N. Dumont-Dayot

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.

PERFORMANCE OF THE LIQUID ARGON FINAL CALIBRATION BOARD

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Performance of the liquid argon final calibration board C. De La Taille, N. Seguin-Moreau, L. Serin, N. Dumont-Dayot, I. Wingerter-Seez

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.

Calibration boards for the ATLAS LAr calorimeters

In order to calibrate the ATLAS Liquid Argon (LAr) calorimeters to an accuracy better than 1%, over 16 bit dynamic range, chips have been designed in DMILL technology. The design and performance of a 16 bit DAC, a static low offset operational amplifier and a digital chip to control the calibration boards are presented. A 8 channels board using these chips has also been realised and carefully measured as this module will be replicated 16 times to design the final 128 channels calibration board.

The ATLAS calorimeter calibration board : tests of a first set of boards

The ATLAS Liquid Argon electromagnetic calorimeter needs a very accurate calibration system in order to fulfill its physics requirements. A set of 10 calibration boards has now been produced to test the calorimeter modules in electron beam. These boards contain a programmable sequencer which allows the loading and execution of a complete calibration run (various DAC values, delays and patterns) and provide 128 signals which are injected to the electrodes through high precision resistors. Measurements have demonstrated a good uniformity and a good linearity though small distortions have been identified. Radiation tests with both neutrons and gammas have shown many shortcomings in the pulser and control logic. New developments to address these shortcomings are discussed.