Results on 0.7% X0 thick pixel modules for the ATLAS detector

Modules are the basic building blocks of the ATLAS pixel detector system, t hey are made of a silicon sensor tile containing similar to 46 000 pixel ce lls of 50 mum x 400 mum, 16 front-end chips connected to the sensor through bump bonding, a kapton hex circuit and the module controller chip. The Pix el detector is the first to encounter particles emerging from LHC interacti ons, minimization of radiation length of pixel modules is therefore very im portant. We report here on the construction techniques and on the operation of the first ATLAS pixel modules of 0.7% radiation length thickness. We ha ve operated these modules with threshold of 3700 x 10 +/- 300 x 10, mean no ise value of 225 x 10 and 0.3% dead channels. (C) 2001 Published by Elsevie r Science B.V.