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Journal of astronomical telescopes, instruments, and systems 8(01), 014007-1 (2022). doi:10.1117/1.JATIS.8.1.014007, The prototype Schwarzschild-Couder Telescope (pSCT) is a candidate for a medium-sized telescope in the Cherenkov Telescope Array. The pSCT is based on a novel dual mirror optics design which reduces the plate scale and allows for the use of silicon photomultipliers as photodetectors. The prototype pSCT camera currently has only the central sector instrumented with 25 camera modules (1600 pixels), providing a 2.68$^{\circ}$ field of view (FoV). The camera electronics are based on custom TARGET (TeV array readout with GSa/s sampling and event trigger) application specific integrated circuits. Field programmable gate arrays sample incoming signals at a gigasample per second. A single backplane provides camera-wide triggers. An upgrade of the pSCT camera is in progress, which will fully populate the focal plane. This will increase the number of pixels to 11,328, the number of backplanes to 9, and the FoV to 8.04$^{\circ}$. Here we give a detailed description of the pSCT camera, including the basic concept, mechanical design, detectors, electronics, current status and first light., Published by SPIE, [Bellingham, Wash.]

The Schwarzschild-Couder Telescope (SCT) is a medium-sized telescope technology proposed for the Cherenkov Telescope Array. It uses a novel dual-mirror optical design that removes comatic aberrations across its entire field of view. The SCT camera employs high-resolution silicon photomultiplier (SiPM) sensors with a pixel size of 4 arcminutes. A prototype SCT (pSCT) has been constructed at the Fred Lawrence Whipple Observatory in Arizona, USA. An observing campaign in 2020, with a partial camera of 1600 pixels (2.7 degrees by 2.7 degrees field of view) resulted in detection of the Crab Nebula at 8.6 sigma statistical significance. Work on the pSCT camera and optical system is ongoing to improve performance and prepare for an upcoming camera upgrade. The pSCT camera upgrade will replace the current camera modules with improved SiPMs and readout electronics and will expand the camera to its full design field of view of 8 degrees in diameter (11,328 pixels). The fully upgraded pSCT will enable next-generation very-high-energy gamma-ray astrophysics through excellent background rejection and angular resolution. In this presentation we describe first results from the successful operation of the pSCT and future plans., 9 pages, 3 figures, 2 tables, contribution to ICRC 2021, similar to 10.1016/j.astropartphys.2021.102562 (arXiv:2012.08448)

We report the results and analysis methods from field-testing the imaging calorimeter prototype for the Advanced Particle-astrophysics Telescope (APT) through an antarctic balloon flight (in the 2019 austral Antarctic balloon season) and through a CERN heavy-ion beam test in 2018. The Advanced Particle-astrophysics Telescope is a proposed space-based gamma- and cosmic-ray instrument that utilizes a novel distributed imaging calorimeter for both particle tracking and energy reconstruction. The imaging CsI calorimeter (ICC) consists of a CsI:Na scintillator read out by (WLS) fibers in both the x- and y-planes. To function both as a gamma-ray and cosmic-ray instrument APT must operate over a large dynamic range, from the single photon-election regime for low energy gamma-ray events to high-$Z$ cosmic-ray events. Analysis of data from a 150 mm x 150 mm prototype instrument (APTlite) on a piggy-back flight on the 2019 SuperTIGER-2.3 balloon instrument provided cosmic ray data that were used to demonstrate the key detector and electronics elements of the ICC. Significantly, analysis of flight data demonstrated the large dynamic range of the instrument, showing the possibility to reconstruct the nuclear charge through analysis of the scintillation tail of saturating high-Z cosmic-ray events by utilizing the deep memory depth available to the TARGET waveform digitizer electronics. Spatial reconstruction of events was performed using a two-sided Voigt profile demonstrating position localization within the imaging calorimeter plane to less 3 WLS fiber widths. Charge resolution was evaluated on a 50 mm x 50 mm prototype placed in the 150 GeV/nuc, A/Z = 2.2 CERN SPS beam line. Nuclei were tagged using HNX/TIGERISS silicon-strip detectors and silicon pad detectors, which allowed for fragmentation cuts in the data. The vastly saturating signals were reconstructed from the CsI:Na scintillation tail and show an APT charge resolution up to Z = 11 (with experimental limitations preventing full evaluation for Z larger 11) and demonstrated no significant non-linearity in the Z$^2$ measurement derived from the CsI:Na optical signal response up to $Z=82$.

We present a pipeline for fast GRB source localization for the Advanced Particle-astrophysics Telescope. APT records multiple Compton scatterings of incoming photons across 20 CsI detector layers, from which we infer the incident angle of each photon's first scattering to localize its source direction to a circle centered on the vector formed by its first two scatterings. Circles from multiple photons are then intersected to identify their common source direction. Our pipeline, which runs in real time on low-power hardware, uses an efficient tree search to determine the most likely ordering of scatterings for each photon (which cannot be measured due to the coarse time-scale of detection), followed by likelihood-weighted averaging and iterative least-squares refinement to combine all circles into an estimated source direction. Uncertainties in the scattering locations and energy deposits require that our pipeline be robust to high levels of noise. To test our methods, we reconstructed GRB events produced by a Geant4 simulation of APT's detectors paired with a second simulator that models measurement noise induced by the detector hardware. Our methods proved robust against noise and the effects of pair production, producing sub-degree localization for GRBs with fluence 0.3 MeV/cm^2. GRBs with fluence 0.03 MeV/cm^2 provided fewer photons for analysis but could still be localized within 2.5 degrees 68% of the time. Localization time for a 1-second 1.0 MeV/cm^2 GRB, measured on a quad-core, 1.4 GHz ARMv8 processor (Raspberry Pi 3B+), was consistently under 0.2 seconds — fast enough to permit real-time redirection of other instruments for follow-up observations.

We present simulations of the instrument performance of the Advanced Particle-astrophysics Telescope (APT), a mission concept of a $\gamma$-ray and cosmic-ray observatory in a sun-Earth Lagrange orbit. The key components of the APT detector include a multiple-layer tracker composed of scintillating fibers and an imaging calorimeter composed of thin layers of CsI:Na scintillators. The design is aimed at maximizing effective area and field of view for $\gamma$-ray and cosmic-ray measurements, subject to constraints on instrument cost and total payload mass. We simulate a detector design based on $3$-meter scintillating fibers and develop reconstruction algorithms for $\gamma$-rays from a few hundreds of $\mathrm{keV}$ up to a few $\mathrm{TeV}$ energies. At the photon energy above $30~\mathrm{MeV}$, pair-production/shower reconstruction is applied; the results show that APT could provide an order of magnitude improvement in effective area and sensitivity for $\gamma$-ray detection compared with the Fermi Large Area Telescope (LAT). A multiple-Compton-scattering reconstruction at photon energies below $10~\mathrm{MeV}$ achieves sensitive detection of faint $\gamma$-ray bursts (GRBs) and other $\gamma$-ray transients down to $\sim0.01~\mathrm{MeV/cm}^2$ with degree-level to sub-degree-level localization accuracy. The Compton analysis also provides a measurement of polarization where the minimum detectable degree of polarization for $\sim1~\mathrm{MeV/cm}^2$ GRBs is below $20\%$. In addition to the APT simulations, we present the simulated performance of the Antarctic Demonstrator for APT, a 0.5m-square cross section balloon experiment that includes all of the key elements of the full APT detector.

We describe the development of a future gamma-ray/cosmic-ray mission called the Advanced Particle-astrophysics Telescope (APT). The instrument will combine a pair tracker and Compton telescope in a single monolithic design. By using scintillating fibers for the tracker and wavelength-shifting fibers to readout CsI detectors, the instrument will achieve an order of magnitude improvement in sensitivity compared with Fermi but with fewer readout channels, and lower complexity. By incorporating multiple Compton imaging over a very large effective area, the instrument will also achieve orders of magnitude improvement in MeV sensitivity compared with other proposed instruments. The mission would have a broad impact on astroparticle physics; primary science drivers for the mission include: (1) probing WIMP dark matter across the entire natural mass range and annihilation cross section for a thermal WIMP, (2) providing a nearly all-sky instantaneous FoV, with prompt sub-degree localization and polarization measurements for gamma-rays transients such as neutron-star mergers and (3) making measurements of rare utra-heavy cosmic ray nuclei to distinguish between n-star merger and SNae r-process synthesis of the heavy elements. We will describe ongoing work including a series of accelerator beam tests, a piggy-back Antactic flight (APTlite) and the recently funded long-duration balloon mission: the Antarctic Demonstrator for APT (ADAPT).

This paper introduces a second-generation balloon-borne hard X-ray polarimetry mission, XL-Calibur. X-ray polarimetry promises to give qualitatively new information about high-energy astrophysical sources, such as pulsars and binary black hole systems. The XL-Calibur contains a grazing incidence X-ray telescope with a focal plane detector unit that is sensitive to linear polarization. The telescope is very similar in design to the ASTRO-H HXT telescopes that has the world’s largest effective area above ~10 keV. The detector unit combines a low atomic number Compton scatterer with a CdZnTe detector assembly to measure the polarization making use of the fact that polarized photons Compton scatter preferentially perpendicular to the electric field orientation. It also contains a CdZnTe imager at the bottom. The detector assembly is surrounded by the improved anti-coincidence shielding, giving a better sensitivity. The pointing system with arcsecond accuracy will be achieved.

The Schwarzschild-Couder Telescope (SCT) is a telescope concept proposed for the Cherenkov Telescope Array. It employs a dual-mirror optical design to remove comatic aberrations over an $8^{\circ}$ field of view, and a high-density silicon photomultiplier camera (with a pixel resolution of 4 arcmin) to record Cherenkov emission from cosmic ray and gamma-ray initiated particle cascades in the atmosphere. The prototype SCT (pSCT), comprising a 9.7 m diameter primary mirror and a partially instrumented camera with 1536 pixels, has been constructed at the Fred Lawrence Whipple Observatory. The telescope was inaugurated in January 2019, with commissioning continuing throughout 2019. We describe the first campaign of observations with the pSCT, conducted in January and February of 2020, and demonstrate the detection of gamma-ray emission from the Crab Nebula with a statistical significance of $8.6\sigma$., Comment: 13 pages, 12 figures, 3 tables, submitted to Astroparticle Physics

A prototype Schwarzschild-Couder Telescope (pSCT) has been constructed at the Fred Lawrence Whipple Observatory as a candidate for the medium-sized telescopes of the Cherenkov Telescope Array Observatory (CTAO). CTAO is currently entering early construction phase of the project and once completed it will vastly improve very high energy gamma-ray detection component in multi-wavelength and multi-messenger observations due to significantly improved sensitivity, angular resolution and field of view comparing to the current generation of the ground-based gamma-ray observatories H.E.S.S., MAGIC and VERITAS. The pSCT uses a dual aspheric mirror design with a $9.7$ m primary mirror and $5.4$ m secondary mirror, both of which are segmented. The Schwarzschild-Couder (SC) optical system (OS) selected for the prototype telescope achieves wide field of view of $8$ degrees and simultaneously reduces the focal plane plate scale allowing an unprecedented compact ($0.78$m diameter) implementation of the high-resolution camera ($6$mm/ $0.067$deg per imaging pixel with $11,328$ pixels) based on the silicon photo-multipliers (SiPMs). The OS of the telescope is designed to eliminate spherical and comatic aberrations and minimize astigmatism to radically improve off-axis imaging and consequently angular resolution across all the field of view with respect to the conventional single-mirror telescopes. Fast and high imaging resolution OS of the pSCT comes with the challenging submillimeter-precision custom alignment system, which was successfully demonstrated with an on-axis point spread function (PSF) of $2.9$ arcmin prior to the first-light detection of the Crab Nebula in 2020. Ongoing and future commissioning activities are reported.

XL-Calibur is a balloon-borne hard X-ray polarimetry mission, the first flight of which is currently foreseen for 2021. XL-Calibur carries an X-ray telescope consists of consists of 213 Wolter I grazing-incidence mirrors which are nested in a coaxial and cofocal configuration. The optics design is nearly identical to the Hard X-ray Telescope (HXT) on board the ASTRO-H satellite. The telescope was originally fabricated for the Formation Flying Astronomical Survey Telescope (FFAST) project. However, the telescope can be used for XL-Calibur, since the FFAST project was terminated before completion. The mirror surfaces are coated with Pt/C depth-graded multilayers to reflect hard X-rays above 10 keV by Bragg reflection. The effective area of the telescope is larger than 300 cm^2 at 30 keV. The mirrors are supported by alignment bars in the housing, and each of the bars has a series of 213 grooves to hold the mirrors. To obtain the best focus of the optics, the positions of the mirrors have to be adjusted by tuning the positions of the alignment bars. The tuning of the mirror positions is conducted using the X-ray beam at the synchrotron facility SPring-8 BL20B2, and this process is called optical tuning. First the positions of the second reflectors are tuned, and then those of the first reflectors are tuned. We did the first optical tuning in Jan 2020. The second tuning will be planned between April to July, 2020. This paper reports the current status of the hard X-ray telescope for XL-Calibur.

The novel 9.7m Schwarzschild-Couder Telescope (SCT), utilizing aspheric dual-mirror optical system, has been constructed as a prototype medium size x-ray telescope for the Cherenkov Telescope Array (CTA) observatory. The prototype SCT (pSCT) is designed to achieve simultaneously the wide (>= 8°) field of view and the superior imaging resolution (0.067 per pixel) to significantly improve scientific capabilities of the observatory in conducting the sky surveys, the follow-up observations of multi-messenger transients with poorly known initial localization and the morphology studies of x-ray sources with angular extent. In this submission, we describe the hardware and software implementations of the telescope optical system as well as the methods specifically developed to align its complex optical system, in which both primary and secondary mirrors are segmented. The pSCT has detected Crab Nebula in June 2020 during ongoing commissioning, which was delayed due to worldwide pandemic and is not yet completed. Verification of pSCT performance is continuing and further improvement of optical alignment is anticipated.

XL-Calibur is a hard X-ray (15-80 keV) polarimetry mission operating from a stabilised balloon-borne platform in the stratosphere. It builds on heritage from the X-Calibur mission, which observed the accreting neutron star GX 301-2 from Antarctica, between December 29th 2018 and January 1st 2019. The XL-Calibur design incorporates an X-ray mirror, which focusses X-rays onto a polarimeter comprising a beryllium rod surrounded by Cadmium Zinc Telluride (CZT) detectors. The polarimeter is housed in an anticoincidence shield to mitigate background from particles present in the stratosphere. The mirror and polarimeter-shield assembly are mounted at opposite ends of a 12 m long lightweight truss, which is pointed with arcsecond precision by WASP - the Wallops Arc Second Pointer. The XL-Calibur mission will achieve a substantially improved sensitivity over X-Calibur by using a larger effective area X-ray mirror, reducing background through thinner CZT detectors, and improved anticoincidence shielding. When observing a 1 Crab source for $t_{\rm day}$ days, the Minimum Detectable Polarisation (at 99% confidence level) is $\sim$2$\%\cdot t_{\rm day}^{-1/2}$. The energy resolution at 40 keV is $\sim$5.9 keV. The aim of this paper is to describe the design and performance of the XL-Calibur mission, as well as the foreseen science programme., Comment: 19 pages, 17 figures. Accepted for publication in Astroparticle Physics

The first prototype of the Schwarzschild Couder Medium Size Telescope (pSCT) proposed for the CTA observatory has been installed in 2018 at the Fred Lawrence Whipple Observatory. The pSCT camera is composed of 25 modules with 64 channels each, covering only a small portion of the full focal plane of the telescope. The Italian Institute of Nuclear Physics (INFN) has developed and characterized in collaboration with Fondazione Bruno Kessler (FBK) a new generation of Silicon Photomultipliers (SiPMs) sensitive to the Near Ultraviolet wavelengths, based on the High Density technology (NUV-HD devices). The latest generation of 6×6 mm2 SiPMs (called NUV-HD3) have been used to equip a subsection of 9 out of 25 modules of the pSCT camera. An upgrade of this camera is foreseen between 2019 and 2020 using the same sensors, aiming to equip the full focal plane with 177 modules, for a total of more than 11000 pixels. We will present a full characterization of the performance of these devices, highlighting why they are suitable for Cherenkov light detection. An overview on the overall behavior of the installed sensors will be also given, providing information on the uniformity of the sensors and of the performance of the camera.

The response to 150 GeV/nuc primary lead ($^{208}$Pb) and fragmented (A/Z=2.4, 2.2, 2.0) beams measured a silicon strip detector, designed for use in the Heavy Nuclei eXplorer (HNX) and an upgrade of the Super Trans-Iron Galactic Element Recorder (SuperTIGER) balloon experiment, was evaluated in a CERN test beam (H8A) during Nov - Dec 2018. The 500 $\mu$m thick, single-sided silicon detectors have 32 DC-coupled strips with 3 mm pitch on the junction side with $9.6 \times 9.6$ cm$^2$ active area. Discrete charge-preamplifiers and shaping amplifiers were used to read out the ohmic and junction side signals simultaneously using the SuperTIGER DAQ system. We report on the response in a configuration where all 32 strips were joined and read out together. The strip detector-under-test was situated between planar silicon detectors, which provided the charge selection as well as a comparison of the measured response of each detector. The combined data set shows excellent charge resolution and finely resolved elemental peaks from helium (Z=2) through lead (Z=82). In this paper, we provide a description of the test beam experiment and the results of the charge resolution analysis.

SuperTIGER (Trans-Iron Galactic Element Recorder) is a large-area balloon-borne instrument built to measure the galactic cosmic-ray (GCR) abundances of elements from Z=10 (Ne) through Z=56 (Ba) at energies from ~0.8 to ~10 GeV/nuc. SuperTIGER flew over Antarctica for a record-breaking 55 days, from December 8, 2012 to February 1, 2013. We will report progress on calculations of galactic cosmic ray spectra corrected to the top of the atmosphere for abundant elements between Ne and Zn from the SuperTIGER flight data. The energy spectra calculations will include up to date refinements to the energy calibrations for the acrylic and aerogel Cherenkov detectors in the instrument, and we will report on new instrument and atmospheric corrections to the top of the atmosphere for energies and abundances. Heinz and Sunyaev (2002) suggested that microquasar jets like those observed in GRS 1915+105 and GRO J1655-40 may be observable as near monoenergetic peaks in heavy ion spectra in the 3-10 GeV/nuc energy range. The large area and long flight duration of SuperTIGER is particularly suited to looking for these microquasar signatures with good statistics. We will compare our SuperTIGER spectra with ACE/CRIS and HEAO-3 spectra and with model GCR spectra solar modulated for the time period of the flight, and we will search for features that may be produced by microquasar jets.

Silicon Photomultipliers (SiPM) are increasingly being used in ground-based astrophysics experiments as a replacement for Photomultiplier tubes (PMTs). These compact low power, rugged sensors are also well suited for space applications and have an added advantage over PMTs in that they do not require high-voltage bias. Efforts are underway at NASA Goddard and our collaborators to develop large-area arrays of SiPMs as the readout for the upcoming funded CubeSat missions such as BurstCube and Terrestrial RaYs Analysis and Detection (TRYAD) and also larger missions including the ultra-heavy cosmic-ray Heavy Nuclei Explorer (HNX) experiment and the gamma-ray Advanced Particle-astrophysics Telescope (APT) experiment. Our team has recently tested SiPMs in a heavy ion beam at CERN. The primary beam consisted of lead ions with energy of ~150 GeV/nuc. SiPM hardware was exposed to both a pure and fragmented Pb beam allowing us to look at ions from Z=1 to Z=82. We report in this paper on direct comparisons with the performance of Hamamatsu R1924A photomultipliers in addition to examining the signals (and subsequent effects) from direct exposure to a lead beam.

The SuperTIGER (Trans-Iron Galactic Element Recorder) experiment was launched for the second time from the Long Duration Balloon (LDB) site near McMurdo Station, Antarctica on December 20, 2018 at 1:36 AM NZDT. The balloon reached a peak altitude of ∼79,300 ft before it began to descend, and the flight had to be terminated after just over six hours aloft. The payload landed at 8:17 AM NZDT approximately 150 miles from McMurdo Station at 75.80 S and 161.68 E. Satellite imagery of the site revealed that it was in a crevasse field, but a Twin Otter reconnaissance flight showed none in the immediate vicinity. A subsequent site survey by a team flown in by helicopter with ground penetrating radar was able to flag a safe zone including helicopter landing sites. The SuperTIGER-2 payload was recovered in two days with two Bell 212 helicopters followed by one day with a Basler, which involved transferring the payload to a safe fixed wing landing site roughly two miles away in three helicopter sling loads. After return to the LDB site the instrument modules were reassembled, rewired and tested prior to their being shipped north. The instrument was found to be in overall good condition, with all testable electronics channels working, and minimal mechanical damage. SuperTIGER-2 could be refurbished to fly again as early as this next Antarctic season.

Near UltraViolet High Density (NUV-HD) SiPMs produced by Fondazione Bruno Kessler in collaboration with INFN have been tested and characterized in INFN laboratories. The third generation of these devices (HD3) has proven to be suitable to equip the focal plane of the prototype Schwarzschild–Couder Medium Size Telescope (pSCT) proposed for the Cherenkov Telescope Array Observatory. Photosensors have been assembled in 4 16-pixel optical units coupled with TARGET–7 ASIC front-end electronics for amplification and digitization of the signal. At present, 9 modules have been successfully integrated on the pSCT camera and are currently taking data. In this contribution we report on the performances of the HD3 technology as single sensor and as assembled optical units, showing their performance and homogeneity in terms of gain and dark count rate.

The Compact High Energy Camera (CHEC) is a camera design for the Small-Sized Telescopes (SSTs; 4 m diameter mirror) of the Cherenkov Telescope Array (CTA). The SSTs are focused on very-high-energy γ -ray detection via atmospheric Cherenkov light detection over a very large area. This implies many individual units and hence cost-effective implementation, as well as shower detection at large impact distance, and hence large field of view (FoV), and efficient image capture in the presence of large time gradients in the shower image detected by the camera. CHEC relies on dual-mirror optics to reduce the plate-scale and make use of 6 × 6 mm 2 pixels, leading to a low-cost ( ∼ 150 k€), compact (0.5 m × 0.5 m), and light ( ∼ 45 kg) camera with 2048 pixels providing a camera FoV of ∼ 9 degrees. The CHEC electronics are based on custom TARGET (TeV array readout with GSa/s sampling and event trigger) application-specific integrated circuits (ASICs) and field programmable gate arrays (FPGAs) sampling incoming signals at a gigasample per second, with flexible camera-level triggering within a single backplane FPGA. CHEC is designed to observe in the γ -ray energy range of 1–300 TeV, and at impact distances up to ∼ 500 m. To accommodate this and provide full flexibility for later data analysis, full waveforms with 96 samples for all 2048 pixels can be read out at rates up to ∼ 900 Hz. The first prototype, CHEC-M, based on multi-anode photomultipliers (MAPMs) as photosensors, was commissioned and characterised in the laboratory and during two measurement campaigns on a telescope structure at the Paris Observatory in Meudon. In this paper, the results and conclusions from the laboratory and on-site testing of CHEC-M are presented. They have provided essential input on the system design and on operational and data analysis procedures for a camera of this type. A second full-camera prototype based on Silicon photomultipliers (SiPMs), addressing the drawbacks of CHEC-M identified during the first prototype phase, has already been built and is currently being commissioned and tested in the laboratory.

The SuperTIGER (Super Trans-Iron Galactic Element Recorder) long-duration balloon instrument has measured the abundances of galactic cosmic-ray elements from _(10)Ne to _(40)Zr with high statistics and single element resolution and its measurements extend to about _(60)Nd. SuperTIGER is the first instrument to measure the abundance of every element from Z = 30 to 40 with significant statistics, recording more than 600 nuclei with atomic number Z > 30 in its first flight. Its measured nuclear charge resolution is excellent, with σ_Z = 0.16 c.u. at _(26)Fe. From 0.8 to 10 GeV/nucleon it also measures the energy spectra of the more abundant elements with 10 ≤ Z ≤ 30. SuperTIGER-1 launched from Williams Field, McMurdo Station, Antarctica, on December 8, 2012, flew for a record 55 days and over 2.5 revolutions around the continent, returned data on over 50 million heavy cosmic ray nuclei. The instrument has now been recovered from Antarctica and preparations are underway for its next flight. Instrument and flight details, methods of charge identification employed, preliminary results from the SuperTIGER-1 balloon flight, and a summary of the recovery will be presented. The SuperTIGER-1 measurements will be discussed in the context of their stringent tests of the OB association model for the origin of galactic cosmic rays. Finally, planned improvements to the SuperTIGER instrument and future flight plans will be described. Treatment of the data depends somewhat on Z and details of the data analysis and results in ranges 10 ≤ Z ≤ 29 and 30 ≤ Z ≤ 40 are given in other talks at this conference. SuperTIGER was developed by Washington University in St. Louis, NASA Goddard Space Flight Center, the California Institute of Technology, Jet Propulsion Laboratory, and the University of Minnesota.

The SuperTIGER (Trans-Iron Galactic Element Recorder) experiment was launched on a long-duration balloon flight from Williams Field, Antarctica, on December 8, 2012. SuperTIGER flew for a total of 55 days at a mean atmospheric depth of 4.4 g/cm^2. The instrument measured the abundances of galactic cosmic rays in the charge (Z) range Z ≥ 10 with excellent charge resolution, displaying well resolved individual element peaks for 10 ≤ Z ≤ 40. SuperTIGER collected ∼ 3.95 × 10^6 Iron nuclei, ∼ 7.1 times as many as detected by TIGER. We will present details of the data analysis techniques and the elemental abundances in the range 30 ≤ Z ≤ 40. The data presented contain more than 600 events in this charge range, with charge resolution at _(26)Fe of < 0.18 cu. Our measured abundances are generally consistent with those measured by TIGER and ACE. Our results confirm the earlier results from TIGER, supporting a model of cosmic-ray origin in OB associations, with preferential acceleration of refractory elements over volatile elements.

The quality of Cadmium Zinc Telluride (CZT) detectors is steadily improving. For state of the art detectors, readout noise is thus becoming an increasingly important factor for the overall energy resolution. In this contribution, we present measurements and calculations of the dark currents and capacitances of 0.5 cm-thick CZT detectors contacted with a monolithic cathode and 8x8 anode pixels on a surface of 2 cm x 2 cm. Using the NCI ASIC from Brookhaven National Laboratory as an example, we estimate the readout noise caused by the dark currents and capacitances. Furthermore, we discuss possible additional readout noise caused by pixel-pixel and pixel-cathode noise coupling., Proceedings of IEEE NSS-MIC October 2007 Hawaii

The Modified Horizontal Bridgman (MHB) process produces Cadmium Zinc Telluride (CZT) crystals with high yield and excellent homogeneity. Various groups,including our own, previously reported on the test of 2x2x0.5 cm3 MHB CZT detectors grown by the company Orbotech and read out with 8x8 pixels. In this contribution, we describe the optimization of the photolithographic process used for contacting the CZT detector with pixel contacts. The optimized process gives a high yield of good pixels down to pixel diameters/pitches of 50 microns. Furthermore, we discuss the performance of 0.5 cm and 0.75 cm thick detectors contacted with 64 and 225 pixel read out with the RENA-3 ASICs from the company NOVA R&D., 5 pages, 14 figures,Proceedings of NSS/MIC 2007 conference, October 2007, Hawaii

The SuperTIGER (Super Trans-Iron Galactic Element Recorder) instrument was developed to measure the abundances of galactic cosmic-ray elements from _(10)Ne to _(40)Zr with individual element resolution and the high statistics needed to test models of cosmic-ray origins. SuperTIGER also makes exploratory measurements of the abundances of elements with 40 < Z ≤ 60 and measures the energy spectra of the more abundant elements for Z ≤ 30 from about 0.8 to 10 GeV/nucleon. This instrument is an enlarged and higher resolution version of the earlier TIGER instrument. It was designed to provide the largest geometric acceptance possible and to reach as high an altitude as possible, flying on a standard long-duration 1.11 million m^3 balloon. SuperTIGER was launched from Williams Field, McMurdo Station, Antarctica, on 2012 December 8, and made about 2.7 revolutions around the South Pole in 55 days of flight, returning data on over 50 × 10^6 cosmic-ray nuclei with Z ≥ 10, including ∼1300 with Z >29 and ∼60 with Z >49. Here, we describe the instrument, the methods of charge identification employed, the SuperTIGER balloon flight, and the instrument performance.

The Schwarzschild-Couder Telescope (SCT) is a candidate technology for a medium-sized telescope within the Cherenkov Telescope Array, the next generation ground based observatory for very high energy gamma ray astronomy. The SCT uses a novel two-mirror design and is expected to yield improvements in field of view and image resolution compared to traditional Cherenkov telescopes based on single-mirror-dish optics. To match the improved optical resolution, challenging requirements of high channel count and density at low power consumption must be overcome by the camera. The prototype camera, currently commissioned and tested on the prototype SCT, has been developed based on millimeter scale SiPM pixels and a custom high density digitizer ASIC, TARGET, to provide 1600 pixels spanning a 2.7 degree field of view while being able to sample nanosecond photon pulses. It is mechanically designed to allow for an upgrade to 11,328 pixels covering a field of view of 8 degrees and demonstrating the full potential of the technology. The camera was installed on the telescope in 2018. We will present its design and performance including first light data., Comment: ICRC 2019 Proceeding