- 标题
- 摘要
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- 实验方案
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Design and characterization of small detection modules based on scintillators and WLS bars with SiPM readout for a cosmic ray mini-array
摘要： This paper describes the design and characterization tests of detection modules for a low-cost, easily reconfigurable mini-array for cosmic rays. The basic layout of each individual module is based on a 400 cm2 scintillator tile, optically coupled to a Wavelength Shifter (WLS) bar and a Silicon Photomultiplier (SiPM) for light collection and readout. Low cost solutions, based on the Arduino MEGA board, have been adopted for electronics, triggering and data acquisition, in view of the operation of this facility. The first detection modules, equipped with 4×4 mm2 SiPMs were fully built and characterized. Additional tests were also carried out with photosensors having different sensitive area and technology.
关键词： Scintillators, scintillation and light emission processes (solid, gas and liquid scintillators),Particle detectors,Interaction of radiation with matter
更新于2025-09-23 15:23:52
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Towards a physical model for energy deposition via cosmic rays into sub-K bolometric detectors
摘要： Cosmology space missions have been known to be particularly sensitive to systematic effects arising from the interaction between cosmic rays and highly sensitive detectors below 200 mK. To remove this signal, one must first understand the deposition and dissipation of energy into these detectors. Using a well-known NTD germanium composite bolometer, we simulate the effect of cosmic rays using a radioactive source in the laboratory. Through analysis of experimental data, we find that the glitch signal shape is a function of incoming particle position, as well as the incoming particle energy. We report also on nonlinear effects in the fit, in order to lay the groundwork towards a new physical model for this energy propagation in the bolometer.
关键词： Interaction of radiation with matter,Cryogenic detectors,Systematic effects,Space instrumentation
更新于2025-09-23 15:22:29
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Study of pulsed laser beams and magnetic field on radish seeds
摘要： In this work we report a study on the in?uence of innovative pulsed stresses utilizing an UV laser and a homemade generator of magnetic ?eld on radish seeds (Raphanus sativus L.) growth. We analysed the seed germination and seedling growth. The UV pulsed laser was an excimer KrF operating at 248 nm, 23 ns of pulse duration, with a laser ?uence of about 40 mJ/cm2. The generator of pulsed magnetic ?eld was realized by the electric discharge on a coil of a high voltage capacitor of 150 μF, 60 kV. The magnetic ?eld pulse waveform exhibited damped oscillations at 215 kHz with a maximum intensity of 400 mT. Groups of uniform radish seeds were exposed to laser pulses at ?ve di?erent doses: 30000 shots (KrF/1), 80000 shots (KrF/2), 145000 shots (KrF/3), 225000 shots (KrF/4) and 275000 shots (KrF/5). Other groups were exposed to magnetic ?eld at eight di?erent doses: 3600 shots (MF/1), 7200 shots (MF/2), 10800 shots (MF/3), 14400 shots (MF/4), 18000 shots (MF/5), 21600 shots (MF/6), 32400 kshots (MF/7) and 36000 shots (MF/8). Simultaneously, untreated seeds were used as control. All treatments were performed at room temperature. Both untreated and treated seeds were transferred in Petri dishes and followed for their germination and seedling growth up to 96 h. The results showed that the stress induced by UV laser photons brought a signi?cant stimulation on root growth which may contribute to improve the performance and the productivity of the plants. On the contrary, all physical stresses induced by magnetic ?elds did not have e?ect on seed germination, as well as on cell elongation growth and on hypocotyls in comparison to control seeds.
关键词： Interaction of radiation with matter,Lasers
更新于2025-09-23 15:19:57
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Temperature sensor based on IR-laser reduced Graphene Oxide
摘要： A simple, cost-effective approach to realize a sensitive temperature sensor based on IR laser reduced graphene oxide (IRLrGO) is reported. The sensor has been obtained by irradiating a graphene oxide (GO) film, placed between two thin glass substrates, with a continuous wave diode laser operating at 970 nm along its entire length. A conductive strip, 13 mm long, 300 μm wide and 7 μm thick, has been generated by moving the GO film on an X-Y translator stage with a given velocity with respect to the fixed laser fiber tip position. The laser treatment has given rise to the GO reduction confirmed by the resistance R measurements as well as from SEM, EDX, ATR-FTIR and Raman analyses. The temperature dependence of the conductive strip resistance has been measured in air from 30?C to 80?C and in high vacuum from 80 K to 300 K. The sample acts as a sensitive and low mass Resistance Temperature Detector (RTD). Such a sensor is biocompatible and requires a very low bias (<1 V). While the performances of the IRLrGO temperature sensor are stable under high vacuum conditions at room temperature, its behavior remains to be studied when it operates under different environmental conditions.
关键词： Interaction of radiation with matter,Materials for solid-state detectors,Fiber Lasers
更新于2025-09-23 15:19:57
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The use of optical fibers as passageways for the scintillation light produced in CaF <sub/>2</sub> (Eu) powder in water for low-level tritiated water measurement
摘要： A solid scintillation counting (SSC) system which uses the mixture of CaF2(Eu) powder and tritiated water inside the chamber room will be developed for the measurement of low-level tritiated water. However, the coincidence detection e?ciency and net count rate might be limited by the photon absorption in the chamber of the SSC detector. This paper discusses the feasibility of using light guide ?bers as the optical passageway in the chamber room by Geant4 simulation. The simulation results show that the performance of the detector can be improved by using wavelength-shifting ?bers as optical passageway in the chamber. The detector can maintain a 4.2% coincidence detection e?ciency at a 6 cm chamber thickness, and the detection limit can be as low as 0.47 Bq/mL under 10 min measurement. As a result, using wavelength-shifting ?bers as optical passageways in the chamber room of the SSC system is possible and e?ective.
关键词： Radiation monitoring,Detector modelling and simulations I (interaction of radiation with matter, interaction of photons with matter, interaction of hadrons with matter, etc),Very low-energy charged particle detectors,Solid state detectors
更新于2025-09-16 10:30:52
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Comprehensive diagnostics of hot electron emission from plasmas produced by sub-nanosecond terawatt laser on thin foil metal targets
摘要： Interaction of high-power and high-energy lasers with matter generates plasmas emitting considerable amounts of relativistic electrons. In this contribution such plasmas were produced by PALS kJ laser facility delivering the beam with intensity of the order of 3 · 1016 W · cm?2 in 400 ps on thin foil metal targets. To study the emission of hot electrons in horizontal plane around the target, an array of electron spectrometers was employed to record the electron emission from the plasma in several angles around the target. For experimental determination of the total number of hot electrons escaping from the plasma through the plasma barrier a target probe was used in order to measure the target return current which neutralizes the positive target charge produced by these escaping hot electrons. Together with this diagnostics the femtosecond interferometry was used to obtain spatial electron density pro?les in close proximity to the irradiated target at selected time delays. Interferograms indicated occurrence of plasma density modulations in front of the target and made it possible to calculate the number of electrons contained within thermal fraction of the plasma produced by the laser. The number of these electrons correlates with the ?ux of soft x-ray radiation observed with the use of an x-ray streak camera.
关键词： Plasma diagnostics - probes,Pulsed power,Interaction of radiation with matter,Plasma diagnostics - interferometry, spectroscopy and imaging
更新于2025-09-12 10:27:22
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Mitigation of EC breakdown in the gyrotron transmission line of the ITER Collective Thomson Scattering diagnostic via a Split Biased Waveguide
摘要： In this paper we present the results of the R&D work that has been performed on avoiding electron cyclotron (EC) gas breakdown inside the launcher transmission line (TL) of the ITER collective Thomson scattering (CTS) diagnostic, due to encountering the fundamental EC resonance, which is located inside the port plug vacuum for the baseline ITER magnetic field scenario. If an EC breakdown occurs, this can lead to strong local absorption of the CTS gyrotron beam, as well as arcing inside the ITER vacuum vessel, which must be avoided. Due to the hostile, restrictive, and nuclear environment in ITER, it is not possible to implement the standard method for avoiding EC breakdown - a controlled atmosphere at the EC resonance. Instead, the CTS diagnostic will include a longitudinally-split electrically-biased corrugated waveguide (SBWG) in the launcher transmission line. The SBWG works by applying a transverse DC bias voltage across the two electrically-isolated waveguide halves, causing free electrons to diffuse out of the EC resonant region before they can cause an electron-impact ionisation-avalanche, and thus an EC breakdown. Due to insufficient experimental facilities, the functionality of the SBWG is validated through Monte Carlo electron modelling.
关键词： Interaction of radiation with matter,Nuclear instruments and methods for hot plasma diagnostics,Overall mechanics design (support structures and materials, vibration analysis etc),Detector design and construction technologies and materials
更新于2025-09-12 10:27:22