The propagation velocity of scintillation light in liquid argon vg at λ∼128 nm wavelength, has been measured for the first time in a dedicated experimental setup at CERN. The obtained result ...1/vg=7.46±0.08 ns/m, is then used to derive the value of the refractive index (n) and the Rayleigh scattering length (L) for liquid argon in the VUV region. For λ=128 nm we found n=1.358±0.003 and L=99.1±2.3 cm. The measured values are of interest for a variety of experiments searching for rare events like neutrino and dark matter interactions. The derived quantities also represent key information for theoretical models describing the propagation of scintillation light in liquid argon.
The ICARUS-T600 Liquid Argon (LAr) Time Projection Chamber (TPC) is taking data with the Fermilab Booster Neutrino Beam-line (BNB) in the Short Baseline Neutrino (SBN) program to search for a ...possible LSND-like sterile neutrino signal. A light detection system, based on 360 Hamamatsu R5912-MOD Photo-Multiplier Tubes (PMTs) deployed behind the TPC wire chambers, has been realized to detect vacuum ultraviolet (VUV) photons produced by ionizing particles in LAr. This system is fundamental for the detector operation, providing an efficient trigger and contributing to the 3D reconstruction of events. Moreover, since the TPC is exposed to a huge flux of cosmic rays due to its shallow depths operations, the light detection system allows for the time reconstruction of events, contributing to the identification and to the selection of neutrino interactions within the beam spill gates.
Properties of the propagation of scintillation light in liquid argon (LAr), at λ∼128 nm wavelength, have been experimentally investigated in a dedicated setup at CERN. The speed of scintillation ...photons has been measured for the first time in this medium, refractive index and the Rayleigh scattering are being studied as well. Such measurement provides a key ingredient for the interpretation of data from the current and next generation large mass LAr detectors as those dedicated to the search for rare events such as neutrinos or Dark Matter. Furthermore the improvement on the understanding of the scintillation light propagation represent a benchmark for the multiple theoretical models and simulations for the next generation of detectors which are now based on still incomplete measurements and calculations.
•Measurement of the scintillation light propagation speed in liquid argon.•Optical properties as refractive index and Rayleigh Scattering (λ=128 nm) are derived.•Measurement of interest for LAr-based large scale future experimental setups.•Results can be used to improve current Monte Carlo simulations.
A particle detector that exploits Liquid Argon scintillation light Babicz, M.; Diwan, M.; Fava, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
Recenzirano
A number of innovative experiments dedicated to neutrino oscillations and rare event physics, such as direct searches for dark matter particles or neutrinoless double beta decays, are using liquefied ...noble-gases, particularly Liquid Argon (LAr), as detection media. Among many advantages of noble liquids, from the detection point of view, the most important ones are high scintillation and ionisation yields, possible long drift paths of ionisation electrons and feasible large detector masses. LAr is sufficiently dense and relatively cheap and therefore is the only adequate noble liquid for huge volumes.
This paper describes a particle detection system that exploits the prompt signals from the scintillation light produced by ionising particles in LAr. The detector has been exposed to cosmic rays. The system performance in terms of trigger efficiency and timing resolution, with a view to its application in neutrino detectors, is presented.
•Particle detection system that exploits the LAr scintillation light has been set up.•The system enables studies of PMTs, DAQ and trigger electronic performances.•The study involves temperature stability, electronic noise and timing synchronisation.•The tests within this system are an important input for a future large LAr detector.
Abstract
The ICARUS-T600 Liquid Argon (LAr) Time Projection Chamber (TPC) is presently taking data
in the Short Baseline Neutrino (SBN) program at Fermilab (U.S.A.) to search for a possible LSND-like
...sterile neutrino signal at Δ
m
2
≈ 1 eV
2
with the Booster Neutrino Beam (BNB). A
light detection system, based on 360 large area Photo-Multiplier Tubes (PMTs), has been realized
for ICARUS-T600 to detect VUV photons produced by the passage of ionizing particles in LAr. This
system is fundamental for the TPC operation, providing an efficient trigger and contributing to
the 3D reconstruction of events. Moreover, since the detector is exposed to a huge flux of cosmic
rays due to its shallow depths installation, the light detection system allows for the time
reconstruction of events, contributing to the identification and to the selection of genuine
neutrino interactions. The correct time reconstruction of events requires the precise knowledge of
the delay of each PMT channel and a good synchronization of recording electronics, this last based
on fast sampling digitizers. To achieve a time resolution better than 1 ns, we perform three
consecutive timing corrections deployed at different stages of the optical data flow. Results
demonstrate the capability of the ICARUS-T600 light detection system to allow a precise
reconstruction of the temporal evolution of each event occurring in the detector and the
association of neutrino events with the bunched structure of BNB.
Abstract This work presents an experimental setup designed for measuring optical properties in the vacuum ultraviolet (VUV) region. Originally developed for the characterization of ICARUS ...photomultiplier tubes, the setup has been recently employed to measure the conversion efficiency of para-Terphenyl coatings, acting as wavelength shifters, as a function of thickness. The VUV region is of particular interest in particle physics experiments utilizing cryogenic noble gases as scintillating media. The setup includes a deuterium light source, a mirror system, an intensity monitor, and a sample chamber to host sample and photodetector. An example measurement of para-Terphenyl conversion efficiency — as wavelength shifter — with varying thickness is presented, demonstrating the versatility and effectiveness of the presented system.
The ICARUS collaboration employed the 760-ton T600 detector in a successful 3-year physics run at the underground LNGS laboratory, performing a sensitive search for LSND-like anomalous
ν
e
appearance ...in the CERN Neutrino to Gran Sasso beam, which contributed to the constraints on the allowed neutrino oscillation parameters to a narrow region around 1 eV
2
. After a significant overhaul at CERN, the T600 detector has been installed at Fermilab. In 2020 the cryogenic commissioning began with detector cool down, liquid argon filling and recirculation. ICARUS then started its operations collecting the first neutrino events from the booster neutrino beam (BNB) and the Neutrinos at the Main Injector (NuMI) beam off-axis, which were used to test the ICARUS event selection, reconstruction and analysis algorithms. ICARUS successfully completed its commissioning phase in June 2022. The first goal of the ICARUS data taking will be a study to either confirm or refute the claim by Neutrino-4 short-baseline reactor experiment. ICARUS will also perform measurement of neutrino cross sections with the NuMI beam and several Beyond Standard Model searches. After the first year of operations, ICARUS will search for evidence of sterile neutrinos jointly with the Short-Baseline Near Detector, within the Short-Baseline Neutrino program. In this paper, the main activities carried out during the overhauling and installation phases are highlighted. Preliminary technical results from the ICARUS commissioning data with the BNB and NuMI beams are presented both in terms of performance of all ICARUS subsystems and of capability to select and reconstruct neutrino events.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
ICARUS T600 will be operated as far detector of the Short Baseline Neutrino program at Fermilab (U.S.A.), which foresees three liquid argon time projection chambers along the Booster Neutrino Beam ...line to search for a LSND-like sterile neutrino signal. The detector employs 360 photomultiplier tubes, Hamamatsu model R5912-MOD, suitable for cryogenic applications. A total of 400 PMTs were procured from Hamamatsu and tested at room temperature to evaluate the performance of the devices and their compliance to detect the liquid argon scintillation light in the T600 detector. Furthermore 60 units were also characterized at cryogenic temperature, in liquid argon bath, to evaluate any parameter variation which could affect the scintillation light detection. All the tested PMTs were found to comply with the requirements of ICARUS T600 and a subset of 360 specimens was selected for the final installation in the detector.
Tetraphenyl-butadiene (TPB) is an organic fluorescent chemical compound generally used as wavelength shifter thanks to its extremely high efficiency to convert ultra-violet photons into visible ...light. A common method to use TPB with detectors sensitive to visible light, such as photomultiplier tubes (PMTs), is to deposit thin layers on the device window. To obtain effective TPB layers, different procedures can be used. In this work a specific evaporation technique adopted to coat 8 in convex windows photomultiplier tubes is presented. It consists in evaporating TPB by means of a Knudsen cell, which allows to strictly control the process, and in a rotating sample support, which guarantees the uniformity of the deposition. Simulation results and experimental tests demonstrate the effectiveness of this evaporation technique from the point of view of deposition uniformity and light conversion efficiency.
Abstract
The FAMU experiment aims at an indirect measurement of the Zemach radius of the
proton. The measurement is carried out on muonic hydrogen atoms (μH) produced through the
low-momentum (50–60 ...MeV/c) muon beam a the RIKEN-RAL μ
-
facility. The particle flux plays
an important role in this measurement, as it is proportional to the number of μH atoms
produced, which is the target of the FAMU experimental method. The beam monitor calibration
technique and results, presented here, are meant to extract a reliable estimation of the muon flux
during the FAMU data taking. These measurements were carried out at the CNAO synchrotron in Pavia,
Italy, using proton beams and supported by Monte Carlo simulation of the detector in Geant4.
PDF
