Tilecal session in ATLAS upgrade week (Tuesday 10 November 2009) Alternative drawer mechanics solutions Tilecal session in ATLAS upgrade week (Tuesday 10 November 2009) François Vazeille What are the constraints? Proposed R&D scheme Sharing of activities 1

What are the constraints? 1. The most important constraint The time requested to recover the PMTs, then to rebuild the Drawers with the new electronics. • Till now: 18 months were scheduled in the long shut down, but even though they became 24 months or more  We should face to a very big challenge. • Proposed solution: - To make new Drawers, taking benefit from the past experience and from new ideas both on the electronics and on the mechanics. - To pre-instrument them with the maximum of new electronics (and services), but for the PMT blocks that will be extracted during the long shut down. - The realistic strategy must be defined, requesting the contributions of many Institutes during the dismounting and latter phases. 2

2. Other constraints … already given in my previous talks (see the previous meetings). • The Tilecal Modules like they are and will stay: same specifications as for ATLAS. • The allocated space for access: now best understood than at the design epochs of ATLAS Drawers. • The experience on Drawers and handling tools. • The new electronics - Less cards, new power consumption (impact on cooling). - Independent Drawers: Super-Drawer concept abandoned. - An optimized approach of services, cooling, mechanical links. • In any case, the cost and the funding will drive the final solution 3

Proposed R&D scheme 5 steps are identified, some of them being made in parallel if manpower available. 1. Sliding study of n linked Drawers (with n2) inside Girders. Theoretical and practical study fixing the maximum value of n. n>2 would correspond to mini-Drawers. 2. Study of Cooling circuitry of linked Drawers. Fully depending from the final new electronics: dissipated power, possible space at the previous HV side (if HV off Drawer). 3. Study of services: signals, powers, cooling both inside the Drawers and the Fingers. 4. Handling tools, including the access aspects. 5. Scenario of new making and insertion of Drawers, including the pre-instrumentation and the final instrumentation. • These 5 points have not the same urgency, the more as some of them are fully depending from the final choice of the new electronics. • Point 1 should have a conclusion before end of 2010. • Milestones have to be agreed on other Points. 4

Sharing of activities The Clermont-Fd team is officially authorized (by LPC management) to work on Point 1 (Sliding studies) in 2010, and to contribute to Point 5 (Strategy). - Manpower: 1 Engineer + 0.5 Technician. - Depending from the results: new requests will be made later on other activities (Perhaps Point 2: Cooling). There is space and needs for other Points, in particular Points 3 (Services) and 4 (Tools). 5