F. Pinsard

IDeF-X ECLAIRs: A CMOS ASIC for the Readout of CdTe and CdZnTe Detectors for High Resolution Spectroscopy

The very last member of the IDeF-X ASIC family is presented: IDeF-X ECLAIRs is a 32-channel front end ASIC designed for the readout of Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) Detectors. Thanks to its noise performance (Equivalent Noise Charge floor of 33 e- rms) and to its radiation hardened design (Single Event Latchup Linear Energy Transfer threshold of 56 MeV.cm2.mg-1), the chip is well suited for soft X-rays energy discrimination and high energy resolution, ldquospace proof,rdquo hard X-ray spectroscopy. We measured an energy low threshold of less than 4 keV with a 10 pF input capacitor and a minimal reachable sensitivity of the Equivalent Noise Charge (ENC) to input capacitance of less than 7 e-/pF obtained with a 6 mus peak time. IDeF-X ECLAIRs will be used for the readout of 6400 CdTe Schottky monopixel detectors of the 2D coded mask imaging telescope ECLAIRs aboard the SVOM satellite. IDeF-X ECLAIRs (or IDeF-X V2) has also been designed for the readout of a pixelated CdTe detector in the miniature spectro-imager prototype Caliste 256 that is currently foreseen for the high energy detector module of the Simbol-X mission.

CALISTE 64, an innovative CdTe hard X-Ray micro-camera

In the frame of the hard X-ray simbol-X observatory, a joint CNES-ASI space mission to be flown in 2013, a prototype of miniature camera equipped with 64 pixels has been designed. The device, called CALISTE 64, is a spectro- imager with high resolution event time-tagging capability. CALISTE 64 integrates a CdTe semiconductor detector with segmented electrode and its front-end electronics made of 64 independent analogue readout channels. This 10times10times18 mm3 camera, able to detect photons in the range from 2 keV up to 250 keV, is an elementary detection unit juxtaposable on its four sides. Consequently, large detector array can be made assembling a mosaic of CALISTE 64 units. Electronics readout module is achieved by stacking four IDeF-X V1.1 ASICs in a 3D-module, perpendicular to the detection plane. We achieved good noise performances, with an equivalent noise charge better than 60 electrons rms in average. We choose CdTe detectors equipped with aluminum Schottky barrier contacts because of their very low dark current and excellent spectroscopic performances. The first integrated CALISTE 64 camera was realized and tested. The device operates properly and all the 64 pixels show good spectra. When the crystal is cooled down to -10degC and biased at -400 V, the resulting sum spectrum shows a spectral resolution of 697 eV FWHM at 13.9 keV and 808 eV FWHM at 59.54 keV. This paper presents the CALISTE 64 design and preliminary performance test results.

IDeF-X HD: A low power multi-gain CMOS ASIC for the readout of Cd(Zn)Te detectors

SINCE few years, our group is developing a family of ASICs for space applications, named IDeF-X for Imaging Detector Front-end [l]-[4]. IDeF-X HD is the new member of the IDeF-X family. It has been optimized for the readout of 16 × 16 pixels CdTe or CdZnTe pixelated detectors to build a new low power Caliste 256 module [5]. This micro gamma-camera will be the elementary unit of the MAC SI (Modular Assembly of Caliste Spectro Imager) camera: A 2048-pixels 8 cm2 gamma camera designed with 8 identical Caliste modules.

Caliste 64, an Innovative CdTe Hard X-Ray Micro-Camera

A prototype 64 pixel miniature camera has been designed and tested for the Simbol-X hard X-ray observatory to be flown on the joint CNES-ASI space mission in 2014. This device is called Caliste 64. It is a high performance spectro-imager with event time-tagging capability, able to detect photons between 2 keV and 250 keV. Caliste 64 is the assembly of a 1 or 2 mm thick CdTe detector mounted on top of a readout module. CdTe detectors equipped with aluminum Schottky barrier contacts are used because of their very low dark current and excellent spectroscopic performance. Front-end electronics is a stack of four IDeF-X Vl.l ASICs, arranged perpendicular to the detection plane, to read out each pixel independently. The whole camera fits in a 10 times 10 times 20 mm3 volume and is juxtaposable on its four sides. This allows the device to be used as an elementary unit in a larger array of Caliste 64 cameras. Noise performance resulted in an ENC better than 60 electrons rms in average. The first prototype camera is tested at -10degC with a bias of -400 V. The spectrum summed across the 64 pixels results in a resolution of 697 eV FWHM at 13.9 keV and 808 eV FWHM at 59.54 keV.

SIMBOL-X: a formation flying mission for hard-x-ray astrophysics

SIMBOL-X is a hard X-ray mission, operating in the ~ 0.5-70 keV range, which is proposed by a consortium of European laboratories in response to the 2004 call for ideas of CNES for a scientific mission to be flown on a formation flying demonstrator. Relying on two spacecrafts in a formation flying configuration, SIMBOL-X uses for the first time a ~ 30 m focal length X-ray mirror to focus X-rays with energy above 10 keV, resulting in a two orders of magnitude improvement in angular resolution and sensitivity in the hard X-ray range with respect to non focusing techniques. The SIMBOL-X revolutionary instrumental capabilities will allow to elucidate outstanding questions in high energy astrophysics, related in particular to the physics of accretion onto compact objects, to the acceleration of particles to the highest energies, and to the nature of the Cosmic X-Ray background. The mission, which has gone through a thorough assessment study performed by CNES, is expected to start a competitive phase A in autumn 2005, leading to a flight decision at the end of 2006, for a launch in 2012. The mission science objectives, the current status of the instrumentation and mission design, as well as potential trade-offs are presented in this paper.

The European contribution to the SPICA mission

The Japanese led Space Infrared telescope for Cosmology and Astrophysics (SPICA) will observe the universe over the 5 to 210 micron band with unprecedented sensitivity owing to its cold (~5 K) 3.5m telescope. The scientific case for a European involvement in the SPICA mission has been accepted by the ESA advisory structure and a European contribution to SPICA is undergoing an assessment study as a Mission of Opportunity within the ESA Cosmic Vision 1015-2015 science mission programme. In this paper we describe the elements that are being studied for provision by Europe for the SPICA mission. These entail ESA directly providing the cryogenic telescope and ground segment support and a consortium of European insitutes providing a Far Infrared focal plane instrument. In this paper we describe the status of the ESA study and the design status of the FIR focal plane instrument.

Caliste HD: A new fine pitch Cd(Zn)Te imaging spectrometer from 2 keV up to 1 MeV

Caliste HD is the last member of the Caliste family of Cd(Zn)Te micro-cameras for space applications. This hybrid component is made of the assembly of one 16 × 16 pixel Cd(Zn)Te detector and eight analog front-end ASIC named IDeF-X HD equipped with 32 spectroscopic channels. The pixels are 625 µm pitch and are surrounded by a 20 µm wide guard ring. The new generation of ASIC has the advantage of having a power consumption 4 times lower as the previous version (0.2 W for the full device) and offers the possibility to extend the dynamic range from 250 keV to 1 MeV. The technology is fully compliant with operation in space (tolerant to radiation, thermal and mechanical constraints). This paper presents the preliminary spectroscopic results obtained with the samples produced so far. At −16°C the sum spectrum built with all single events of the 1 mm-thick Al Schottky detector show an energy resolution of 0.82 keV FWHM at 14 keV and 0.92 keV FWHM at 60 keV. A good uniformity in gain and in noise is measured over the 256 pixels; the low level-threshold is lower than 2 keV for all pixels.

Micro hard-X ray camera: From Caliste 64 to Caliste 256

Caliste project aims at hybridizing 1 cm2 Cd(Zn)Te detectors with low noise front-end electronics, in a single component standing in a 1 × 1 × 2 cm3 volume. The micro-camera is a spectro-imager for X and gamma rays detection, with time-tagging capability. Hybridization consists in stacking full custom ASICs perpendicular to the detection surface. The first prototype Caliste 64 integrates a detector of 8 × 8 pixels of 1 mm pitch. Fabrication and characterizations of nine cameras samples validate the design and the hybridization concept. Spectroscopic tests result in a mean energy resolution of ∼0.7 keV FWHM at 14 keV and ∼0.85 keV FWHM at 60 keV with 1 mm-thick Al Schottky CdTe detectors biased at −400V and cooled down to −15°C. The new prototype called Caliste 256 integrates 16 × 16 pixels of 580 8m pitch in the same volume as Caliste 64. Electrical tests with the first sample fabricated without detector result in a mean equivalent noise charge of 64 el. rms (9.6 μs, no leakage current). Caliste devices are 4-side buttable and can be used as elementary detection units of a large hard X-ray focal plane, as for the 64 cm2 high energy detector of the Simbol-X astronomical space mission.

The Herschel-SPIRE photometer data processing pipeline

We describe the on-board electronics chain and the on-ground data processing pipeline that will operate on data from the Herschel-SPIRE photometer to produce calibrated astronomical products. Data from the three photometer arrays will be conditioned and digitised by on-board electronics and sent to the ground with no further on-board data processing. On the ground, the data pipeline will process the data from point source, jiggle-map, and scan-map observations in a fully automatic manner, producing measured flux densities (for point source observations) or maps. It includes calculation of the bolometer voltages from the raw telemetry, glitch removal, and corrections for various effects including time constants associated with the detectors and electronics, electrical and optical crosstalk, detector temperature drifts, flatfielding, and non-linear response of the bolometers to strong sources. Flux density calibration will be with respect to standard astronomical sources with the planets Uranus and Neptune being adopted as the baseline primary standards. The pipeline will compute estimated values of in-beam flux density for a standard flat νS(ν) source spectrum.

The French payload on-board the SVOM French-Chinese mission

The SVOM (Space-based multi-band astronomical Variable Objects Monitor) French-Chinese mission is dedicated to the detection, localization and study of Gamma Ray Bursts (GRBs) and other high-energy transient phenomena. We first present the major principles of the SVOM system including the alert system providing near-real-time GRB localizations to large ground-based telescopes. Then the paper describes the definition of the SVOM payload and more particularly the French payload composed of the ECLAIRs instrument, dedicated to GRB detection and positioning, and the MXT instrument, dedicated to GRB followup observation in soft X-ray band.