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Quantum efficiency of proposed photoemission semiconductor detector of long-wavelength infrared radiation enhanced by multiple passes of radiation. Device has features of back-to-back heterojunction internal-photoemission (HIP) detector, and Fabry-Perot interferometer. Arrays of devices of this type incorporated into integrated-circuit infrared imaging devices.
Making semiconductor radiation detectors that work at room temperature relies heavily on the deposition and pixelation of electrodes. Electrode patterning of perovskite solar cells widely implements laser scribing techniques, which is a convenient, scalable, and inexpensive technique. However, this method has not found its application in radiation detector patterning yet, and the question whether laser scribing can achieve high-quality patterns with minimum damage to a detector crystal and low interpixel cross-talk remains largely unanswered. To prove that laser scribing is a practical method for electrode patterning on perovskite CsPbBr 3 detectors, we use the material to create a variety of patterns. A very low lateral leakage current (60 nA at 10 V) and high mobility-lifetime product (9.7(3) x 10 -4 cm 2 /V) were observed between the pixel and the guard ring in tests of single-pixel devices with a separation of 200 or 100 μm between the central electrode and the guard ring. The 122 and 136 keV photopeaks in 57 Co gamma-ray spectra were very well resolved with an energy resolution of up to 6.1% at 122 keV. Finally, a further reduction in gap size to 50 mu m is conceivable, but more process optimization is needed.
The search for biosignatures in the atmospheres of exoplanets will be a key focus of future space telescopes that operate in the ultraviolet, visible, and near-infrared bands. Detection of biosignatures requires an instrument with moderate spectral resolving power ($R \sim 100$) and a large bandwidth ($\sim 400$ nm -- $\sim 1.8$ $\mu$m). Additionally, biosignature detection is a photon-starved science; instruments designed for these measurements would ideally combine high optical efficiency with quantum-limited photon detectors (i.e., detectors that exhibit zero dark current). In this work, we report on our efforts to develop energy resolving transition edge sensor (TES)-based detectors designed for biosignature detection. TESs operated as microcalorimeters are compelling detectors for this application. Unlike semiconductor detectors, TESs eliminate the need for dispersive optics and are truly single photon detectors -- fundamental TES noise yields uncertainty in the energies of detected photons, not in the number of detected photons. We introduce TESs designed for this application and discuss the path toward realizing a TES-based dispersionless spectrometer optimized for biosignature detection.
The search for biosignatures in the atmospheres of exoplanets will be a key focus of future space telescopes that operate in the ultraviolet, visible, and near-infrared bands. Detection of biosignatures requires an instrument with moderate spectral resolving power (R ~ 100) and a large bandwidth (~ 400 nm – ~ 1.8 µm). Additionally, biosignature detection is a photon-starved science; instruments designed for these measurements would ideally combine high optical efficiency with quantum-limited photon detectors (i.e., detectors that exhibit zero dark current). In this work, we report on our efforts to develop energy resolving transition edge sensor (TES)-based detectors designed for biosignature detection. TESs operated as microcalorimeters are compelling detectors for this application. Unlike semiconductor detectors, TESs eliminate the need for dispersive optics and are truly single photon detectors – fundamental TES noise yields uncertainty in the energies of detected photons, not in the number of detected photons. We introduce TESs designed for this application and discuss the path toward realizing a TES-based dispersionless spectrometer optimized for biosignature detection.
Position sensitivity enables the correction of response non-uniformities in room-temperature semiconductor detectors caused by crystal defects and other factors. It can also be used to pinpoint the exact location of crystal defects responsible for the response variations. This work describes a technique for revealing and visualizing the detector regions affecting the charge collection efficiency in CdZnTe (CZT), TlBr, and CsPbBr 3 detectors configured as position-sensitive virtual Frisch-grid (VFG) devices. The technique correlates the photopeak events in energy spectra with their spatial distributions inside the detectors using the position information. By selecting the events from narrow energy intervals within a photopeak, we can visualize the detector volumes with particular charge collection efficiencies, which, in turn, correlate with the locations of electrode and crystal defects. Here, we demonstrate this technique in several examples. Columnar structures in the volume plots (position distribution maps) are consistent with signal losses near or at the anode in selected samples of CZT and TlBr. Structures exhibiting a distinct depth dependence are consistent with grain boundaries or other crystal defects.
DRiFT, a Detector Response Function Toolkit, post-processes MCNP output to model detector response. Three primary components: scintillator (focus of FY 21 TED work), gas detectors (focus of this FY), and semiconductor detectors. Capability to model scintillator detectors has previously been demonstrated.
Fluctuations of energy loss by charged particles in lithium-drifted silicon semiconductor detectors
The quest for cost-effective, high performing room temperature semiconductor detector (RTSD) materials for high energy gamma rays has been continuing for more than three decades. The requirements for RTSD materials, however, are more stringent as compared to other applications unrelated to detection of X- and gamma-rays, mainly due to the requirement of thick detectors for sufficient absorption of high-energy electromagnetic radiation and excellent charge-transport properties. The II-VI compound CdZnTe (CZT) with the composition of 10 atomic % Zn (Cd0.9Zn0.1Te) has been the material of choice over the past several years, and it has dominated the commercial market for RTSD materials and detectors. Despite its commercial success as a room temperature radiation detection material, CZT suffers from a lack of compositional homogeneity on both a micro- and macro-scale and the presence of high concentrations of sub-grain boundary (dislocation walls) networks and secondary phases (Te-rich inclusions). This chapter focuses on the presence of performance-limiting defects in CZT that hinder the yield and elevate the cost of high-quality detectors. The presence of such performance-limiting defects has restricted widespread deployment of CZT for a variety of potential applications, particularly for uses of relatively large detectors where the demands on material perfection are significantly greater. In the recent past, replacing some of the tellurium with selenium in the CZT matrix was found to be very effective in drastically reducing the Te-rich secondary phases and dislocation networks, plus
Improvements in the development of x-ray detection devices are described. Emphasis is placed on lowering the temperature in order to achieve better x-ray response. A simplified charge integrator schematic is presented along with supporting tables. By using cryogenic operating temperatures, these x-ray detectors may eventually surpass the performance of the best semiconductor detectors.
An apparatus has been designed and is being fabricated to study the charge composition, fluxes, and energy spectra of light nuclei in the energy region from 1 GeV to 100 GeV. The apparatus essentially consists of an array of a large number of particle detectors operated in coincidence and serving as a charged particle telescope. A mosaic silicon semiconductor detector, a plastic scintillation counter and a lucite Cerenkov detector are used to measure the charges of the incident nuclei. Two one-inch thick CsI detectors are used to study low energy particles. An ionization spectrometer is utilized to measure primary energies in the 1 to 100 GeV energy interval. A gas Cerenkov counter is being designed to distinguish between electrons and protons. It is planned to calibrate the apparatus at an accelerator using particles of known energy.
Study shows the pulse-height degradation of gamma ray spectra in germanium/lithium detectors to be due to electron interaction in the dead layers that exist in all semiconductor detectors. A pulse shape discrimination technique identifies and eliminates these defective pulses.
Ultraviolet (UV) and Extreme Ultraviolet (EUV) detectors are very attractive in astronomy, photolithography and biochemical applications. For EUV applications, most of the semiconductor detectors based on PN or PIN structures suffer from the very short penetration depth. Most of the carries are absorbed at the surface and recombined there due to the high surface recombination before reach the depletion region, resulting very low quantum efficiency. On the other hand, for Schottky structures, the active region starts from the surface and carriers generated from the surface can be efficiently collected. 4H-Sic has a bandgap of 3.26eV and is immune to visible light background noise. Also, 4H-Sic detectors usually have very good radiation hardness and very low noise, which is very important for space applications where the signal is very weak. The E W photodiodes presented in this paper are based on Schottky structures. Platinum (Pt) and Nickel (Ni) are selected as the Schottky contact metals, which have the highest electron work functions (5.65eV and 5.15eV, respectively) among all the known metals on 4H-Sic.
Soft X-ray background in the energy range 0.4 to 10 keV was studied. A payload was developed which uses a wide angle, windowless, cooled, Si(Li) semiconductor detector system. With a resolution of less than 150 eV between 0.3 and 2.0 keV, the system is sensitive to an emission equivalent width of about 10 eV. Carbon and oxygen line emission were detected from the vicinity of the North Galactic Pole and the North Polar Spur.
MCNP radiation transport output is post-processed by DRiFT, a Detector Response Function Toolkit to simulate detailed nuclear instrumentation response. DRiFT can be used to assess the performance and potential limitations of scintillator, gas, and semiconductor detectors under a variety of simulated conditions not easily achievable in a laboratory setting. This work describes new updates in DRiFT for scintillator simulations which focus on the capability to simulate scintillators in current mode, an expansion of trigger options, and the ability to customize individual detector properties in a simulation. These improvements are designed to facilitate the ability to model large arrays of scintillator detectors with higher fidelity than was previously possible and are demonstrated in three examples. The first shows the difference between operating DRiFT in current and pulse mode. In the second example, which is intended to demonstrate deviations in individual detector performance, each detector has properties (PMT gain, optical transport, scintillation yield, etc.) that vary between detectors and are specified in DRiFT. A final example examines how DRiFT could be used to optimize digitizer settings in high rate measurements with split signals using the new common trigger option.
MCNP radiation transport output is post-processed by DRiFT, a Detector Response Function Toolkit to simulate detailed nuclear instrumentation response. DRiFT can be used to assess the performance and potential limitations of scintillator, gas, and semiconductor detectors under a variety of simulated conditions not easily achievable in a laboratory setting. This work describes new updates in DRiFT for scintillator simulations which focus on the capability to simulate scintillators in current mode, an expansion of trigger options, and the ability to customize individual detector properties in a simulation. These improvements are designed to facilitate the ability to model large arrays of scintillator detectors with higher fidelity than was previously possible and are demonstrated in three examples. The first shows the difference between operating DRiFT in current and pulse mode. In the second example, which is intended to demonstrate deviations in individual detector performance, each detector has properties (PMT gain, optical transport, scintillation yield, etc.) that vary between detectors and are specified in DRiFT. A final example examines how DRiFT could be used to optimize digitizer settings in high rate measurements with split signals using the new common trigger option.
Hybrid lead halide perovskites have superior charge transport properties to all-inorganic perovskites, but high-resolution spectroscopic radiation detectors have not been realized. Here we show that surface deep traps severely limit charge collection in formamidinium lead bromide (FAPbBr3) single-crystal devices, despite having a good bulk transport property. Three types of defect on the crystal surface, namely, FA vacancies, uncoordinated lead and Pb-Pb dimers caused by bromide loss, are found to form deep traps, resulting in non-radiative charge recombinations at the metal/perovskite interface. By tailoring the passivation functional groups, we find that ammonium bromide can passivate all these three deep traps on FAPbBr3 surfaces, improving the charge collection efficiency to near unity. The comparable bulk and surface recombination lifetimes indicate that all the surface defects are effectively passivated. Surface passivation also reduces the dark current by 10 times and decreases the dark counts by ~60 times. The energy resolution of the 137Cs spectra acquired using the FAPbBr3 detectors is improved from 5.7% to 1.7% when all the surface defects are passivated without changing the bulk properties, which is the best among solution-grown semiconductor detectors. Surface passivation is stable for more than six months, and FAPbBr3 spectroscopic detectors can operate at unprecedented high temperatures of more than 130 degrees C.
The Athena mission and its X-IFU instrument (X-ray Integral Field Unit) will be positioned at the Sun-Earth Lagrangian point L1, where it will be subject to solar wind (low flux plasma of 95% protons and 5% alpha particles) with energy below 0.1 MeV, and to galactic cosmic rays and solar flares (energetic protons, alpha particles, and electrons) with energies up to hundreds of MeV for protons and the GeV for heavier ions. Some of these particles will go through the satellite and hit the focal plane assembly and hence the detectors. These detectors will be TES (Transition-edge sensor) microcalorimeters, flown for the first time in such an environment. In order to ensure the performance of this type of detectors throughout the duration of such mission, it is critical to study the impact of the radiation on their behavior. Indeed, although a lot of reference material exist for semiconductor detectors such as CCDs, little is currently known about the impact of radiation on TES detectors. These energetic events could cause local heating or damage to the detectors and affect their performance. In this work, we describe how we designed a test campaign to assess the impact of L1 radiation on TES detectors for Athena/X-IFU-like missions and present the results of the tests. Analyses includes assessing changes in the pulse shapes and energy resolution of the detectors measured at 55 mK after several radiation dose steps performed at 4 K.
Cluster counting $(dN/dx)$ is a promising method to enhance particle identification for gaseous detectors, especially in next-generation collider experiments like the FCC-ee, where good $π/K$ separation over a broad momentum range is essential. However, its implementation in large-scale systems has been limited by the challenging requirements for high-resolution signal amplification and readout. This paper presents a 24-channel ultra-low-noise preamplifier board designed for drift tube detectors to enable $dN/dx$ measurements. The three-stage amplification topology employs SiGe transistors and integrates dedicated noise-minimization techniques, achieving a charge gain of 21.11 mV/fC from 0.3 fC to 50 fC, a bandwidth of 542 MHz, and a voltage gain of 47.8 dB. The measured voltage noise density is 0.35 nV/$\sqrt{\textrm{Hz}}$ , surpassing most of the state-of-the-art preamplifiers for gaseous and silicon detectors. Validation tests conducted on the sMDT chambers at the CERN Proton Synchrotron test beam facility demonstrate that the proposed design meets the stringent preamplifier requirements for implementing the $dN/dx$ method in drift-tube detector systems, achieving an equivalent noise charge of 0.14 fC and a signal-to-noise ratio of 73 when operated with a He:iC 4 H 10 (90:10) gas mixture. The design also shows promise for broader application in other gaseous or semiconductor detectors.