 compared to 300 K. The development of an organic plastic scintillation muon veto operating in sub-Kelvin temperature environments opens new perspectives for rare-event searches with cryogenic detectors at sites lacking substantial overburden.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Performing X-ray polarimetry of astrophysical sources is a topic of growing interest, with only a few flying experiments dedicated to it so far. For soft X-rays sources detection from 1 keV to a few ...tens of keV, the best technique certainly consists in using the photoelectric effect, which is the dominant phenomenon at those energies in gaseous detectors. One of the main issues is the gaseous detector's reliability in space and the sensitivity to sparks of their associated front-end electronics caused by cosmic rays. To overcome this limitation, we investigate the opportunity of building a new spectro-polarimeter with outer and contactless radiation hard readout electronics, placed outside the gas chamber. In order to perform this, we use a Micromegas detector with a resistive anode spread on a ceramic plate. The signal is then transmitted by capacitive coupling to the outer electronics. The readout electronics in question, inherited from Caliste-HD, consists of a fine pitch 3D detector module developed at CEA initially designed for semi-conductor applications. In this paper we present the different parts of our experimental setup as well as recent results obtained by illuminating our prototype with an super(55)Fe source. In addition to the optimization of the detector's parameters, we also present the first spectrum of a soft X-ray gaseous detector with outer and contactless electronics and photo-electron tracks obtained with the detector making a step forward in the field of soft X-rays spectro-polarimeter.
A new segmented silicon-array called MUSETT has been built for the study of heavy elements using the Recoil-Decay-Tagging technique. MUSETT is located at the focal plane of the VAMOS spectrometer at ...GANIL and is used in conjunction with a γ-ray array at the target position. This paper describes the device, which consists of four 10×10cm2 Si detectors and its associated front-end electronics based on highly integrated ASICs electronics. The triggerless readout electronics, the data acquisition and the analysis tools developed for its characterization are presented. This device was commissioned at GANIL with the EXOGAM γ-ray spectrometer using the fusion–evaporation reaction 197Au(22Ne,5n)214Ac. Additionally, the performance of the VAMOS Wien filter used during the in-beam commissioning is also reported.
This paper describes a method based on photofission developed in our laboratory to characterize in depth large waste packages. The method consists in using photons of high-energy (Bremsstrahlung ...radiation) in order to induce reactions of photofission on the heavy nuclei present in the wastes. The measurement of the delayed neutrons allows quantifying the actinides in the wastes. We present the first results of measurement performed with a concrete mock-up of 870
l and two real waste packages.
Micromegas technology is a promising candidate to replace Atlas forward muon chambers -tracking and trigger- for future HL-LHC upgrade of the experiment. The LHC accelerator luminosity will be ten ...times the nominal one, increasing background and pile-up event probability in the same proportion. This requires detector performances which are currently under studies in intensive RD activities. We studied performances of four different resistive Micromegas detectors and with different read-out strip pitches. These chambers were tested using similar to 120GeV momentum pions with rates from 25 up to 250 kHz/cm super(2), at H6 CERN-SPS beam line in autumn 2010. We found that the resolution is degraded, if the strip pitch is too wide with respect to the charge distribution at the readout plane. To reduce the systematic effects of the charge sharing we propose a cluster reconstruction algorithm. For narrow strip pitch 500 mu m we measure a resolution of similar to 90 mu m and a efficiency of similar to 98%. The track angle effect on the efficiency was also studied. Our results show that resistive techniques induce no degradation on the efficiency or resolution, with respect to the standard Micromegas. In some configuration the resistive coating is able to reduce the discharge currents at least by a factor of 100 and no HV breakdown was observed.
Piggyback resistive Micromegas Attié, D; Chaus, A; Durand, D ...
Journal of instrumentation,
11/2013, Letnik:
8, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Piggyback Micromegas is a novel readout architecture where the anode element is made of a resistive layer on a ceramic substrate. The resistive layer is deposited on the thin ceramic substrate by an ...industrial process which provides a large dynamic range of resistivity (10 super(6) to 10 super(10) MOmega/whitesquare). The particularity of this new structure is that the active part is entirely dissociated from the read-out element. This gives a large flexibility on the design of the anode structure and the readout scheme. Without significant loss, signals are transmitted by capacitive coupling to the read-out pads. The detector provides high gas gain, good energy resolution and the resistive layer assures spark protection for the electronics. This assembly could be combined with modern pixel array electronic ASICs. First tests with different Piggyback detectors and configurations will be presented. This structure is adequate for cost effective fabrication and low out gazing detector. It was designed to perform in sealed mode and its long term stability has been extensively studied. In addition perspectives on the future developments will be evoked.
Resistive-anode micromegas detectors have been in development for several years, in an effort to solve the problem of sparks when working at high flux and high ionizing radiation like in the HL-LHC ...(up to ten times the luminosity of the LHC). They have been chosen as one of the technologies that will be used in the ATLAS New Small Wheel project (forward muon system). An ageing study is mandatory to assess their capabilities to handle the HL-LHC environment on a long-term period. A prototype has been exposed to several types of irradiation (X-rays, cold neutrons, super(60)Co gammas and alphas) above the equivalent charge produced in the detector in five HL-LHC running years without showing any degradation of the performance in terms of gain and energy resolution, and with the characterization of the tracking performance in terms of efficiency and spatial resolution, verifying non degradation on the exposed resistive micromegas.
The micromegas technology is a promising candidate to replace the forward muon chambers for the luminosity upgrade of ATLAS. The LHC accelerator luminosity will be five times the nominal one, ...increasing background and pile-up event probability. This requires detector performances which are currently under study in intensive R&D activities. Aging is one of the key issues for a high-luminosity LHC application. For this reason, we study the properties of resistive micromegas detectors under intense X-ray radiation and under thermal neutrons in different CEA-Saclay facilities. This study is complementary to those already performed using fast neutrons.
New developments of Micromegas detector Delbart, A.; Oliveira, R.De; Derré, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2001, Letnik:
461, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A new type of micromesh, based on etching techniques, has been developed for the Micromegas detector. In this paper, we will briefly describe this new design and give some results about the ...performances obtained in different gas mixtures. The geometry of the mesh allows good uniformity of the electrostatic field. An energy resolution of 11.7
% full-width at half-maximum is obtained with X-rays at 5.9
keV and 5.4
% at 22
keV in an argon/isobutane (90%/10%) gas mixture. This is a significant improvement for a gaseous detector operating at high gain (about 5000).
Experimental studies of a Micromegas neutron detector Andriamonje, S; Cano-Ott, D; Delbart, A ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2002, Letnik:
481, Številka:
1
Journal Article
Recenzirano
A Micromegas detector to be used as a neutron beam profiler has been tested in the CENBG neutron beam. Two thin solid targets (
6
Li and
10
B) have been used as neutron converters. We report results ...on the detection efficiency and spatial resolution of the detector.
PDF
