A large number of particle detectors employ liquid argon as their target material owing to its high scintillation yield and its ability to drift ionization charge over large distances. Scintillation ...light from argon is peaked at 128 nm and a wavelength shifter is required for its efficient detection. In this work, we directly compare the light yield achieved in two identical liquid argon chambers, one of which is equipped with polyethylene naphthalate (PEN) and the other with tetraphenyl butadiene (TPB) wavelength shifter. Both chambers are lined with enhanced specular reflectors and instrumented with SiPMs with a coverage fraction of approximately 1%, which represents a geometry comparable to the future large scale detectors. We measured the light yield of the PEN chamber to be 39.4
±
0.4(stat)
±
1.9(syst)% of the yield of the TPB chamber. Using a Monte Carlo simulation this result is used to extract the wavelength shifting efficiency of PEN relative to TPB equal to 47.2
±
5.7%. This result paves the way for the use of easily available PEN foils as a wavelength shifter, which can substantially simplify the construction of future liquid argon detectors.
All camera designs for Small-Sized telescopes (SSTs) proposed for the Cherenkov Telescope Array (CTA) utilize silicon photomultipliers (SiPM) as their baseline photon sensor technology. The ...dual-mirror SST (SST-2M) has a smaller plate scale (i.e. image size) than the single-mirror SST, allowing it to employ 2,000 square SiPMs with pixel sizes of approximately 6 mm, close to the mainstream SiPM sizes.
In CTA, the night sky background level of typically ∼25 Mcounts/s/pixel (>100 Mcounts/s/pixel at maximum) places severe constraints on the trigger capability due to accidental coincidence on neighboring pixels. In order to suppress such events, it is necessary to reduce optical crosstalk, a mechanism whereby a single optical photon can produce multiple avalanches in the SiPM, while keeping good photon detection efficiency. These are, in general, contradicting requirements.
In this manuscript, we report on characterization of a variety of SiPM technologies for SST-2M cameras and compare results obtained at different participating institutions. We assess the harmonization of results and discuss the likely performance that will be achieved for the first production cameras.
•Scaling of SiPM parameters with known factors helps to find other unknown factors.•Lower breakdown SiPM yields better photon detection efficiencies at lower crosstalk.•The SiPM optical crosstalk can be reduced by thicker protection coating above 100 μm.•Lower breakdown SiPM yields better photon detection efficiencies at lower crosstalk.
SiPM-based readouts are becoming the standard for light detection in particle detectors given their superior resolution and ease of use with respect to vacuum tube photo-multipliers. However, the ...contributions of noise detection such as the dark rate, cross-talk, and after-pulsing (AP) may significantly impact their performance. In this work, we present the development of highly reflective single-phase argon chambers capable of displaying light yields up to 32 photo-electrons per keV, with approximately 12 being primary photo-electrons generated by the argon scintillation, while the rest are accounted by optical cross-talk. Furthermore, the presence of compound processes results in a generalized Fano factor larger than 2 already at an over-voltage of 5 V. Finally, we present a parametrization of the optical cross-talk for the FBK NUV-HD-Cryo SiPMs at 87 K that can be extended to future detectors with tailored optical simulations.
Liquefied noble gases are widely used as detector media in various physics experiments owing to their high scintillation efficiency and ease of scalability to large volumes. Now-a-days, these ...experiments are gradually shifting to SiPM-based readouts because of their high photon detection efficiency, superior resolution, and relative ease of use. However, SiPMs emit photons during the avalanche process, known as optical cross-talk, which can significantly affect the measured signal. In this work, we present two small single-phase liquid argon chambers equipped with SiPM arrays. They display high gross light yields up to 32 photo-electrons per keV, with ∼12 attributed to primary photo-electrons generated by scintillation photons. We then present the full parametrization of the over-voltage dependence of the light yield, energy resolution, and optical cross-talk, based on dedicated measurements of optical cross-talk components and a simple analytical model.
Abstract Aria is a plant hosting a $${350}\,\hbox {m}$$ 350 m cryogenic isotopic distillation column, the tallest ever built, which is being installed in a mine shaft at Carbosulcis S.p.A., ...Nuraxi-Figus (SU), Italy. Aria is one of the pillars of the argon dark-matter search experimental program, lead by the Global Argon Dark Matter Collaboration. It was designed to reduce the isotopic abundance of $${^{39}\hbox {Ar}}$$ 39 Ar in argon extracted from underground sources, called Underground Argon (UAr), which is used for dark-matter searches. Indeed, $${^{39}\hbox {Ar}}$$ 39 Ar is a $$\beta $$ β -emitter of cosmogenic origin, whose activity poses background and pile-up concerns in the detectors. In this paper, we discuss the requirements, design, construction, tests, and projected performance of the plant for the isotopic cryogenic distillation of argon. We also present the successful results of the isotopic cryogenic distillation of nitrogen with a prototype plant.
The physical and mechanical properties of two varieties of green banana fruit, namely, Dwarf Scavendish and Nendran, were determined. The average pulp and peel moisture content were 264.17% (db) and ...666.28% (db), respectively for Dwarf Scavendish and 153.39% (db) and 516.41% (db), respectively for Nendran. At these average moisture contents, the average pulp to peel ratios were 1.39 and 2.32, and peel thickness were 3.65 mm and 2.95 mm, respectively. The maximum diameter of fruit without peel was 23.34 mm and 37.08 mm, and average pulp specific gravity was 0.993 and 1.110, respectively for the two varieties. The maximum effective length and width of the banana pulp resting at its most stable position was observed to be 137.0 mm and 66.5 mm, respectively for Dwarf Scavendish and 194.5 mm and 50.0 mm, respectively for Nendran.
The maximum load required to cut a cross-sectional slice of pulp was 22.4 N and 28.2 N for the two varieties, respectively. Maximum energy of 686.81 J/m
2 for Dwarf Scavendish and 724.46 J/m
2 for Nendran was required to cut a slice of the fruit. The banana kept in a convex position required the most energy to cut, whereas the plain position was observed to be the best position
vis-à-vis the energy requirement and consumer preference of chip shape.
In this work we will document the design and the performances of a SiPM-based photodetector with a surface area of 100 cm\(^2\) conceived to operate as a replacement for PMTs. The signals from 94 ...SiPMs are summed up to produce an aggregated output that exhibits in liquid nitrogen a dark count rate (DCR) lower than 100 cps over the entire surface, a signal to noise ratio better than 13, and a timing resolution better than 5.5 ns. The module feeds about 360 mW at 5 V with a dynamic range in excess of 500 photo-electrons on a 100 \(\Omega\) differential line. The unit is compatible with operations at room temperature, with a DCR increased by about 6 orders of magnitude.
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