New Experiments With Spheres-Gas (NEWS-G) is a direct dark matter detection experiment using Spherical Proportional Counters (SPCs) with light noble gases to search for low-mass Weakly Interacting ...Massive Particles (WIMPs). We report the results from the first physics run taken at the Laboratoire Souterrain de Modane (LSM) with SEDINE, a 60 cm diameter prototype SPC operated with a mixture of Ne + CH4 (0.7%) at 3.1 bars for a total exposure of 9.6 kg · days. New constraints are set on the spin-independent WIMP-nucleon scattering cross-section in the sub-GeV/c2 mass region. We exclude cross-sections above 4.4×10−37cm2 at 90% confidence level (C.L.) for a 0.5 GeV/c2 WIMP. The competitive results obtained with SEDINE are promising for the next phase of the NEWS-G experiment: a 140 cm diameter SPC to be installed at SNOLAB by summer 2018.
Recent developments have shown that coupling a Micromegas gaseous detector on a glass substrate with a transparent anode and a CMOS camera enables the optical readout of Micromegas detectors with a ...good spatial resolution, demonstrating that the glass Micromegas detector is well-suited for imaging. This feasibility test has been effectuated with low-energy X-ray photons also permitting energy resolved imaging. This test opens the way to different applications. Here we will focus on two applications. Namely, neutron imaging for non-destructive examination of highly gamma-ray emitting objects, such as irradiated nuclear fuel or radioactive waste. And secondly, we are developing a beta imager for the cell tagging in the field of anticancerous drug studies.
Both applications require to design the detectors in view of the specific constraints of reactor dismantling and medical applications: spatial resolution and strong gamma suppression for neutron imaging and precise rate and energy spectrum measurements for the beta.
A dedicated system consisting of a glass Micromegas detector and an ultrasensitive camera has been designed and assembled. Here we present the first results from the characterization of the detectors, as well as the first acquired images.
Radiation imaging with glass Micromegas Brunbauer, F.M.; Desforge, D.; Ferrer-Ribas, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2020, Letnik:
955
Journal Article
Recenzirano
Odprti dostop
Optically recording scintillation light emitted by MicroPattern Gaseous Detectors (MPGDs) with imaging sensors is a versatile and performant readout modality taking advantage of modern high ...granularity imaging sensors. To allow scintillation light readout of a detector based on MicroMesh Gaseous Structure (Micromegas) technology, we have integrated a Micromegas on a glass substrate with a transparent anode. In addition to optical detection of scintillation light emitted during electron avalanche multiplication between the micromesh and the anode, this setup also achieves a good energy resolution. A glass Micromegas detector was operated in an Ar/CF4 gas mixture and showed a response comparable to conventional Micromegas detectors. The spectrum of the emitted scintillation light was recorded and shown to be equivalent to the one obtained with other gaseous detectors in the same gas mixture. Optically read out images were recorded with CCD cameras and integrated X-ray radiographic imaging with good spatial resolution was demonstrated. A spatial resolution of 440μm (10% MTF) was found. Single X-ray photon detection with a high-sensitivity camera was achieved, which potentially permits energy-resolved X-ray fluorescence imaging.
Timing performance of a Micro-Channel-Plate Photomultiplier Tube Bortfeldt, J.; Brunbauer, F.; David, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
960, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The spatial dependence of the timing performance of the R3809U-50 Micro-Channel-Plate PMT (MCP-PMT) by Hamamatsu was studied in high energy muon beams. Particle position information is provided by a ...GEM tracker telescope, while timing is measured relative to a second MCP-PMT, identical in construction. In the inner part of the circular active area (radius r<5.5 mm) the time resolution of the two MCP-PMTs combined is better than 10 ps. The signal amplitude decreases in the outer region due to less light reaching the photocathode, resulting in a worse time resolution. The observed radial dependence is in quantitative agreement with a dedicated simulation. With this characterization, the suitability of MCP-PMTs as t0 reference detectors has been validated.
Precise in-situ measurements of the neutron flux in underground laboratories is crucial for direct dark matter searches, as neutron induced backgrounds can mimic the typical dark matter signal. The ...development of a novel neutron spectroscopy technique using Spherical Proportional Counters is investigated. The detector is operated with nitrogen and is sensitive to both fast and thermal neutrons through the 14N(n, α)11B and 14N(n, p)14C reactions. This method holds potential to be a safe, inexpensive, effective, and reliable alternative to 3He-based detectors. Measurements of fast and thermal neutrons from an Am-Be source with a Spherical Proportional Counter operated at pressures up to 2 bar at Birmingham are discussed.
Precise in-situ measurements of the neutron flux in underground laboratories is crucial for direct dark matter searches, as neutron induced backgrounds can mimic the typical dark matter signal. The ...development of a novel neutron spectroscopy technique using Spherical Proportional Counters is investigated. The detector is operated with nitrogen and is sensitive to both fast and thermal neutrons through the
14
N(n,
α
)
11
B and
14
N(n, p)
14
C reactions. This method holds potential to be a safe, inexpensive, effective, and reliable alternative to
3
He-based detectors. Measurements of fast and thermal neutrons from an Am-Be source with a Spherical Proportional Counter operated at pressures up to 2 bar at Birmingham are discussed.
Timing performance of a multi-pad PICOSEC-Micromegas detector prototype Aune, S.; Bortfeldt, J.; Brunbauer, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2021, Letnik:
993, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The multi-pad PICOSEC-Micromegas is an improved detector prototype with a segmented anode, consisting of 19 hexagonal pads. Detailed studies are performed with data collected in a muon beam over four ...representative pads. We demonstrate that such a device, scalable to a larger area, provides excellent time resolution and detection efficiency. As expected from earlier single-cell device studies, we measure a time resolution of approximately 25 picoseconds for charged particles hitting near the anode pad centres, and up to 30 picoseconds at the pad edges. Here, we study in detail the effect of drift gap thickness non-uniformity on the timing performance and evaluate impact position based corrections to obtain a uniform timing response over the full detector coverage.
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