Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “READOUT”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,513 records · Page 84

Development of a neutron spectrometer utilizing rubberized Eu:LiCAF wafers

A portable ten-layer neutron spectrometer has been developed using a novel material, LiCAF. The spectrometer consists of rubber matrix wafers with embedded europium doped lithium calcium aluminum uoride (Eu:LiCAF) crystals and crosshatched wave shifting fibers (WSF). Layers of high density polyethylene (HDPE) separating each Eu:LiCAF wafer serve as neutron moderating material. Neutrons entering the spec- trometer react in the Eu:LiCAF crystal, creating scintillation photons. The photons travel down the WSFs to silicon photomultipliers (SiPMs) that convert the photons to an electrical signal. Custom electronics are used to gather, amplify, process, and readout the signal. A library of several neutron response curves was created in Geant4 and MCNP. The experimental output of the spectrometer was unfolded using a maximum entropy algorithm, MAXED. The spectrometer was tested using two separate DD generators. These two tests resulted in unfolded neutron spectra with average neutron energies of 2.71 and 2.78 MeV and chi-squared values of 0.88 and 1.51 χ 2 /D.O.F. respectively, when fit to a 2.45 MeV monoenergetic energy spectrum.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Application of deconvolution to recover frequency-domain multiplexed detector pulses

Multiplexing of radiation detectors reduces the number of readout channels, which in turn reduces the number of digitizer input channels for data acquisition. We recently demonstrated frequency domain multiplexing (FDM) of pulse mode radiation detectors using a resonator that converts the detector signal into a damped sinusoid by convolution. The detectors were given unique “tags” by the oscillation frequency of each resonator. The charge collected and the time-of-arrival of the detector pulse were estimated from the corresponding resonator output in the frequency domain. In this paper, we demonstrate a new method to recover the detector pulse from the damped sinusoidal output by deconvolution. Deconvolution converts the frequency-encoded detector signal back to the original detector pulse. We have developed a new prototype FDM system to multiplex organic scintillators based on convolution and deconvolution. Using the new prototype, the charge collected under the anode pulse can be estimated from the recovered pulse with an uncertainty of about 4.4 keVee (keV electron equivalent). The time-of-arrival can be estimated from the recovered pulse with an uncertainty of about 102 ps. We also used a CeBr3 inorganic scintillator to measure the Cs-137 gamma spectrum using the recovered pulses and found a standard deviation of 13.8 keV at 662 keV compared to a standard deviation of 13.5 keV when the original pulses were used. Coincidence measurements with Na-22 using the deconvolved pulses resulted in a timing uncertainty of 617 ps compared to an uncertainty of 603 ps using the original pulses. Pulse shape discrimination was also performed using Cf-252 source and EJ-309 organic scintillator pulses recovered by deconvolution. In conclusion, a figure of merit value of 1.08 was observed when the recovered pulses were used compared to 1.2 for the original pulses.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Timing and synchronization of the DUNE neutrino detector

The DUNE neutrino experiment far detector has a fiducial mass of 40 kt. The O(1 M) readout channels are distributed over the 4 x 10kt modules and need to be synchronized to O(10 ns) with a reliable, simple, affordable system. For the majority of channels a simple DC-balanced protocol is used, with clock and synchronization information encoded on the same fibre. The remaining channels use “White Rabbit” (IEEE-1588). Small scale tests show a timing jitter of <100 ps. The DUNE timing system has been successfully prototyped at the ProtoDUNE-SP detector at CERN.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

GADGET: a Gaseous Detector with Germanium Tagging

The Gaseous Detector with Germanium Tagging (GADGET) is a new detection system devoted to the measurement of weak, low-energy β-delayed proton decays relevant for nuclear astrophysics studies. It is comprised of a new gaseous Proton Detector equipped with a Micromegas readout for charged particle detection, surrounded by the existing Segmented Germanium Array (SeGA) for the high-resolution detection of the prompt γ-rays. Here in this work we describe in detail for the first time the design, construction, and operation of the GADGET system, including performance of the Proton Detector. We present the results of a recent commissioning experiment performed with 25 Si beam at the National Superconducting Cyclotron Laboratory (NSCL). GADGET provided low-background, low-energy β-delayed proton detection with efficiency above 95%, and relatively good efficiency for proton-gamma coincidences (2.7% at 1.37 MeV).

β-delayed proton emission↗

A simulation model of front-end electronics for high-precision timing measurements with low-gain avalanche detectors

Here, we report simulation results of a study aiming to optimize parameters of a detector that uses low-gain avalanche detectors (LGAD) for high-precision timing measurements. The detector is assumed to be composed of a 50μm LGAD sensor coupled to front-end readout electronics which is used to measure the time of arrival of minimum ionizing particles. The simulation includes modeling of signal fluctuations in the LGAD sensor, variations of the analog bandwidth and signal-to-noise ratio (SNR) of the front-end electronics, time bin quantization, and radiation damage of the LGAD sensors. Two approaches to measure the timestamp are considered: leading edge and constant fraction. Simulated LGAD pulses before irradiation, and after irradiation with neutron fluences of 5×10 14 n/cm 2 and 1×10 15 n/cm 2 , are studied. The time resolution for a 50μm LGADs was found to be 35 ps for front-end electronics bandwidths larger than 350 MHz and SNRs larger than 30. The time resolution at SNR of 30 for fluences of 5×10 14 n/cm 2 and 1×10 15 n/cm 2 were found to be 31 ps and 37 ps, respectively.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

A high precision calibration of the nonlinear energy response at Daya Bay

A high precision calibration of the nonlinearity in the energy response of the Daya Bay Reactor Neutrino Experiment’s antineutrino detectors is observed. The energy nonlinearity originates from the particle-dependent light yield of the scintillator and charge-dependent electronics response. The nonlinearity model is constrained by γ calibration points from deployed and naturally occurring radioactive sources, the β spectrum from 12 B decays, and a direct measurement of the electronics nonlinearity with a new flash analog-to-digital converter readout system. With this beind said, less than 0.5% uncertainty in the energy nonlinearity calibration is achieved for positrons of kinetic energies greater than 1 MeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

Evaluation of a semiconductor-based atmospheric radioxenon detection system

A prototype radioxenon detection system for beta–gamma coincidence measurements has been designed using a PIPSBox and a pair of coplanar CdZnTe (CZT) detectors. Coincidence events are identified in real-time using a Field-Programmable Gate Array (FPGA). The measurement of 131m Xe and studies on electron backscatter and memory effect in the PIPSBox have been presented previously; this paper details the measurement of 133/133m Xe, 135 Xe, and background. Here, absolute efficiencies were determined, regions of interest were defined, and Minimum Detectable Concentrations (MDC) for all four radioxenon isotopes were calculated. When neglecting interferences between the radioxenons, the prototype system has an estimated MDC of 0.61 ± 0.15 mBq/m 3 for 133 Xe when using gas processing parameters associated with Xenon International, satisfying the CTBTO requirement for sensitivity of ≤1 mBq/m 3 for 133 Xe. Simulation suggests that by increasing number of CZT detectors used by a factor of 16, the MDCs of the system can be improved by a factor of 2-3. The design shows great promise for future improvement and expansion due to its exceptional energy resolution, high background rejection rate, room temperature operation, minimal memory effect, and simple readout electronics.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

The CLAS12 Micromegas Vertex Tracker

The Micromegas Vertex Tracker was designed to improve upon the tracking capabilities of the baseline design of the CLAS12 spectrometer in Hall~B at Jefferson Laboratory. A Barrel Micromegas Tracker made with six concentric cylinders, each made of three 120$^\circ$-sector tiles, surrounds the Silicon Vertex Tracker, and a Forward Micromegas Tracker composed of 6 disks is placed 30~cm downstream of the liquid-hydrogen target. Both trackers sit in a 5~T solenoid magnetic field. All Micromegas elements are based on resistive technology to withstand luminosities up to $10^{35}$~cm$^{-2}$s$^{-1}$, as well as on bulk technology to enforce gain uniformity and mechanical robustness. Due to the high magnetic field, dedicated electronics have been designed and displaced $\sim$2~m away from the detectors. The electronics readout is based on the DREAM ASICs that allow sustained operation up to 20~kHz trigger rate at the maximum luminosity.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

The CLAS12 forward electromagnetic calorimeter

The CLAS12 Forward Detector includes six independent lead-scintillator electromagnetic sampling calorimeters to provide the primary electron trigger and extend the CLAS12 detection capability to photons and neutrons. Each calorimeter package consists of two modules, the legacy Electromagnetic Calorimeter (EC) previously used in the CLAS detector, and a new pre-shower calorimeter (PCAL) located in front of the EC to extend the total detector radiation length, in order to fully absorb the electromagnetic showers induced by electrons with energies up to 12 GeV. Both calorimeters use a novel triangular hodoscope geometry with stereo readout. The PCAL uses an upgraded design to provide the high spatial resolution necessary for reconstructing π 0 and η decays, and neutrons with high efficiency. Here, this paper treats the design, construction, and calibration of the PCAL and the preliminary combined performance of both detectors.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

The CLAS12 Forward Time-of-Flight system

The Forward Time-of-Flight system for the large-acceptance CLAS12 spectrometer in Hall B at the Thomas Jefferson National Accelerator Facility is described. The system is positioned at distances in the range from 6.2 m to 7.2 m from the beam–target interaction point and spans laboratory polar angles from 5 deg → 45 deg and nearly the full azimuth. The system consists of 540 individual scintillation counters with double-ended readout that range in length from 17 cm to 426 cm of discrete widths of 6 cm, 15 cm, and 22 cm, and of discrete thicknesses of 5 cm and 6 cm. We see the effective counter time resolution for passing charged particles varies from 50 ps for the shortest counters at small angles to 200 ps for the longest counters at large angles. The detectors are part of the forward-angle particle identification system for CLAS12 during offline event reconstruction and are a component of the online data acquisition trigger to select final state event topologies with forward-going charged particles.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Strip sensor performance in prototype modules built for ATLAS ITk

ATLAS experiment is preparing an upgrade of its detector for High-Luminosity LHC (HL-LHC) operation. The upgrade involves installation of the new all-silicon Inner Tracker (ITk). In the context of the ITk preparations, more than 80 strip modules were built with prototype barrel sensors. They were tested with electrical readout on a per-channel basis. In general, an excellent performance was observed, consistent with previous ASIC-level and sensor-level tests. However, the lessons learned included two phenomena important for the future phases of the project. First was the need to store and test the modules in a dry environment due to humidity sensitivity of the sensors. The second was an observation of high noise regions for 2 modules. The high noise regions were tested further in several ways, including monitoring the performance as a function of time and bias voltage. Additionally, direct sensor-level tests were performed on the affected channels. The inter-strip resistance and bias resistance tests showed low values, indicating a temporary loss of the inter-strip isolation. A subsequent recovery of the noise performance was observed. Here we present the test details, an analysis of how the inter-strip isolation affects the module noise, and the relationship with sensor-level quality control tests.

47 OTHER INSTRUMENTATION↗

Effects of trapped charge on the signal formation and detection efficiency for subsequent pulses in irradiated silicon sensors

Envisaged high energy physics experiments like the Future Circular Collider require unprecedented radiation hardness of the detectors, as well as short readout time due to high luminosity and occupancy. Silicon has proven to be extremely radiation hard. Sufficient signals can be recorded even at fluences close to 1 ∙ 1 0 16 n e q / cm 2 . Here, the signal formation was studied in silicon strip sensors, irradiated and annealed until the phenomenon of charge multiplication occurred. ATLAS12EC R0 mini sensors were tested by means of edge TCT measurements at temperatures around –20 °C. It was observed that the detection of subsequent signals separated up to several microseconds is altered by the charge trapped during the preceding pulses. The effects of trapped charge on the electrical configuration of a sensor are well known as a polarization or pumping effect in larger band-gap materials like diamond, but is often neglected for silicon at this relatively high temperature. The investigation of the effect created by trapped charges in silicon sensors using subsequent pulses allows to gain information on important parameters such as de-trapping times. Furthermore, it shows a severe impact on the sensor performance in a pile-up scenario. The irradiation fluence and hence the effective doping concentration, the temperature and the amount of initially created charge have a large impact on this phenomenon. The measurements presented help to characterize this phenomenon; particular attention was paid to the application point of view.

47 OTHER INSTRUMENTATION↗

Charge collection study with the ATLAS ITk prototype silicon strip sensors ATLAS17LS

The inner tracker of the ATLAS detector is scheduled to be replaced by a completely new silicon-based inner tracker (ITk) for the Phase-II of the CERN LHC (HL-LHC). The silicon strip detector covers the volume 40 < R < 100 cm in the radial and | z | < 300 cm in the longitudinal directions. The silicon sensors for the detector will be fabricated using the n + -on-p 6-inch wafer technology, for a total of 22,000 wafers. Here, intensive studies were carried out on the final prototype sensors ATLAS17LS fabricated by Hamamatsu Photonics (HPK). The charge collection properties were examined using penetrating 90 Sr β -rays and the ALIBAVA fast readout system for the miniature sensors of 1 cm × 1 cm in area. The samples were irradiated by protons in the 27 MeV Birmingham Cyclotron, the 70 MeV CYRIC at Tohoku University, and the 24 GeV CERN-PS, and by neutrons at Ljubljana TRIGA reactor for fluence values up to 2 × 10 15 n eq /cm 2 . The change in the charge collection with fluence was found to be similar to the previous prototype ATLAS12, and acceptable for the ITk. Sensors with two active thicknesses, 300 μ m (standard) and 240 μ m (thin), were compared and the difference in the charge collection was observed to be small for bias voltages up to 500 V. Some samples were also irradiated with gamma radiation up to 2 MGy, and the full depletion voltage was found to decrease with the dose. This was caused by the Compton electrons due to the 60 Co gamma radiation. To summarize, the design of the ATLAS17LS and technology for its fabrication have been verified for implementation in the ITk. We are in the stage of sensor pre-production with the first sensors already delivered in January of 2020.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Study of CMOS strip sensor for future silicon tracker

Monolithic silicon sensors developed with High-Voltage CMOS (HV-CMOS) processes have become highly attractive for charged particle tracking. Compared with the standard CMOS sensors, HV-CMOS sensors can provide larger and deeper depletion regions that lead to larger signals and faster charge collection. They can provide high position resolution, low material budget, high radiation hardness and low cost that are desirable for high performance tracking in harsh collision environment. Various studies have been conducted to explore the technology feasibility for the large-area tracking systems at future collider experiments. CHESS (CMOS HV/HR Evaluation for Strip Sensor) sensor series have been developed as an alternative solution to the conventional silicon micro-strip detectors for the ATLAS inner tracker upgrade. The first prototype (named CHESS1) was to evaluate the diode geometry and the in-pixel analog electronics. Obtained test results were used to optimize the second prototype (named CHESS2). CHESS2 was implemented with a full digital readout architecture and realized as a full reticle sized monolithic sensor. Here, the basic characteristics of the CHESS2 prototype sensors and their performance in response to different input signals are presented.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Design of a Time-to-Digital Converter ASIC and a mini-DAQ system for the Phase-2 upgrade of the ATLAS Monitored Drift Tube detector

We present the second prototype of a time-to-digital (TDC) ASIC for the upgrade of the ATLAS Monitored Drift Tube (MDT) detector for High-Luminosity LHC operations. Compared to the first prototype, triple modular redundancy has been implemented for the configuration and flow control logic. Here, the total power consumption is increased by less than 10 mW while achieving the same time resolution and channel uniformity. A mini-DAQ system has been built to verify the front-end electronics chain with the new prototype together with other ASICs and boards in triggered mode. Cosmic ray tests with a small-diameter MDT chamber indicate that the configuration and data transmission of the readout electronics perform well. It is expected that this prototype design will be used in the final production.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

A PIPS + SrI 2 (Eu) detector for atmospheric radioxenon monitoring

The PIPS–SrI 2 (Eu) is a prototype atmospheric radioxenon detection system designed at Oregon State University in support of international efforts towards monitoring clandestine nuclear weapon testing activities. This detector aims to address some shortcomings found in currently deployed beta–gamma atmospheric radioxenon detection systems, such as lackluster energy resolution and memory effect, by employing modern detection materials and readout. The system uses a PIPSBox, a silicon-based gas cell, for electron detection, and a pair of ultrabright, D-shaped SrI 2 (Eu) scintillators coupled to silicon photomultipliers for photon detection. A custom eight-channel digital pulse processor equipped with a field programmable gate-array (FPGA) identifies electron–photon coincidences between the volumes in near real-time. Gas samples of the four radioxenon isotopes of interest were independently measured with the PIPS–SrI 2 (Eu) detection system to determine energy resolution and efficiency. Application of FPGA-based coincidence discrimination in near real-time reduced the ambient background count rate by 95.85 ± 0.04%. Using parameters from the Xenon International gas processing unit and assuming a blank sample and zero memory effect the minimum detectable concentrations (MDCs) for the isotopes were calculated to be 0.12 ± 0.03, 0.27 ± 0.05, 0.15 ± 0.02, and 1.00 ± 0.08 mBq/m 3 air for 131m Xe, 133 Xe, 133m Xe, and 135 Xe, respectively. These MDC estimates compare well with other radioxenon detection systems employed in the International Monitoring System (IMS) and indicate that the PIPS–SrI 2 (Eu) is in compliance with the Comprehensive Nuclear Test-Ban-Treaty Organization (CTBTO) sensitivity requirement of ≤ 1 mBq/m 3 for 133 Xe.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

The GALILEO γ-ray array at the Legnaro National Laboratories

GALILEO, a new 4 pi high-resolution gamma-detection array, based on HPGe detectors, has been developed and installed at the Legnaro National Laboratories. The GALILEO array greatly benefits from a fully-digital readout chain, customized DAQ, and a variety of complementary detectors to improve the resolving power by the detection of particles, ions or high-energy gamma-ray transitions. In this paper, a full description of the array, including electronics and DAQ, is presented together with its complementary instrumentation.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

First 3D vector tracking of helium recoils for fast neutron measurements at Super$\mathrm{KEKB}$

Here we present results from the first deployment of novel, high definition, compact gas Time Projection Chambers (TPCs) with pixel chip readout as part of the BEAST II beam background measurement project at SuperKEKB. The TPCs provide detailed 3D imaging of ionization from neutron-induced nuclear recoils in a helium and carbon dioxide target gas mixture at standard temperature and pressure. We present the TPC performance and the neutron backgrounds observed during the initial stage of collider commissioning. We find excellent electron background rejection, leading to background-free nuclear recoil measurements above 50 keV ee , despite the extreme high-background environment. We measure an angular resolution better than 20° for recoil tracks longer than 1.7 mm, corresponding to an average ionization energy of approximately 100 keV ee . We also obtain the full 3D vector direction of helium recoils by utilizing charge profile measurements along the recoil axis, with a correct head/tail assignment efficiency of approximately 80%. With this performance, we present comparisons between measured and simulated event rates, recoil energy spectra, and directional distributions originating from beam–gas and Touschek beam losses at SuperKEKB. We utilize head/tail recognition to distinguish neutron components traveling with positive radial velocity in the Belle II coordinate system from those traveling in the opposite direction. Finally, we present a novel method of discriminating beam–gas interactions from Touschek beam losses that can eliminate the need for dedicated accelerator runs for background measurements. This method is still statistics-limited. However, future studies should be able to verify this method, which in turn could lead to neutron background analysis runs symbiotic with normal Belle II operation. The capabilities demonstrated here also suggest that high definition recoil imaging in gas TPCs is applicable to low energy, low-background experiments, such as directional dark matter searches.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗