Detector Package Research Articles

Finite element analysis of the package structure of HgCdTe infrared focal plane array detector

Reliable material parameters, correct boundary condition settings, and a reasonably simplified numerical model are key to obtain reliable and reasonable analysis results. A new finite element analysis model for the HgCdTe infrared focal plane array detector is presented, which includes the core column. The thermal stress and strain of the new model and current model are analyzed, and their distribution laws are obtained. The results are compared, and the reasons are analyzed, which can provide some references for the simulation of infrared detector package structure.

A study of the signal rising edge produced by a charge sensitive preamplifier connected to a 4H-SiC detector

In a general semiconductor detector system, the output amplitude of the charge-sensitive preamplifier (CSA) is proportional to the total charge induced by incident particles. The rising edge of the output signal provides information on the input current. The shape of the rising edge is not only affected by the carrier drifting but the discharge process of the equivalent capacitance (the detector capacitance and the capacitance caused by the detector package and the connecting cable, namely the stray capacitance) and the input resistance of the CSA. The equivalent capacitance and the input resistance often has a time constant of tens nanoseconds, which significantly affects the rising edge, particularly for fast detectors such as silicon carbide or diamond. This paper describes an α-particle testing system based on a Schottky 4H-SiC detector. The junction capacitance of the detector can be adjusted by changing the bias voltage, and the derivative waveforms of the CSA output are analyzed using an equivalent circuit. The results show that the falling edge of the derivative waveform corresponds to the discharge process of the equivalent capacitance and the input resistance in the circuit. The parameters of the detector capacitance, the stray capacitance and the input resistance can be obtained through fitting the decay time. The duration of the induced current of the detector can be measured from the rising edge of the derivative waveform. By comparing the theoretical and the measured value, the carrier mobility at different bias voltages can be derived.

Scaling waveguide-integrated superconducting nanowire single-photon detector solutions to large numbers of independent optical channels.

Superconducting nanowire single-photon detectors are an enabling technology for modern quantum information science and are gaining attractiveness for the most demanding photon counting tasks in other fields. Embedding such detectors in photonic integrated circuits enables additional counting capabilities through nanophotonic functionalization. Here, we show how a scalable number of waveguide-integrated superconducting nanowire single-photon detectors can be interfaced with independent fiber optic channels on the same chip. Our plug-and-play detector package is hosted inside a compact and portable closed-cycle cryostat providing cryogenic signal amplification for up to 64 channels. We demonstrate state-of-the-art multi-channel photon counting performance with average system detection efficiency of (40.5 ± 9.4)% and dark count rate of (123 ± 34) Hz for 32 individually addressable detectors at minimal noise-equivalent power of (5.1 ± 1.2) · 10-18 W/Hz. Our detectors achieve timing jitter as low as 26ps, which increases to (114 ± 17) ps for high-speed multi-channel operation using dedicated time-correlated single photon counting electronics. Our multi-channel single photon receiver offers exciting measurement capabilities for future quantum communication, remote sensing, and imaging applications.

Characterization of the miniPlanacon XPM85112-S-R2D2 MCP-PMT with custom modified backend electronics

We report the results of the measurements of three pieces of the new Photonis miniPLANACON microchannel-plate photomultipliers (MCP-PMTs) intended for use in the demanding environment of the Large Hadron Collider (LHC) beamline as a part of the AFP Time-of-Flight detector. These photomultipliers were modified in cooperation with the manufacturer by using a custom backend and were subjected to numerous tests, with the focus on the rate capability and crosstalk behaviour. We determined that the two of them with a lower MCP resistance are able to operate without significant saturation at an anode current density of 1μA/cm2. These two are, therefore, suitable for the intended use and are currently installed as part of the AFP detector packages.

Measurement of proton, deuteron, triton, and α particle emission after nuclear muon capture on Al, Si, and Ti with the AlCap experiment

Background: Heavy charged particles after nuclear muon capture are an important nuclear physics background to the muon-to-electron conversion experiments Mu2e and COMET, which will search for charged lepton flavor violation at an unprecedented level of sensitivity. Purpose: The AlCap experiment aimed to measure the yield and energy spectra of protons, deuterons, tritons, and α particles emitted after the nuclear capture of muons stopped in Al, Si, and Ti in the low-energy range relevant for the muon-to-electron conversion experiments. Methods: Individual charged particle types were identified in layered silicon detector packages and their initial energy distributions were unfolded from the observed energy spectra. Results: The proton yields per muon capture were determined as Yp(Al)=26.64(28stat.)(77syst.)×10−3 and Yp(Ti)=26.48(35)(80)×10−3 in the energy range 3.5–20.0 MeV, and as Yp(Si)=52.5(6)(18)×10−3 in the energy range 4.0–20.0 MeV. Detailed information on yields and energy spectra for all observed nuclei are presented in the paper. Conclusions: The yields in the candidate muon stopping targets, Al and Ti, are approximately half of that in Si, which was used in the past to estimate this background. The reduced background allows for less shielding and a better energy resolution in these experiments. It is anticipated that the comprehensive information presented in this paper will stimulate modern theoretical calculations of the rare process of muon capture with charged particle emission and inform the design of future muon-to-electron conversion experiments.12 MoreReceived 23 October 2021Accepted 4 March 2022DOI:https://doi.org/10.1103/PhysRevC.105.035501©2022 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasElectron & muon captureLepton induced nuclear reactionsPhysical SystemsMuonic atoms & moleculesParticles & FieldsNuclear Physics

Thermal calibration of the MEDA-TIRS radiometer onboard NASA's Perseverance rover

This article describes a comprehensive testing method for the thermal calibration of the Thermal InfraRed Sensor (TIRS) onboard NASA's Perseverance rover. Ground-based IR detectors operating at the surface of Mars are subjected to inaccuracies caused by the inclusion of thermal gradients in their packages. To reduce such uncertainties, it is necessary to compensate for their effects. Here, details of the TIRS thermo-mechanical design and a simplified thermal mathematical model (TMM) that accounts for the presence of thermal gradients in the detector's package are provided. Then, a set of equations for the estimation and compensation of thermal gradients are proposed based on the results of the TMM. Thermal calibration tests to identify the mathematical estimators are analyzed, providing details of the test setups and highlighting their limitations and restrictions. Finally, experimental results of the calibration tests are presented, along with the uncertainty sources and potential systematic errors associated with the estimation of the gradients. The results presented here show a significant improvement in the accuracy of TIRS versus previous work, thus fulfilling of the radiometer scientific requirements set by the Mars 2020 science team.

Cadmium Zinc Telluride detectors for a next-generation hard X-ray telescope

We are currently developing Cadmium Zinc Telluride (CZT) detectors for a next-generation space-borne hard X-ray telescope which can follow up on the highly successful NuSTAR (Nuclear Spectroscopic Telescope Array) mission. Since the launch of NuSTAR in 2012, there have been major advances in the area of X-ray mirrors, and state-of-the-art X-ray mirrors can improve on NuSTAR’s angular resolution of ∼ 1arcmin Half Power Diameter (HPD) to 15” or even 5” HPD. Consequently, the size of the detector pixels must be reduced to match this resolution. This paper presents detailed simulations of relatively thin (1mm thick) CZT detectors with hexagonal pixels at a next-neighbor distance of 150 μm. The simulations account for the non-negligible spatial extent of the deposition of the energy of the incident photon, and include detailed modeling of the spreading of the free charge carriers as they move toward the detector electrodes. We discuss methods to reconstruct the energies of the incident photons, and the locations where the photons hit the detector. We show that the charge recorded in the brightest pixel and six adjacent pixels suffices to obtain excellent energy and spatial resolutions. The simulation results are being used to guide the design of a hybrid application-specific integrated circuit (ASIC)-CZT detector package.

Photon counting detector package based on InGaAs/InP avalanche structure for laser ranging applications.

Satellite Laser Ranging (SLR) is a well established space geodetic technique measuring the satellite distance, which implements time of flight. Up to now, second harmonic Nd:YAG laser pulses have been frequently used for range measurement, since the silicon detector technology allows us to detect single photon echoes reflected from satellites with required high detection probability, millimeter precision, and an acceptable dark count rate. On the other hand, the fundamental wavelength (1064 nm) provides a significantly better overall energy budget, but there were no suitable detectors available. More recently, the use of InGaAs/InP became feasible for developing single photon avalanche diodes, which exhibit high photon detection probability and acceptable timing resolution. Both these properties are important and allow the SLR measurement at the fundamental wavelength. In this Note, we report on construction and testing of a single photon detector package based on the InGaAs/InP diode optimized for the SLR measurement.

Improved limits on Fierz interference using asymmetry measurements from the Ultracold Neutron Asymmetry (UCNA) experiment

The Ultracold Neutron Asymmetry (UCNA) experiment was designed to measure the β-decay asymmetry parameter, A0, for free neutron decay. In the experiment, polarized ultracold neutrons are transported into a decay trap, and their β-decay electrons are detected with ≈4π acceptance into two detector packages which provide position and energy reconstruction. The experiment also has sensitivity to bn, the Fierz interference term in the neutron β-decay rate. In this work, we determine bn from the energy dependence of A0 using the data taken during the UCNA 2011–2013 run. In addition, we present the same type of analysis using the earlier 2010 A dataset. Motivated by improved statistics and comparable systematic errors compared to the 2010 data-taking run, we present a new bn measurement using the weighted average of our asymmetry dataset fits, to obtain bn=0.066±0.041stat±0.024syst which corresponds to a limit of −0.012<bn<0.144 at the 90% confidence level.Received 17 November 2019Accepted 25 February 2020DOI:https://doi.org/10.1103/PhysRevC.101.035503©2020 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasBeta decayElectroweak interactions in nuclear physicsNuclear tests of fundamental interactionsNuclear Physics

A detector for shielded fission sources

Abstract In recent years, a great deal of attention has been given to the passive detection of fissile material by detecting spontaneously emitted neutrons. Neutron detection schemes generally rely on low-density detection media with high neutron-gamma discrimination capability. However, such detectors generally suffer from low efficiency for high energy (>1.00 MeV) neutrons and usually are constructed with moderating material built into the detector package to compensate for that. But when the source is highly shielded by hydrogenous materials, the moderating material surrounding the detector actually decreases the detector efficiency (Rees and Czirr, 2012). This problem is further compounded if the source is shielded with borated material, significantly reducing the number of emerging neutrons. We have built, tested, and modeled a simple neutron detector that uses a large block of plastic scintillator fitted with a removable cadmium foil. This detector is sensitive to fission gammas, gammas emitted from neutron capture in shielding, gammas emitted from neutron capture in the plastic scintillator, and gammas produced by neutron capture in the cadmium foil. We demonstrate that by applying suitable data analysis, we can detect a shielded californium source with a very small chance of false positives from typical gamma sources . When boron is added to the shielding, we also use the 477 keV gammas emitted when neutrons capture in boron. This process is enhanced by using an auxiliary NaI gamma detector . Although the detection method flies in the face of currently promoted detectors, it is a simple technique that could be applied to a variety of detection applications.

The Focal-Plane Detector Package on the TUNL Split-Pole Spectrograph

A focal-plane detector for the Enge split-pole spectrograph at the Triangle Universities Nuclear Laboratory has been designed. The detector package consists of two position-sensitive gas avalanche counters: a gas proportionality energy loss section and a residual energy scintillator. This setup allows both particle identification and focal-plane reconstruction. In this paper, we will detail the construction of each section along with their accompanying electronics and data acquisition. Effects of energy loss throughout the detector, ray-tracing procedures, and resolution as a function of fill pressure and bias voltage are also investigated. A measurement of the 27Al $(d,p)$ reaction is used to demonstrate a detector performance and to illustrate a Bayesian method of energy calibration.

Revealing Color Forces with Transverse Polarized Electron Scattering.

The Spin Asymmetries of the Nucleon Experiment measured two double spin asymmetries using a polarized proton target and polarized electron beam at two beam energies, 4.7 and 5.9GeV. A large-acceptance open-configuration detector package identified scattered electrons at 40° and covered a wide range in Bjorken x (0.3<x<0.8). Proportional to an average color Lorentz force, the twist-3 matrix element, d[over ˜]_{2}^{p}, was extracted from the measured asymmetries at Q^{2} values ranging from 2.0 to 6.0 GeV^{2}. The data display the opposite sign compared to most quark models, including the lattice QCD result, and an unexpected scale dependence. Furthermore, when combined with the neutron data in the same Q^{2} range the results suggest a flavor independent average color Lorentz force.

Final results for the neutron β-asymmetry parameter A0 from the UCNA experiment

The UCNA experiment was designed to measure the neutron β-asymmetry parameter A0 using polarized ultracold neutrons (UCN). UCN produced via downscattering in solid deuterium were polarized via transport through a 7 T magnetic field, and then directed to a 1 T solenoidal electron spectrometer, where the decay electrons were detected in electron detector packages located on the two ends of the spectrometer. A value for A0 was then extracted from the asymmetry in the numbers of counts in the two detector packages. We summarize all of the results from the UCNA experiment, obtained during run periods in 2007, 2008–2009, 2010, and 2011–2013, which ultimately culminated in a 0.67% precision result for A0.

Abstract 3272: A graph remapping framework for in silico adjudication of SNVs, INDELs, and structural variants from genetic sequencing data

Abstract Several state-of-the-art, easy to use tools are available both for short-variant detection (e.g. GATK, FREEBAYES), and structural variant (SV) detection (e.g. LUMPY, MANTRA, DELLY), but these tools often produce divergent variant calls, especially INDELs, and it is very difficult to reconcile such variants into a single, accurate set. Furthermore, while it would be highly desirable to also detect larger, structural variants (SV), existing SV detector packages are typically difficult to integrate, highly resource-intensive to run, and result in call sets that require expert manual review to reduce false positive detection rate. Our algorithm, GRAPHITE (https://github.com/dillonl/graphite) requires as input a collection of variant calls, made by one or more short-variant or SV detection tools. Typically, this starting set is high sensitivity (i.e. inclusive), but low specificity (i.e. have a high false discovery rate). We then apply a novel “variant adjudication” procedure to discard false positives, while keeping true positive calls. This is accomplished by constructing a graph from these variants (the Variant Graph) representing allelic variants as graph branches, in addition to the branches formed by the current, linear genome reference sequence. Using a graph mapping algorithm (GSSW, a graph extension of the Smith-Waterman alignment algorithm) we developed earlier, we re-map all reads from each of the samples contributing to the candidate calls. We retain candidate variants confirmed by mappings to those branches in the graph that represent the corresponding variant allele, and discard those candidates that were not confirmed by such mappings. This procedure results in a highly specific callset that also maintains the high sensitivity of the inclusive starting callset constructed by multiple primary variant calling methods. Because the graph construction and mapping approach works for most types of SVs in addition to all short variants, variants of all different types can be integrated in a single step. Here we present the application of this method for cross-validating structural variants calls from Pacific Biosciences data by remapping deep Illumina WGS read sets to Variant Graphs constructed using the candidate Pacific Biosciences variants, as part of the Human Genome Structural Variation Consortium (HGSVC) data analysis project. We also present GRAPHITE's application to improving the accuracy of allele frequency measurement in tumor sequencing data, which is essential for the accurate reconstruction of subclonal evolution in longitudinal tumor samples. Citation Format: Dillon Lee, Yi Qiao, Gabor Marth. A graph remapping framework for in silico adjudication of SNVs, INDELs, and structural variants from genetic sequencing data [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3272.

The Focal-Plane Detector Package on the TUNL Split-Pole Spectrograph

A focal plane detector for the Enge Split-pole Spectrograph at Triangle Universities Nuclear Laboratory has been designed. The detector package consists of two position sensitive gas avalanche counters, a gas proportionality energy loss section, and a residual energy scintillator. This setup allows both particle identification and focal plane reconstruction. In this paper we will detail the construction of each section along with their accompanying electronics and data acquisition. Effects of energy loss throughout the detector, ray tracing procedures, and resolution as a function of fill pressure and bias voltage are also investigated. A measurement of the $^{27}\!$Al$(d,p)$ reaction is used to demonstrate detector performance and to illustrate a Bayesian method of energy calibration.

Characterization of SiPMs With NIR Long-Pass Interferential and Plastic Filters

In this paper, we report on the performances of silicon photomultipliers (SiPMs) with commercial long-pass interferential and plastic filters integrated on the detector's package for environmental light rejection. Several applications, including functional near infrared (NIR) spectroscopy or light detection and ranging, would benefit from the use of highly sensitive detectors like SiPMs with optimized electro-optical characteristics in NIR wavelength range. To this purpose, it is fundamental to reduce the absorption of environmental spurious light leading in application to a decrease of the detector's sensitivity, especially for very weak photon fluxes. We will show how the use of both types of filters has a relevant impact on the electro-optical performances of the bare detectors, in terms of cross talk reduction at high overvoltage values, detection efficiency, spectral response and capability to shield effectively the devices from the absorption of stray light, at the different light wavelengths used for the measurements.

An energy analyzing detector for cold neutrons

We describe the design, fabrication, and performance of an energy analyzing detector package for cold neutron spectrometers at the NIST Center for Neutron Research (NCNR). The detector package consists of arrays of highly oriented pyrolytic graphite crystals set at takeoff angles corresponding to different neutron energies. Neutrons incident down the array will be selected out by the appropriate crystal and directed onto an associated neutron detector. The arrays are capable of binning neutrons into one of 54 bins over an energy range of 2.29 meV to 5.11 meV.We describe theory of operation, the development of a highly efficient ultrathin neutron sensor, and the development of the arrays themselves. We present preliminary results for this detector array along with a mature design of the scintillator neutron detector. We also present enhancements we are pursuing prior to deployment of this technology.

Impact of long-pass interferential filters on dark current and background light rejection in Silicon Photomultipliers

There is an increasing interest in using Silicon Photomultipliers (SiPMs) in emerging applications where the detectors have to operate in ambient environment with high sensitivity and fast timing response in combination with narrow bandwidth light emitting sources like LEDs or VCSELs. The need to use large area detectors for optimizing the light collection efficiency, due to the low optical fluxes to be usually detected, imposes the optimization of the SiPM performance in specific wavelength ranges (usually visible or near infrared), to fully exploit the single photon sensitivity of these detectors and not to reduce at the same time their dynamic range. The use of proper optical long-pass filters on the detector's package can represent a suitable way to reach both these targets, through the reduction of environmental light absorption. Here we present the preliminary results obtained from the characterization of n+-p SiPMs with commercial long-pass filters with increasing cut-on wavelength in the range 500 nm–900 nm glued on the top side of the detector's package. The performance of the detectors has been evaluated in terms of dark current variation induced by the use of the filters and background light rejection under the illumination of white fluorescent lamps. The relevant reduction observed in the dark current (up to 90% at 13 V overvoltage) and the consistent reduction of stray light absorption (up to 90% at 3 V overvoltage with a 900 nm cut-on wavelength long-pass filter) are the main characterization results obtained and shown in this paper.

Rapid Detection for Toxicity of Melamine Contamination in Infant formula and Liquid Milk based on Fiber Chemical Sensor

Melamine has become as one of the major food adulterants. Therefore in this article, we developed a novel method for detecting the milk contaminants like toxicity of melamine and classified it based on data spectroscopy. The developed system based on optical fiber sensor, Optical spectroscopy and artificial neural network (ANN). The system consists of an optical source, refractive index sensor (RIS), optical detector (photodiode), spectroscopy data and neural package. Where the detection and classification process depends on the read out of the RIS sensor and near-infrared spectroscopies to achieve the detection and recognition of all the samples by using LM-BP neural network algorithm. The classification rate was reported at accuracy rate reach above 99.98%.

Advanced processing of CdTe pixel radiation detectors

We report a fabrication process of pixel detectors made of bulk cadmium telluride (CdTe) crystals. Prior to processing, the quality and defect density in CdTe material was characterized by infrared (IR) spectroscopy. The semiconductor detector and Flip-Chip (FC) interconnection processing was carried out in the clean room premises of Micronova Nanofabrication Centre in Espoo, Finland. The chip scale processes consist of the aluminum oxide (Al2O3) low temperature thermal Atomic Layer Deposition (ALD), titanium tungsten (TiW) metal sputtering depositions and an electroless Nickel growth. CdTe crystals with the size of 10×10×0.5 mm3 were patterned with several photo-lithography techniques. In this study, gold (Au) was chosen as the material for the wettable Under Bump Metalization (UBM) pads. Indium (In) based solder bumps were grown on PSI46dig read out chips (ROC) having 4160 pixels within an area of 1 cm2. CdTe sensor and ROC were hybridized using a low temperature flip-chip (FC) interconnection technique. The In-Au cold weld bonding connections were successfully connecting both elements. After the processing the detector packages were wire bonded into associated read out electronics. The pixel detectors were tested at the premises of Finnish Radiation Safety Authority (STUK). During the measurement campaign, the modules were tested by exposure to a 137Cs source of 1.5 TBq for 8 minutes. We detected at the room temperature a photopeak at 662 keV with about 2 % energy resolution.