T he Norwegian atlas project Status report August 31st 2000
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Some of the equipment in the cleanroom at the Univ. of Oslo. Improved bonding facilities might be necessary for repair-bonding. Controlled storage and handling space and routines must also be developed. During the module construction period one to two technicians and three engineers will be involved (full or part time). One to two of the three engineers mentioned above, will carry out the testing in Oslo. In Bergen similar arrangements will be made to perform these tests. The sequence of electrical tests and repair of modules is not fully established yet. This is the most challenging aspect of the work over the coming year. The test methods may vary from injection of calibration pulses and pedestal runs to tests with radioactive sources and laser beams. Data for each electronic channel should be stored in the production database. The table below summarizes the module construction work accomplished and planned.
3.3 Cooling and hybrid prototyping.Several other activities should be briefly mentioned since the activities have involved many students over the last years and since some of these activities will be important for the future ATLAS program in Norway. 3.3.1 Cooling of the ATLAS ID silicon systems. One major challenge for the ATLAS silicon detectors, PIXEL plus SCT, is the low mass cooling system which is needed to remove around 60 kW, corresponding to 10W per module, of dissipated power in the active volume. The solution adopted is an evaporative fluorocarbon cooling system for the ATLAS SCT detectors. Data have been collected from cooling studies of prototype pixel and SCT detector structures, using perfluoro-n-propane (C3F8), -butane (C4F10), trifluoro-iodo-methane (CF3I) and custom C3F8/C4F10 mixtures. C3F8 gives the best performance and will be used in the SCT. Norwegian physicists and students at UiO, HiG (more recently) and SINTEF have worked actively with the evaporative cooling methods since 1992 concentrating on : Basics performance (the boiling process), heat transfer measurements, and capacity of such systems. Measurements and analysis of data for the structures (as shown in figure). Development of systems for control and monitoring of the cooling plant and structures. Norway is responsible for 37% of the cost of this cooling system. Revised cost-estimates indicate that the price will increase by 8 Mkr. This is due to the fact that water based systems have been banned in the ATLAS inner volumes (review in 1998) and that the power loads have increased by almost a factor two compared to the estimates made in 1994. Three developments are being pursued to ease this situation : Reduce cost to the bare minimum through technical developments. Find extra funding outside the current MoU agreement. Find extra funding in Norway and among the other partners in the project. The only conclusion which can be drawn at this point in time, is that this overrun is going to be difficult for the Norwegian groups to handle.  An barrel SCT stave being tested in the cooling lab at CERN. The drawing illustrates the thermal loads being used and the sensors which are being monitored during the test.
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