N. Massol

The evaporative cooling system for the ATLAS inner detector

This paper describes the evaporative system used to cool the silicon detector structures of the inner detector sub-detectors of the ATLAS experiment at the CERN Large Hadron Collider. The motivation for an evaporative system, its design and construction are discussed. In detail the particular requirements of the ATLAS inner detector, technical choices and the qualification and manufacture of final components are addressed. Finally results of initial operational tests are reported. Although the entire system described, the paper focuses on the on-detector aspects. Details of the evaporative cooling plant will be discussed elsewhere.

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.

The ATLAS LAr calibration board

In order to calibrate the ATLAS Liquid Argon calorimeters to an accuracy better than 1%, over 16 bits dynamic range, 2 prototype boards with 128 pulse generators have been built using DMILL components. The logic of control is able to enable the required channels, to load the DAC value, to delay and send the calibration command. The DAC voltage is distributed to the 128 channels in order to produce the 2 μA – 200 mA precision current. The voltage to current conversion uses a low-offset opamp and a 0.1% 5Ω resistor. Exhaustive measurements have been performed on this prototype (uniformity, linearity, jitters ...) and will be presented in detail.

ATLAS/Lar calibration system

The liquid Argon calibration board has been designed to deliver a uniform stable and linear signal whose shape is similar to calorimeter ionisation current signal over 16 bits dynamic range. 3 versions of boards with 128 pulse generators have been built using DMILL components. The performance have been measured on the last prototype (amplitude and timing measurements, linearity, uniformity, jitters,...) and will be presented in detail. Boards qualification for the whole production next year will be described.