件名 : SCT GeoModel[Mon, 21 Aug 2006 10:27:04 +0100 (BST)] 送信者 : Pat Ward 宛先 : A.Tricoli@rl.ac.uk >>> Dear Alessandro, Stephen, Taka, I have been comparing Alessandro's spreadsheets with the existing GeoModel barrel geometry, and deciding how best to implement the new model. In general, I favour making as few changes as possible to the existing volumes, but updating masses and compositions where necessary. I have written some notes below on what I propose to do, and I think we should discuss these. I do not want to commit any changes, particularly to the database, until we are all agreed that we now have the best model. I don't know how we are going to manage this discussion: I know Alessandro is away this week, and then I am away for the following 2.5 weeks, but I may as well circulate these thoughts now, and feedback welcome. Regards, Pat Notes for discussion on new barrel services geometry. CPW 18/8/06 ==================================================== Dogleg ====== Current Alessandro ------- ---------- Thickness/mm (r) 1.0 0.34 Length/mm (phi) 36.0 76.8 Width/mm (z) 30.0 26.0 Volume/cc 1.08 0.78 Mass/g 6.9552 5.71 Density/(g/cc) 6.44 8.41 * Propose to keep current dimensions and position but update mass and composition. Length cannot be extended without overlapping cooling pipe. * Why is new mass lower? This is 'dogleg+top bracket' option. Cooling Block ============= Current Alessandro ------- ---------- Thickness/mm (r) 1.5 5.0 Width/mm (phi) 8.0 8.0 Length/mm (z) 62.0 62.0 Volume/cc 0.74 2.48 Mass/g 2.418 3.62 Density/(g/cc) 3.25 1.46 * Suspect mass difference because Alessandro has included solder, clips, etc. and current value only include block (current material = Al). Is this so? * Propose to keep current dimensions and position but update mass and composition. There is no room to increase thickness. Cooling Pipe ============ Current Alessandro Drawing ------- ---------- ------- Radius/mm 2.0 1571.76 Length/mm 2.1 1471.6 Radial position/mm (3) 304.8 306.9 307.1/309.7 (4) 375.7 377.9 378.0/380.6 (5) 447.4 449.9 449.7/452.4 (6) 518.1 520.9 520.4/523.1 * Current positions (estimated from entry points of particles) are 2-3mm inside values suggested by Alessandro and drawings. Propose to leave them there - moving likely to cause huge problems. * Length will be updated to 'whatever is convenient'. I think the radius can be increased, but am not sure it is worth it. Mass and composition will be updated. Bottom Bracket ============== Current Alessandro ------- ---------- Thickness/mm (r) 4.0 3.2 Width/mm (phi) 8.0 7.5 Length/mm (z) 51.0 54.0 Volume/cc 1.63 1.30 Mass/g 4.94496 2.68 Density/(g/cc) 3.03 2.07 * Why the mass difference? Think Taka includes an 'interface PCB' and Alessandro does not (I think this is in Alessandro's harness). This needs checking. * Propose to keep current dimensions and position, update mass and composition. Harness (Power Tapes) ===================== Contained within a volume: Current Alessandro ------- ---------- Thickness/mm (r) 1.221 1.97 Width/mm (phi) 21.0 24.66 Length/mm (z) 1571.76 1423.1 Mass/g 33.5025 93.4 * Within this volume are 2*6 tapes (each thickness 1.221/6mm) stacked in r, running from the interlink to each dogleg. Propose to keep this structure, but increase tape thickness (to ?) and reduce length to make end at end of cylinder. * Why now so much more mass? Seems to be because the current 'power tapes' include only power tapes, whereas Alessandro's harness includes fibres, interface PCB, connectors as well. The power tape component of this is 33.34g which is similar to current power tapes - is the rest really so much more? I think some of the stuff Alessandro has included in the harness has probably been included by Taka in the dogleg or brackets - they should check, if they haven't already done so. In which case, do we want to move it into the harness, smeared out along z, or keep it in the doglegs and bracket, concentrated in z? * Should the interlink volume be at |z| = 765, rather than current position just inside thermal shield? And where should thermal shield be? Cylinder, Flange, Clamp ======================= * Propose to change geometry here to match Alessandro's dimensions, layout and materials, except that the clamp will start outside the auxilliary layer, i.e. there will be a 2mm gap between the harness and the clamp (in r). Cooling Inlet/OutLets and U-bends ================================= * Propose to implement a simplified model of these in the first instance: a tube with r_min = r_max of clamp r_max = r_min + 10 mm extending in z from the end of the modules (z = 747mm) to the end of the barrel (z = 765 mm). At some future date, it would then be possible to split this tube into segments with alternate segments filled with different materials to simulate the in/outlets separately from the U-bends. And even to put smaller volumes inside the segments if necessary. But the overall envelope would be the same at each end, and the cooling pipe just runs between these envelopes.