PixDD: a multi-pixel silicon drift detector for high-throughput spectral-timing studies

The Pixelated silicon Drift Detector (PixDD) is a two-dimensional multi-pixel X-ray sensor based on the technology of Silicon Drift Detectors, designed to solve the dead time and pile-up issues of photon-integrating imaging detectors. Read out by a two-dimensional self-triggering Application-Specific Integrated Circuit named RIGEL, to which the sensor is bump-bonded, it operates in the 0:5 — 15 keV energy range and is designed to achieve single-photon sensitivity and good spectroscopic capabilities even at room temperature or with mild cooling (< 150 eV resolution at 6 keV at 0 °C). The paper reports on the design and performance tests of the 128-pixel prototype of the fully integrated system

The sparse readout RIGEL Application Specific Integrated Circuit for Pixel Silicon Drift Detectors in soft X-ray imaging space applications

An Application Specific Integrated Circuit (ASIC), called RIGEL, designed for the sparse readout of a Silicon Pixel Drift Detector (PixDD) for space applications is presented. The low leakage current (less than 1 pA at +20 degrees C) and anode capacitance (less than 40 fF) of each pixel (300 mu m x 300 mu m) of the detector, combined with a low-noise electronics readout, allow to reach a high spectroscopic resolution performance even at room temperature. The RIGEL ASIC front-end architecture is composed by a 2-D matrix of 128 readout pixel cells (RPCs), arranged to host, in a 300 mu m-sided square area, a central octagonal pad (for the PixDD anode bump-bonding), and the full-analog processing chain, providing a full-shaped and stretched signal. In the chip periphery, the back-end electronics features 16 integrated 10-bits Wilkinson ADCs, the configuration register and a trigger management circuit. The characterization of a single RPC has been carried out whose features are: eight selectable peaking times from 0.5 mu s to 5 mu s, an input charge range equivalent to 30 keV, and a power consumption of less than 550 mu W per channel. The RPC has been tested also with a 4x4 prototype PixDD and 167 eV Full Width at Half Maximum (FWHM) at the 5.9 keV line of Fe-55 at 0 degrees C and 1.8 mu s of peaking time has been measured

ORION, a Multichip Readout Electronics for Satellite Wide Energy Range X-/γ-Ray Imaging Spectroscopy: Design and Characterization of the Analog Section

The ORION chipset, a full-custom multichip readout and processing electronics for the X- γ -ray imaging spectrometer (XGIS) on-board the transient high-energy sky and early universe surveyor (THESEUS) space mission, is presented. The XGIS detection plane is arranged in a matrix of 10 × 10 detection modules, each one composed of 64 CsI(Tl) scintillation bars (4.5 mm × 4.5 mm × 30 mm) optically coupled at the top and bottom ends to two 8 × 8 monolithic silicon drift detector (SDD) matrices. The top SDD, exposed to the X-ray entrance window, performs the double function of low-energy X-ray detection as well as scintillator’s readout, together with the bottom SDD, providing detection and spectroscopic energy range from 2 keV up to 20 MeV. The need to achieve a high-energy resolution, as well as a high sensitive area on the detection plane, led to the development of a chipset organized to have a minimum-area analog readout chip placed in close proximity of the SDD (ORION-FE) and a mixed-signal back-end (ORION-BE) placed a few centimeters further on the back-end board for the additional signal processing and digitization. The multichip readout electronics integrates two dedicated analog processors for low-energy photons up to 30 keV (X-processor) and high-energy photons up to 5 MeV ( γ -processor), allowing a spectroscopy-grade resolution in the 4 decades energy band (2 keV–20 MeV) of the XGIS, with a simulated power consumption of 1.55 mW/pixel. The ORION prototype was bonded to two ~25 mm^2 SDDs, and extensively characterized in terms of pulse shaping, pulse discrimination, and stretching functionality, as well as linearity, dynamic range, and spectroscopic resolution. An optimum equivalent noise charge (ENC) at −20 °C of 24.3 el. r.m.s. on the X-channel [212 eV full-width at half-maximum (FWHM) on Si], and 39.6 el. r.m.s. on the γ -channel [3.7 keV FWHM on CsI(Tl)] has been recorded

PixDD: a multi-pixel silicon drift detector for high-throughput spectral-timing studies

The Pixelated silicon Drift Detector (PixDD) is a two-dimensional multi-pixel X-ray sensor based on the technology of Silicon Drift Detectors, designed to solve the dead time and pile-up issues of photon-integrating imaging detectors. Read out by a two-dimensional self-triggering Application-Speci c Integrated Circuit named RIGEL, to which the sensor is bump-bonded, it operates in the 0:5 - 15 keV energy range and is designed to achieve single-photon sensitivity and good spectroscopic capabilities even at room temperature or with mild cooling (&lt; 150 eV resolution at 6 keV at 0 °C). The paper reports on the design and performance tests of the 128-pixel prototype of the fully integrated system

Study of radiation-induced effects on the RIGEL ASIC

This paper assesses the response to radiation effects of the RIGEL, the Application Specific Integrated Circuit developed within the framework of the PixDD project, to be coupled with a multi-pixel sensor based on Silicon Drift Detectors for operation at the focal plane of X-ray optics on board space-borne astronomy missions. The campaign was conducted at the heavy ion beam line of the Radiation Effects Facility of the University of Jyväskylä (Finland): both the response to Single Event Effects (latch-ups and bit ips) and to Total Ionising Dose was evaluated. Experimental data were combined with simulations of the in-orbit environment for two scenarios: an equatorial and a Sun-synchronous orbit. The study demonstrated that the device can be safely operated on an equatorial orbit without any dedicated circuitry to mitigate Single Event Effects, although this precaution is instead advisable in the case of a Sun-synchronous orbit. Spectroscopic degradation resulting from Total Ionising Dose stays below 10% up to 34 krad, a manageable value for both orbital configurations

Design, integration, and test of the scientific payloads on-board the HERMES constellation and the SpIRIT mission

HERMES (high energy rapid modular ensemble of satellites) is a space-borne mission based on a constellation of nano-satellites flying in a low-Earth orbit (LEO). The six 3U CubeSat buses host new miniaturized instruments hosting a hybrid silicon drift detector/GAGG:Ce scintillator photodetector system sensitive to x-rays and gamma-rays. HERMES will probe the temporal emission of bright high-energy transients such as gamma-ray bursts (GRBs), ensuring a fast transient localization (with arcmin-level accuracy) in a field of view of several steradians exploiting the triangulation technique. With a foreseen launch date in late 2023, HERMES transient monitoring represents a keystone capability to complement the next generation of gravitational wave experiments. Moreover, the HERMES constellation will operate in conjunction with the space industry responsive intelligent thermal (SpIRIT) 6U CubeSat, to be launched in early 2023. SpIRIT is an Australian-Italian mission for high-energy astrophysics that will carry in a sun-synchronous orbit (SSO) an actively cooled HERMES detector system payload. On behalf of the HERMES collaboration, in this paper we will illustrate the HERMES and SpIRIT payload design, integration and tests, highlighting the technical solutions adopted to allow a wide-energy-band and sensitive x-ray and gamma-ray detector to be accommodated in a 1U CubeSat volume