118602523
Field Camera Unit for WSO-UV: Phase A Study Report
World Space Observatory UltraViolet (WSO-UV) is a multipurpose space observatory, made by a 170 cm aperture telescope, capable of UV high-resolution spectroscopy, long slit low-resolution spectroscopy, and deep UV and optical imaging. With a nominal mission life time of 5 years, and a planned extension to 10 years, from a geosynchronous orbit with an inclination of 51.8 degrees, WSO-UV will provide observations of exceptional importance for the study of many unsolved astrophysical problems. WSO-UV is implemented in the framework of a collaboration between Russia (chair), China, Germany, Italy, Spain, and Ukraine. This book illustrates the results of the feasibility study for the Field Camera Unit (FCU), a multi-spectral radial instrument on the focal plane of WSO-UV. The book provides an overview of the key science topics that are drivers to the participation of the Italian astronomical community in the WSO-UV project. The science drivers here illustrated have been used to define the technical requirements for the conceptual and architectural design of the Field Camera Unit (FCU) focal plane instrument. In Chapter I we show that WSO-UV will give a significant contribution to solve the key astronomical problems individuated by the ASTRONET consortium, and which are driving the European Space Agency Cosmic Vision program. Chapter II elucidates the scientific requirements for WSO-UV FCU instrument, discussed in Chapter I, which are translated in a list of verifiable top level requirements usable to make the conceptual design of the FCU instrument. Chapter III is dedicated to the Field Camera Unit opto-mechanical design, its detectors and electronics subsystems. Finally, Chapter IV outlines the AIV and GSE plans and activities for the FCU instrument.
21005600
Study of Single Event transients on the VELA ASIC, x-ray detectors FEE for new generation astronomical instruments
It is well known that the use of electronics components in space exposes them to ionizing radiation, which can damage the devices. A careful characterization of the sensitivity to radiation-induced damages is thus of capital importance for the critical devices. VELA (VLSI Electronic for Astronomy) is an ASIC developed at the Politecnico of Milano in collaboration with Max-Planck-Institut Semiconductor Laboratory, in 0.35 µm AMS CMOS technology, which implements the readout front-end electronics for an innovative x-ray detector, the DEPMOS-based APS, Active Pixel Sensor. This sensor is capable of providing an excellent energy resolution even at very high speed readout. The absence of the charge transfer mechanism, makes APS sensors very attractive for harsh radiation space environments. The behavior of the front-end electronics under irradiation is then a critical issue. We present a study of the Single Event Effects induced by heavy ions in VELA, in view of a possible utilization in new generation satellites for X-ray astronomy. The tests have been carried out at the SIRAD facility of the Laboratori Nazionali INFN di Legnaro. In this paper we describe the measurements and the experimental setup, designed and realized ad hoc to monitor Single Event Latch-up (SEL) and Single Event Upset (SEU).
118604795
The Soft X-ray Imager on board EXIST
The Soft X-ray Imager (SXI) is one of the three instruments on board EXIST, a multi-wavelength observatory in charge of performing a global survey of the sky in hard X-rays searching for Super-massive Black Holes (Grindlay & Natalucci, these Proceedings). One of the primary objectives of EXIST is also to study with unprecedented sensitivity the most unknown high energy sources in the Universe, like high redshift GRBs, which will be pointed promptly by the Spacecraft by autonomous trigger based on hard X-ray localization on board. The presence of a soft X-ray telescope with an effective area of about 950cm2 in the energy band 0.2-3 keV and extended response up to 10 keV will allow to make broadband studies from 0.1 to 600 keV. In particular, investigations of the spectra components and states of AGNs and monitoring of variability of sources, study of the prompt and afterglow emission of GRBs since the early phases, which will help to constrain the emission models and finally, help the identification of sources in the EXIST hard X-ray survey and the characterization of the transient events detected. SXI will also perform surveys: a scanning survey with sky coverage 2pi and a limiting flux of 5x10^(-14) cgs plus other serendipitous.
109311982
Pixel read-out architectures for the NA62 gigatracker
Beam particles in NA62 experiment are measured with a Si-pixel sensor having a size of 300 μm x 300 μm and a time resolution of 150 ps (rms). To meet the timing requirement an adequate strategy to compensate the discriminator time-walk must be implemented and an R&D effort investigating two different options is ongoing. In this presentation we describe the two different approaches. One is based on the use of a constant-fraction discriminator followed by an on-pixel TDC. The other one is based on the use of a Time-over-Threshold circuit followed by a TDC shared by a group of pixels. The global architectures of both the front-end ASIC will be discussed. I. THE GIGATRACKER SYSTEM The aim of the proposed NA62 experiment at the CERN SPS is to study the very rare decay of the charged K meson into a pion and neutrino-antineutrino pair. One of the key components of NA62 will be the GigaTracker, which consists of three matrices of Si-pixel stations, each covering a sensitive area of 60 mm x 27 mm. Each pixel is 300 μm x 300 μm [1]. The GigaTracker is designed to measure the beam particle trajectory with a space resolution of 100 μm (rms) and a timing accuracy of 150 ps (rms). In order to reconstruct the momentum of the beam particles a system of four dipoles, A1...A4 in Fig.1, provides the momentum selection followed by the beam recombination. The timing resolution of 150 ps (rms) is an unusual requirement for a traditional pixel detector and none of the existing systems has such a capability. Other challenging aspects are due to the high radiation operational environment and the very low material budget restraint (0.5% X0 per station, sensor thickness 200 μm, read-out chip thickness 150 μm). Figure 1: GigaTracker system Each silicon sensor will be read-out by 10 front-end ASICs, with 45x40 read-out cells each. The 10 read-out chips will be bump-bonded to the pixels, so only one side of the chip will be used for external connections (wire bonding pads in Fig. 2). Figure 2: Sensor and read-out chips The particle rate, which is higher in the central part of the sensor, is estimated to be ~1.5 MHz/mm maximum, which corresponds to 130 MHz per chip and 140 kHz per
56367858
EXPERIMENTAL STUDY OF CRYSTAL CHANNELING AT CERN-SPS FOR BEAM-HALO CLEANING
An efficient and robust collimation system is mandatory for any superconducting hadron collider, in particular for the LHC, which will store a beam of unprecedented high intensity and energy. The usage of highly efficient and short primary bent-crystal collimators might be a possibility for reaching nominal and ultimate LHC intensity. Over the last years, groups in Italy (Ferrara) and Russia (St. Petersburg) have developed crystal production methods, that considerably improve the crystal quality. These developments led, in turn, to a surprising increase in the channeling efficiency and to the recent observation of the “volume reflection” mechanism. The aim of the proposed experiment is the setup of a beam test facility, directing primary protons from the SPS onto a bent silicon crystal, and the quantitative study of single-pass efficiency for all involved processes. Final goal will be the extrapolation of important information on the feasibility of a crystal collimator for halo cleaning in the LHC. The experiment will be performed in the H8 beamline at the CERN SPS where a beam with very small divergence can be provided thus representing a unique facility for tests and characterizationof crystals to be used forparticle channeling studies.
108747990
The Gigatracker: An ultra-fast and low-mass silicon pixel detector for the NA62 experiment
The Gigatracker is a hybrid silicon pixel detector developed to track the highly intense NA62 hadron beam with a time resolution of 150 ps (rms). The beam spectrometer of the experiment is composed of three Gigatracker stations installed in vacuum in order to precisely measure momentum, time and direction of every traversing particle. Precise tracking demands a very low mass of the detector assembly (o0:5% X0 per station) in order to limit multiple scattering and beam hadronic interactions. The high rate and especially the high timing precision requirements are very demanding: two RD options are ongoing and the corresponding prototype read-out chips have been recently designed and produced in 0:13 mm CMOS technology. One solution makes use of a constant fraction discriminator and on-pixel analogue-based time-to-digital-converter (TDC); the other comprises a delay-locked loop based TDC placed at the end of each pixel column and a time-over-threshold discriminator with time- walk correction technique. The current status of the RD program is overviewed and results from the prototype read-out chips test are presented.
109328792
READOUT ELECTRONICS OF THE NA62 GIGATRACKER SYSTEM
A crucial detector of the NA62 experiment is the beam spectrometer named Gigatracker. It consists of three stations of hybrid silicon pixels sensors with 150 ps (rms) of time resolution and 100 μm (rms) of space resolution. In addition the system operates under a high radiation environment and a high density of particles (up to 1.5 MHz/mm in the centre and 0.8 1 GHz in total). To meet these requirements the readout electronics must compensate the discriminators time-walk and the dead time should be below 1%. In order to evaluate the best solution, two readout chips have been developed. One is based on the constant-fraction discriminator technique and the other one is based on the use of a time-over-threshold circuit. The global architectures of both the front-end ASIC will be discussed.