F. Ficorella

Silicon Drift Detectors for Readout of Scintillators in Gamma-Ray Spectroscopy

In this work, we report on a new development of Silicon Drift Detectors (SDDs) for gamma-ray spectroscopy with space science applications. The research is supported by the European Space Agency through the Technology Research Programme (TRP). The final goal of the development is the realization of monolithic arrays of SDDs which will be assembled to readout large (2” and 3”) LaBr3(Ce) scintillators. We present here the results of the development of a single SDD prototype, with 8 × 8 mm2 active area, produced at Fondazione Bruno Kessler (FBK) semiconductor laboratories. We discuss the design issues related to the specific use of this device as a photo-detector for scintillators. Then, we focus on the read-out electronics. Since this SDD does not include a front-end transistor on the silicon chip, we have adopted a CMOS charge preamplifier (CUBE) recently developed at Politecnico di Milano. This preamplifier has allowed the achievement of state-of-the-art noise performance using a SDD technology process without the integration of the FET (Field Effect Transistor) on the detector chip. A quantum efficiency of about 80% has been measured for the SDD at the emission wavelength band of LaBr3 (360-380 nm). First experimental measurements consisting of direct 55 Fe irradiation of the SDD without scintillator, have demonstrated energy resolution of 140 eV and 129 eV at -20°C and -43°C respectively. By coupling the SDD with a LaBr3(Ce) scintillator (9 mm diameter), we have measured energy resolution of 5.6% FWHM and 2.6% FWHM at 122 keV and 662 keV respectively.

Silicon Drift Detectors and CUBE Preamplifiers for High-Resolution X-ray Spectroscopy

In this work we present the results of the experimental characterization of Silicon Drift Detectors (SDDs) readout by CUBE preamplifiers for X-ray spectroscopy measurements. One specific goal of the work was to characterize SDDs of different sizes cooled at low temperature in view of their use in the upgrade of the SIDDHARTA nuclear physics experiment. Beside the target application, the results of this work are also of interest for a more extended use of the SDDs in other X-ray spectroscopy applications. The SDDs have been designed as single units with square shape of different areas, 64 mm2 (8 mm × 8 mm) and 144 mm2 (12 mm × 12 mm), and also as monolithic array of 3×3 elements of the 8 mm × 8 mm unit (total area 26 mm × 26 mm). The read-out of the SDDs is based on a CMOS (Complementary Metal Oxide Semiconductor) preamplifier (CUBE) both for the single unit and for the 3×3 array. For the readout of the array, an Application Specific Integrated Circuit (ASIC) has been used. An energy resolution better than 124 eV at the Mn-Kα line has been measured with a 64 mm2 SDD cooled at the temperature of 50 K. The energy resolution remains good (<;130 eV) also at short shaping time (250 ns) thanks to the noise feature of the CUBE preamplifier. Results of measurements on SDDs of different format and also on arrays of SDDs are presented in this work.

Recent proton and Co60 radiation test data from a newly developed European optocoupler source for space application

The permanent degradation introduced in the main electrical parameters of a newly developed European optocoupler type is described, as a function of proton fluences and Co-60 total ionizing dose. Optois devices assembled in Leadless Chip Carrier packages, coded OIER10 are being developed in the framework of an ECI project for ESA, aimed at the ESCC evaluation of Optoi optocouplers. The first analyses of the recent irradiation results show a good behavior of the parts under proton and gamma irradiation.

New developments of SDD-based X-ray detectors for the Siddharta-2 experiment

In this work we present new developments of Silicon Drift Detectors (SDDs) of different sizes in view of their use in future Siddharta-2 experiments. The SIDDHARTA experiment used X-ray spectroscopy of the kaonic atoms to determine the transition yields and the strong interaction induced shift and width at the lowest experimentally accessible level. In this work we report about the SDDs development for the apparatus upgrade, with particular emphasis of X-ray measurements at cryogenic temperatures. The SDDs presented are designed as single unit with square shaped of different areas 64 mm2 (8 mm × 8 mm) or 144 mm2 (12 mm × 12 mm) and also as monolithic array of 9 elements (8 mm × 8 mm each, total area 26 mm × 26 mm) in a 3×3 format. The read-out of the SDDs is based on a CMOS preamplifier (CUBE) both for the single unit both for the 3×3 array. The array required in addition the use of an Application Specific Integrated Circuit (ASIC) and of a custom Data Acquisition System for the acquisition of all the units. The CMOS technology is intrinsically more robust at lower temperatures than the more conventional JFET transistor used in SDDs readout and it allows the use of these devices at cryogenic temperatures. For instance an energy resolution lower than 125 eV at the MnKa line has been obtained with a 64 mm2 at the temperature of 50 K and shaping time of 2 μs.

The large area detector onboard the eXTP mission

The eXTP (enhanced X-ray Timing and Polarimetry) mission is a major project of the Chinese Academy of Sciences (CAS) and China National Space Administration (CNSA) currently performing an extended phase A study and proposed for a launch by 2025 in a low-earth orbit. The eXTP scientific payload envisages a suite of instruments (Spectroscopy Focusing Array, Polarimetry Focusing Array, Large Area Detector and Wide Field Monitor) offering unprecedented simultaneous wide-band X-ray spectral, timing and polarimetry sensitivity. A large European consortium is contributing to the eXTP study and it is expected to provide key hardware elements, including a Large Area Detector (LAD). The LAD instrument for eXTP is based on the design originally proposed for the LOFT mission within the ESA context. The eXTP/LAD envisages a deployed 3.4 m2 effective area in the 2-30 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors - offering a spectral resolution of up to 200 eV FWHM at 6 keV - and of capillary plate collimators - limiting the field of view to about 1 degree. In this paper we provide an overview of the LAD instrument design, including new elements with respect to the earlier LOFT configuration.

Development of Ultra-Fast Silicon Detectors for 4D tracking

In this contribution we review the progress towards the development of a novel type of silicon detectors suited for tracking with a picosecond timing resolution, the so called Ultra-Fast Silicon Detectors. The goal is to create a new family of particle detectors merging excellent position and timing resolution with GHz counting capabilities, very low material budget, radiation resistance, fine granularity, low power, insensitivity to magnetic field, and affordability. We aim to achieve concurrent precisions of ~ 10 ps and ~ 10 μm with a 50 μm thick sensor. Ultra-Fast Silicon Detectors are based on the concept of Low-Gain Avalanche Detectors, which are silicon detectors with an internal multiplication mechanism so that they generate a signal which is factor ~10 larger than standard silicon detectors. The basic design of UFSD consists of a thin silicon sensor with moderate internal gain and pixelated electrodes coupled to full custom VLSI chip. An overview of test beam data on time resolution and the impact on this measurement of radiation doses at the level of those expected at HL-LHC is presented. First I-V and C-V measurements on a new FBK sensor production of UFSD, 50 μm thick, with B and Ga, activated at two diffusion temperatures, with and without C co-implantation (in Low and High concentrations), and with different effective doping concentrations in the Gain layer, are shown. Perspectives on current use of UFSD in HEP experiments (UFSD detectors have been installed in the CMS-TOTEM Precision Protons Spectrometer for the forward physics tracking, and are currently taking data) and proposed applications for a MIP timing layer in the HL-LHC upgrade are briefly discussed.

Development and ESCC evaluation of an European optocoupler for space applications

This paper presents Optoi’s Optocouplers, being developed in the frame of ESA’s European Component Initiative (Phase 2). Their design and main test results are reported, together with the plan of future activities, including the Evaluation Test Plan and radiation tests.

New development of Silicon Drift Detectors for gamma-ray spectroscopy

In this work, we report on a new development of Silicon Drift Detectors (SDDs) for gamma-ray spectroscopy for astronomy applications, within a research project supported by the European Space Agency. The final goal of the development is the realization of monolithic arrays of SDDs which will be assembled to readout large (2″×2″ and 3″×3″) LaBr<inf>3</inf> scintillators. We report on the development of a new single SDD prototype, with 8×8 mm² active area, produced at FBK semiconductor laboratories. For the readout of the SDD signals,we have adopted a CMOS charge preamplifier (CUBE) recently developed at Politecnico di Milano. This preamplifier has allowed to achieve state-of-the-art noise performance using a relatively standard SDD technology process. A quantum efficiency of about 80% has been measured on the SDD at the emission wavelengths of LaBr<inf>3</inf> (360–380 nm). In first experimental measurements irradiating the SDD, without scintillator, with a ⁵⁵Fe source we achieved an energy resolution of 140eV and 129eV, respectively, at −20°C and −43°C. By coupling the SDD with a LaBr<inf>3</inf> scintillator (9mm diameter), we have measured an energy resolution of 5.6% FWHM and 2.6% FWHM respectively at 122keV and 662keV.

The wide field monitor onboard the eXTP mission

The eXTP (enhanced X-ray Timing and Polarimetry) mission is a major project of the Chinese Academy of Sciences (CAS) and China National Space Administration (CNSA) currently performing an extended phase A study and proposed for a launch by 2025 in a low-earth orbit. The eXTP scientific payload envisages a suite of instruments (Spectroscopy Focusing Array, Polarimetry Focusing Array, Large Area Detector and Wide Field Monitor) offering unprecedented simultaneous wide-band X-ray timing and polarimetry sensitivity. A large European consortium is contributing to the eXTP study and it is expected to provide key hardware elements, including a Wide Field Monitor (WFM). The WFM instrument for eXTP is based on the design originally proposed for the LOFT mission within the ESA context. The eXTP/WFM envisages a wide field X-ray monitor system in the 2-50 keV energy range, achieved through the technology of the large-area Silicon Drift Detectors. The WFM will consist of 3 pairs of coded mask cameras with a total combined Field of View (FoV) of 90×180 degrees at zero response and a source localization accuracy of ~1 arcmin. In this paper we provide an overview of the WFM instrument design, including new elements with respect to the earlier LOFT configuration, and anticipated performance.

Double-sided strip sensors for the Limadou-CSES project

Production of 71 AC-coupled double-sided silicon microstrip sensors, designed to equip the two layers of the High Energy Particle Detector (HEPD) detector in the Limadou-CSES (China Seismo-Electromagnetic Satellite) project, has been recently completed at FBK. The sensors, fabricated on 150 mm silicon wafers, have an overall size of 10.96 cm