Uppsala : Mounting of hybrids on the modules, bonding of all modules, tests and repair of complete modules.
The Norwegian groups have over the five last years prepared three facilities for ATLAS silicon module construction:
A cleanroom laboratory for silicon detector tests and studies at UiB.
A cleanroom for module construction and a clean area for module testing at UiO.
An electronics lab for hybrid testing and testing of the completed modules at UiO. (A similar lab will have to built up at UiB over the coming 12 months ).
The ATLAS project has involved a substantial investment in facilities at the local institutes. The infrastructure upgrades include 2.5 Mkr in basic equipment and rooms, and 15-20 man-years of work funded by the Universities. Special equipment for around 1.5 Mkr has been purchased, covered by the Norwegian Research Council, over the last 5 years.
At Gjøvik an ATLAS detector control system (DCS) has been set up. The ATLAS DCS rely on PCs connected to CAN nodes in a Bridgeview software environment. Two students at Gjøvik, now master degree students at the Institute for Informatics (UiO), and two new students at Gjøvik have worked with this system and also visited CERN several times. Two other students have worked with tracking and pattern recognition problems which also rely on local PCs and software packages.
The cryogenics involvement of NTNU does not rely on local infrastructure but rather on local know-how and expertise. The group has over the last 6-8 years worked closely with the CERN ST group within cryogenics and have sent 1-2 technical students to CERN every year.
1.4 Financial overview (in 1000kr units = 1 kkr).
In general the Norwegian ATLAS budget will cover the MoU cost, travels and operation, and a minimal Dr.scient grant program for the project. In addition the project manpower budget post provides the specific technical expertise in form of engineering effort or post.doc positions necessary to carry out the project. The sensors are funded through a separate budget line (“Tungt utstyr”).
One problem is that the prototyping costs have been underestimated by 600-1000 kkr. The most important overrun was caused by one extra prototyping run in 1998-99 for silicon sensors, to test the radiation hardness of oxygenated silicon, which was advocated as very promising by the RD48 (ROSE) collaboration. This was not foreseen in our planning. Furhermore, the cost for necessary upgrades of laboratory facilities in Bergen and Oslo were not fully covered in early budget estimates. The overruns have so far been contained and partially recovered by keeping some project manpower posts free.
Today we are aware of four potential financial problems; the sensor costs might overrun, depending on the breakage during construction, the Common Fund contacts with SB-verksted is slightly high, the cooling costs have increased very significantly and an extra contribution of around 2 MNOK for integration of the ATLAS Inner Detector and for Maintenance and Operation (M&O) will be requested for the period 2001-2005.
One engineer was hired on the project in the Spring 2000 and a Post.Doc or engineer should be hired soon to take on responsibilities during the module production phase. Therefore we do not expect to be able to recover significant amounts from the manpower budget. An additional uncertainty is the exchange rate as most of these funds are at CERN (CHF) and the contracts are placed in Norway (NOK).
The main Norwegian financial contribution to the ATLAS SCT is silicon sensors (8800 kkr) and hence the development of good silicon sensors suitable for LHC has been given high priority over the last 3 years. These detectors will be used in the modules constructed in Scandinavia and competence in detector development and testing procedures are crucial for the success of the project.
The silicon microstrip detectors that make up the SCT system of the ATLAS experiment will operate in radiation levels significantly greater than those in current experiments. The high radiation levels arise primarily from the large number of minimum bias interactions that occur during each beam crossing. The radiation damage is therefore dominated by low momentum pions, and other hadrons from these interactions. In addition there are neutrons resulting from backscattering from the hadron calorimeters into the central tracking region. The largest radiation levels are close to the interaction region. In the innermost barrel of the SCT the level of irradiation corresponds to 3 x 1014 1 MeV neutrons per cm2 over ten years of ATLAS operation. After this dose, the voltage required to obtain a satisfactory collection of the free ions produced by the traversing particle is expected to be very high, around 300V. The challenge to the manufacturers is to mass-produce detectors that will survive such high voltage operation after being subjected to large doses of radiation. Following the very positive indications by the CERN RD48 collaboration (ROSE) that silicon containing some amount of oxygen improves radiation hardness, a special order of oxygenated detectors was placed with SINTEF. Studies of these show that oxygenation is beneficial, in particular because reverse annealing effects seem to be slowed down, The benefits seem to be smaller than expectation from the early studies by the ROSE collaboration. No disadvantages of oxygenation have so far been seen. Studies are still to be completed.
2.1 Infrastructure for detector tests. As Bergen is the only place to assure the quality of SINTEF detectors we need to be able to do all tests which are to be performed during qualification of the preseries and during series production. The most important tools for detector tests, an automatic probe station, current and capacitance meters, have been operational in Bergen for a few years. A number of upgrades have been performed over the last year to move into serial production testing of the detectors. In collaboration with the group for Space physics at the institute, a new cleanroom laboratory has been constructed. The air quality of the new facility designed to reach 1000 particles per cubic foot. This laboratory was operational from the beginning of June, just in time to permit tests of the preseries detectors. New equipment acquisitions include video facilities, a new capacitance meter (to measure at low test frequencies) and a multimeter/data acquisition system. Test data are transferred to a central SCT database whch has been successfully installed for use from Bergen. Furthermore equipment for electronic tests of detectors is being set up. This will consist of two systems – one for detector tests with fast analog electronics, and one system for tests of finished detector modules.