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At least 199 records · Page 11

Understanding the SNO+ Detector

SNO+, a large liquid scintillator experiment, is the successor of the Sudbury Neutrino Observatory (SNO) experiment. The scintillator volume will be loaded with large quantities of 130 Te, an isotope that undergoes double beta decay, in order to search for neutrinoless double beta decay. In addition to this search, SNO+ has a broad physics program due to its sensitivity to solar and supernova neutrinos, as well as reactor and geo anti-neutrinos. SNO+ can also place competitive limits on certain modes of invisible nucleon decay during its first phase. The detector is currently undergoing commissioning in preparation for its first phase, in which the detector is filled with ultra pure water. This will be followed by a pure scintillator phase, and then a Tellurium-loaded scintillator phase to search for neutrinoless double beta decay. Here we present the work done to model detector aging, which was first observed during SNO. The aging was found to reduce the optical response of the detector. We also describe early results from electronics calibration of SNO+.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Electronics integration for the GE2/1 and ME0 GEM detector systems for the CMS phase-2 muon system upgrade

Abstract The Large Hadron Collider is currently undergoing its High Luminosity upgrade, which is set to increase the instantaneous luminosity by about a factor of five. Consequently, the Compact Muon Solenoid experiment is upgrading its muon spectrometer to cope with the increased muon flux in the forward region. The GE2/1 triple-gas electron multiplier detector, which has recently entered the mass production phase, and the ME0 triple-GEM detector system, which is in the late prototyping phase, are undergoing electronics integration. These proceedings briefly discuss the frontend electronics for the GE2/1 and ME0 detector systems, the electronics integration testing process, and the future plans for the frontend electronics of these two detector systems by the CMS GEM collaboration.

Instruments & Instrumentation↗

A novel use of light guides and wavelength shifting plates for the detection of scintillation photons in large liquid argon detectors

Scintillation light generated as charged particles traverse large liquid argon detectors adds valuable information to studies of weakly-interacting particles. This paper uses both laboratory measurements and cosmic ray data from the Blanche dewar facility at Fermilab to characterize the efficiency of the photon detector technology developed at Indiana University for the single phase far detector of DUNE. The efficiency of this technology was found to be 0.48% at the readout end when the detector components were characterized with laboratory measurements. A second determination of the efficiency using cosmic ray tracks is in reasonable agreement with the laboratory determination. In conclusion, the agreement of these two efficiency determinations supports the result that minimum ionizing muons generate ${\mathcal N}_{phot} = 40,000$ photons/MeV as they cross the LAr volume.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Gas electroluminescence in a dual phase xenon-doped argon detector

Noble element detectors using argon or xenon as the detection medium are widely used in the searches for rare neutrino and dark matter interactions. Xenon doping in liquid argon can preserve attractive properties of an argon target while enhancing the detectable signals with properties of xenon. Here, in this work, we deployed a dual-phase liquid argon detector with up to 4% xenon doping in the liquid and studied its gas electroluminescence properties as a function of xenon concentration. At ∼2% xenon doping in liquid argon, we measured ∼34 ppm of xenon in the gas and observed ∼2.5 times larger electroluminescence signals using vacuum ultraviolet silicon photomultipliers than those in pure argon. Analysis of signals of different wavelengths confirms that the argon gas electroluminescence process is strongly modified by the addition of xenon. We propose an analytical model to describe the underlying energy transfer mechanism in argon-xenon gas mixtures. Lastly, the implications of this measurement for low-energy ionization signal detection will be discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Phase 2 of Comparative NIR Detector Characterization for NGST

In accordance with NASA Grant and Cooperative Agreement Handbook, 1260.75 (c) (3), enclosed please find a citation of publications resulting from research for the above referenced grant entitled, "Phase II of Comparative NIR Detector Characterization for NGST." This list can also be accessed at http://idtl.stsci.edu/publications.htm. This project was completed with the failure of two Rockwell NIR detectors. The originally proposed measurements could not be completed.

Figer, Donald↗

ProtoDUNE Anode Plane Assembly

ProtoDUNE is a test bed for the Deep Underground Neutrino Experiment, an international physics project hosted at the Department of Energy's Fermilab. One of the ProtoDUNE detectors, which are being constructed at CERN, is a single-phase neutrino detector that uses liquid argon. It will require a number of anode plane arrays, special panels made of wire, to detect the signature of a neutrino interaction in the argon bath. This is a glimpse into the process of fabricating these planes, some of which are being created at the University of Wisconsin-Madison. Learn more about the ProtoDUNE detectors here: https://www.symmetrymagazine.org/article/the-biggest-little-detectors

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Differential phase contrast in scanning x-ray microscopy with half-wavelength phase shifter

A method for differential-phase-contrast imaging in scanning x-ray microscopy is proposed. The microfocus beam is produced with an x-ray focusing optics, and a half of the optical aperture is masked with a λ/2 phase shifter. This generates a pair of focused beam at the focal plane, with π phase difference. Combining with a diaphragm in front of the transmission beam detector, differential phase contrast (contrast proportional to the phase-difference between two foci) can be obtained. Preliminary results with a Fresnel zone plate focusing optics at 12.4 keV x-ray energy are shown.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

CMS Forward Pixel Upgrade Electronics and System Testing

This note discusses results of electronics and system testing of the CMS forward pixel (FPIX) detector upgrade for Phase 1. The FPIX detector is comprised of four stand-alone half cylinders, each of which contains frontend readout electronic boards, power regulators, cables and fibers in addition to the pixel modules. All of the components undergo rigorous testing and quality assurance before assembly into the half cylinders. Afterwards, we perform full system tests on the completely assembled half cylinders, including calibrations at final operating temperatures, characterization of the realistic readout chain, and system grounding and noise studies. The results from all these tests are discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Arterial Phase CTA Replacement by a Virtual Arterial Phase Reconstruction from a Venous Phase CTA: Preliminary Results Using Detector-Based Spectral CT

Objective: To assess the feasibility of creating virtual monoenergetic arterial images from venous phase CTA obtained on a detector-based spectral CT scanner and quantitatively compare the signal-to-noise (SNR) and contrast-to-noise (CNR) ratios of the major arteries to those on polyenergetic true arterial phase images. Methods: In this retrospective study, 23 patients (15 men and 8 women, median age 68 years) who underwent triple-phase CTA on a spectral CT scanner for aortic endograft surveillance were included. The venous phase CTA of each study was reconstructed to generate virtual monoenergetic images at various keV, which were compared to true arterial phase CTA images. SNR and CNR of the aortoiliac arteries were evaluated by testing the differences in means and non-inferiority of virtual arterial images to true arterial images. Effective radiation dose was calculated for standard triple-phase studies in comparison with dual-phase and single-phase spectral CT examinations. Results: Virtual monoenergetic images demonstrated non-inferior (P < 0.05) arterial SNR and CNR compared to true arterial images at 40 keV for all arteries, at 45–50 keV for the thoracic and suprarenal aorta, and at 45–55 keV for the infrarenal aorta and iliac arteries. Significantly higher (P < 0.05) arterial attenuation was obtained at 40 keV for the aortoiliac arteries. Mean effective dose for conventional triple-phase studies was 32.5 mSv in comparison with 21.3 mSv for dual-phase non-contrast/venous scans and 11.3 mSv for single-phase venous scans. Conclusions: Detector-based spectral CT enables creation of virtual monoenergetic arterial images from venous phase CTA with equivalent and in some cases significantly higher SNR/CNR of major arteries compared to images from true arterial phase polyenergetic CTA.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Pulse shape discrimination for Gerda Phase I data

The GERDA experiment located at the Laboratori Nazionali del Gran Sasso of INFN searches for neutrinoless double beta (0νββ) decay of 76 Ge using germanium diodes as source and detector. In Phase I of the experiment eight semi-coaxial and five BEGe type detectors have been deployed. The latter type is used in this field of research for the first time. All detectors are made from material with enriched 76 Ge fraction. The experimental sensitivity can be improved by analyzing the pulse shape of the detector signals with the aim to reject background events. This paper documents the algorithms developed before the data of Phase I were unblinded. The double escape peak (DEP) and Compton edge events of 2.615 MeV γ rays from 208Tl decays as well as two-neutrino double beta (2νββ) decays of 76 Ge are used as proxies for 0νββ decay. For BEGe detectors the chosen selection is based on a single pulse shape parameter. It accepts 0.92 ± 0.02 of signal-like events while about 80 % of the background events at Qββ = 2039 keV are rejected. For semi-coaxial detectors three analyses are developed. The one based on an artificial neural network is used for the search of 0νββ decay. It retains 90 % of DEP events and rejects about half of the events around Qββ . The 2νββ events have an efficiency of 0.85±0.02 and the one for 0νββ decays is estimated to be 0.90 +0.05 -0.09 . A second analysis uses a likelihood approach trained on Compton edge events. The third approach uses two pulse shape parameters. The latter two methods confirm the classification of the neural network since about 90 % of the data events rejected by the neural network are also removed by both of them. In general, the selection efficiency extracted from DEP events agrees well with those determined from Compton edge events or from 2νββ decays.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Measurement of the CP-violating phase β s J/ψΦ in B s 0 →J/ψΦ decays with the CDF II detector

We present a measurement of the CP-violating parameter β s J/ψΦ using approximately 6500 B 0 s →J/ψΦ decays reconstructed with the CDF II detector in a sample of pp̄ collisions at √s=1.96 TeV corresponding to 5.2 fb⁻¹ integrated luminosity produced by the Tevatron collider at Fermilab. We find the CP-violating phase to be within the range β s J/ψΦ ϵ [0.02,0.52]∪[1.08,1.55] at 68% confidence level where the coverage property of the quoted interval is guaranteed using a frequentist statistical analysis. This result is in agreement with the standard model expectation at the level of about one Gaussian standard deviation. We consider the inclusion of a potential S-wave contribution to the B 0 s →J/ψK⁺K⁻ final state which is found to be negligible over the mass interval 1.009 s J/ψΦ , we find the B 0 s decay width difference to be ΔΓ s =0.075±0.035(stat)±0.006(syst) ps⁻¹. We also present the most precise measurements of the B 0 s mean lifetime τ (B 0 s )=1.529±0.025(stat)±0.012(syst) ps, the polarization fractions |A0(0)|²=0.524±0.013(stat)±0.015(syst) and |A II (0)|²=0.231±0.014(stat)±0.015(syst), as well as the strong phase δ ⊥ =2.95±0.64(stat)±0.07(syst) rad. In addition, we report an alternative Bayesian analysis that gives results consistent with the frequentist approach.

Aaltonen, T.↗

In-situ characterization of the Hamamatsu R5912-HQE photomultiplier tubes used in the DEAP-3600 experiment

The Hamamatsu R5912-HQE photomultiplier-tube (PMT) is a novel high-quantum efficiency PMT. It is currently used in the DEAP-3600 dark matter detector and is of significant interest for future dark matter and neutrino experiments where high signal yields are needed. We report on the methods developed for in-situ characterization and monitoring of DEAP's 255 R5912-HQE PMTs. This includes a detailed discussion of typical measured single-photoelectron charge distributions, correlated noise (afterpulsing), dark noise, double, and late pulsing characteristics. Finally, the characterization is performed during the detector commissioning phase using laser light injected through a light diffusing sphere and during normal detector operation using LED light injected through optical fibres.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Advanced far infrared blocked impurity band detectors based on germanium liquid phase epitaxy

This research has shown that epilayers with residual impurity concentrations of 5 x 10(sup 13) cm(exp -3) can be grown by producing the purest Pb available in the world. These epilayers have extremely low minority acceptor concentrations, which is ideal for fabrication of IR absorbing layers. The Pb LPE growth of Ge also has the advantageous property of gettering Cu from the epilayer and the substrate. Epilayers have been grown with intentional Sb doping for IR absorption on lightly doped substrates. This research has proven that properly working Ge BIB detectors can be fabricated from the liquid phase as long as pure enough solvents are available. The detectors have responded at reach minimum wavenumbers. Optimization of the Sb doping concentration should further decrease the photoionization energy of these detectors. Ge BIB detectors have been fabricated that respond to 60 cm(exp -1) with low responsivity. Through reduction of the minority residual impurities, detector performance has reached responsivities of 1 A/W. These detectors have exhibited quantum efficiency and NEP values that rival conventional photoconductors and are expected to provide a much more sensitive tool for new scientific discoveries in a number of fields, including solid state studies, astronomy, and cosmology.

Olsen, C. S.↗

Search for 2 ν β β decay of Xe 136 to the 0 1 + excited state of Ba 136 with the EXO-200 liquid xenon detector

EXO-200 is a single phase liquid xenon detector designed to search for neutrinoless ββ decay of 136 Xe to the ground state of 136 Ba. We report here on a search for the two-neutrino ββ decay of 136 Xe to the first 0 + excited state, 0 + 1 , of Ba136 based on a 100 kg yr exposure of 136 Xe. Using a specialized analysis employing a machine learning algorithm, we obtain a 90% CL half-life sensitivity of 1.7×10 24 yr. We find no statistically significant evidence for the 2νββ decay to the excited state resulting in a lower limit of T 2ν 1/2 (0 + → 0 + 1 ) > 6.9 ×10 23 yr at 90% CL. In conclusion, this observed limit is consistent with the estimated half-life of 2.5×10 25 yr.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

Machine Learning-Based Technique for Automated Sensor Characterization

The development of novel instrumentation requires an iterative cycle with three stages: design, prototyping, and testing. Recent advancements in simulation and nanofabrication techniques have significantly accelerated the design and prototyping phases. Nonetheless, detector characterization continues to be a major bottleneck in device development. During the testing phase, a significant time investment is required to characterize the device in different operating conditions and find optimal operating parameters. The total effort spent on characterization and parameter optimization can occupy a year or more of an expert s time. In this work, we present a novel technique for automated sensor calibration that aims to accelerate the testing stage of the development cycle. This technique leverages closed-loop Bayesian optimization (BO), using real-time measurements to guide parameter selection and identify optimal operating states. We demonstrate the method with a novel low-noise CCD, showing that the machine learning-driven tool can efficiently characterize and optimize operation of the sensor in a couple of days without supervision of a device expert.

Zepeda, Cuevas [Chicago U., KICP]↗

Automating Sensor Characterization with Bayesian Optimization

The development of novel instrumentation requires an iterative cycle with three stages: design, prototyping, and testing. Recent advancements in simulation and nanofabrication techniques have significantly accelerated the design and prototyping phases. Nonetheless, detector characterization continues to be a major bottleneck in device development. During the testing phase, a significant time investment is required to characterize the device in different operating conditions and find optimal operating parameters. The total effort spent on characterization and parameter optimization can occupy a year or more of an expert's time. In this work, we present a novel technique for automated sensor calibration that aims to accelerate the testing stage of the development cycle. This technique leverages closed-loop Bayesian optimization (BO), using real-time measurements to guide parameter selection and identify optimal operating states. We demonstrate the method with a novel low-noise CCD, showing that the machine learning-driven tool can efficiently characterize and optimize operation of the sensor in a couple of days without supervision of a device expert.

Cuevas-Zepeda, Julian [Chicago U., KICP; Chicago U↗

Energy calibration of the ProtoDUNE-SP TPC

The single-phase liquid argon prototype at CERN (ProtoDUNE-SP) acts as a validation of the design for the DUNE single-phase far detector. With a total mass of 770 tons, it is the largest monolithic liquid argon single-phase time projection chamber in the world. ProtoDUNE-SP collected test-beam in autumn of 2018 and has been collecting cosmic and special calibration data since the end of 2018. To analyze data from the test-beam, a calibration plan using cosmic muons passing through the detector was developed. An outline of this plan and its impact on the calorimetric measurements of the detector will be discussed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Shuttle orbiter Ku-band radar/communications system design evaluation. Ku band bent-pipe channel performance evaluation

Because of difficulties with the bit detector of the SPA mode 1 channel 3 input port, a new bit synchronizer was required. The two prime candidate designs are described and analyzed. The selected design is a modification of one which utilizes a phase frequency detector to track the received data clock frequency and a mid-bit transition point sample detector to generate a bit timing error (phase error) signal to control the relative phase between the local clock and the local data stream. The model used to calculate the effects of cable attenuation and rise time degradation is discussed.

Holmes, J. K.↗