X. De La Broise

Radiation qualification of the front-end electronics for the readout of the ATLAS liquid argon calorimeters

The ATLAS detector has been built to study the reactions produced by the Large Hadron Collider (LHC). ATLAS includes a system of liquid argon calorimeters for energy measurements. The electronics for amplifying, shaping, sampling, pipelining, and digitizing the calorimeter signals is implemented on a set of front-end electronic boards. The front-end boards are installed in crates mounted between the calorimeters, where they will be subjected to significant levels of radiation during LHC operation. As a result, all components used on the front-end boards had to be subjected to an extensive set of radiation qualification tests. This paper describes radiation-tolerant designs, radiation testing, and radiation qualification of the front-end readout system for the ATLAS liquid argon calorimeters.

Large bulk-micromegas detectors for TPC applications in HEP

Bulk-MicroMegas detectors are based on a novel technology which is of particular interest for large area Micro Pattern Gas Detectors (MPGD). Their manufacturing process combines detector construction simplicity and robustness, allowing large sensitive areas to be produced at low cost. Such devices provide very good gas gain uniformity and detection coverage with small dead spaces. They are ideally suited in HEP applications where large volume tracking detectors with low material budget are required. This is the case, for instance, of the T2K neutrino experiment in Japan, in which large Time Proportional Chamber (TPC) devices will be used. Bulk- MicroMegas detectors are also being considered for the future Linear Collider Detector. We present in this paper the recent developments and performance of bulk-MicroMegas detectors for the T2K TPC.

The development of X-ray bolometers based on SOI technology for astronomy

Several successful development programs have been conducted on Infra-Red bolometer arrays at the French Atomic Energy Commission (CEA-LETI Grenoble), in collaboration with the CEA-Sap (Saclay); taking advantage of this background, we are now developing an X-ray spectro-imaging camera for next generation space astronomy missions, using silicon technology. We have developed monolithic silicon micro-calorimeters based on implanted thermistors. These micro-calorimeter arrays will be used for future space missions. A 8×8 array prototype consisting of a grid of 64 suspended pixels on SOI (Silicon On Insulator) has been created. Each pixel of this array detector is made of a tantalum (Ta) absorber and is bonded, by means of an indium bump hybridization process, to a silicon thermistor. The absorber array is bound to the thermistor array in a collective process step. The fabrication process of our detector involves a combination of standard silicon technologies such as Si bulk micromachining techniques, based on deposition, photolithography and plasma etching steps. Finally, we present the results of measurements performed on the different building elements and processes that are required to create a detector array up to 32*32 pixels in size.

AFTER, the front end ASIC of the T2K Time Projection Chambers

The T2K (Tokai-to-Kamioka) experiment is a long baseline neutrino oscillation experiment in Japan. A near detector, located at 280m of the production target, is used to characterize the beam. One of its key elements is a tracker, made of three Time Projection Chambers (TPC) read by Micromegas endplates. A new readout system has been developed to collect, amplify, condition and acquire the data produced by the 124,000 detector channels of these detectors. The front-end element of this system is a a new 72-channel application specific integrated circuit. Each channel includes a low noise charge preamplifier, a pole zero compensation stage, a second order Sallen-Key low pass filter and a 511-cell Switched Capacitor Array. This electronics offers a large flexibility in sampling frequency, shaping time, gain, while taking advantage of the low physics events rate of 0.3 Hz. We detail the design and the performance of this ASIC and report on the deployment of the frond-end electronics on-site.

Large high impedance silicon μ-calorimeters for x-rays camera: status and perspectives

In this paper, we present our developments on micro-calorimeter arrays, based on High Impedance Silicon sensors (MIS or resistive TES) micro-calorimeters and GaAS-GaAlAs HEMTs / SiGe cryo-electronics, started 5 years ago. We show the pixel design, the main steps to build a 32x32 array. We are presently developing two kinds of high impedance sensors: Metal-Insulator-Sensors and High Resistivity Transition Edge Sensors. We described our associated FrontEnd electronics and detailed system level analysis of the foreseen camera. We discuss why we will be able to handle a camera with a large number of pixels (thanks to excellent thermal insulation and no electronic power consuming at the 50mK stage). We discuss the main technological building blocks (Absorber, Sensor) and their present status.