1. SCT Material Stephen Haywood Rutherford Appleton Lab

2. IDSG 9 June 2006 SCT Material 2 Stephen Haywood Apologies I was asked to coordinate SCT X 0 effort. RAL well placed  Some of the key engineers for Barrel & End-cap  Experience of Barrel & Disc Services Assembly  Design of much of the “off-detector” services up to PPF1 & TEs With the departure of Debbie Greenfield, I have been consumed with EC Engineering at RAL. The amount of work to do has been much more than expected and subsequent problems have caused this to go slowly. Engineers have been too busy designing/producing/assembling hardware to have time to supply all info. Lot of effort gone into chasing people. My slow progress has caused others to take the initiative and do some of the work – with a possible loss of coherence. I have struggled to keep my eye on the ball.

3. IDSG 9 June 2006 SCT Material 3 Stephen Haywood Aims In the Physics TDR, I proposed that satisfactory understanding of electrons (in particular cross-calibration of ID and ECal through E/p) requires a “local” understanding of X 0 at the level of O(1)% of its value. Lot of discussion about this: It is tough to reach this precision. Not trivial to do from data (conversions, electron fits). Consistency of mass measurements with Discs gives encouragement that O(1)% is achievable. But need to have a good understanding of material compositions and corresponding X 0 s. So O(1)% provides a target – unless we try, we won’t achieve and run the risk of being far from a satisfactory level.

4. IDSG 9 June 2006 SCT Material 4 Stephen Haywood Plan The Plan was/is: 1. Gather Info in a coherent form:  20 months ago, info was requested from a list of Responsibles.  Request Word Pro-Forma to be completed, supplemented by speadsheets. 2. Process that Info to create a “paper description” or Model:  Perform averaging of masses of different components.  Identify suitable Volumes for Simulation: size, location, mass.  Identify material composition within each Volume. 3. S/w people (was Grant Gorfine, now Pat Ward) incorporate Volumes into S/w description, ie. G4/GeoModel. 4. Check what is in Simulation with measured masses.

5. IDSG 9 June 2006 SCT Material 5 Stephen Haywood Philosophy This is a long-term, detailed and methodical approach intended to get an accurate and complete description of the material in the Simulation. It would be relatively easy to produce spreadsheets which gave the average X 0 in the centre of the Barrel – this is not our aim. We need to cope with all the complications and irregularities as a function of (  ). (The problem is very complicated and I believe not solved by trivial spreadsheets … only capturing the info in the Simulation will give us a satisfactory description of X 0.) So this approach does not lead instantly to plots of X 0. Meaningful plots will only be available once sufficient info has been incorporated into the Simulation code.

6. IDSG 9 June 2006 SCT Material 6 Stephen Haywood Info at: http://hepwww.rl.ac.uk/atlas-sct/engineering/material_budget/

7. IDSG 9 June 2006 SCT Material 7 Stephen Haywood Info Gathering Status file – shows interaction with Responsibles. Green – I have info Yellow – info being collected or available; not yet received by me Red – info not gathered

8. IDSG 9 June 2006 SCT Material 8 Stephen Haywood Achievements Barrel Modules – GeoModel description by Daisuke Naito et al End-cap Modules – GeoModel description by Peter Kodys Barrel Services – description being developed by Taka Kondo et al Disc Services – model constructed by Haywood and GeoModel description coded by Gorfine

9. IDSG 9 June 2006 SCT Material 9 Stephen Haywood Summary InfoModelGeoModel Barrel Module Done; now check On-Barrel Services Almost completeGood progress Supports TE Start soon Off-Barrel Services Start soon End-cap Module Done; now check On-Disc Services Almost complete On-Cyl Services Started Supports TE Good progress Off-EC Services Not started

10. IDSG 9 June 2006 SCT Material 10 Stephen Haywood Future Pat Ward has taken over from Grant Gorfine and is now actively creating new GeoModel entities: finishing off On-Disc Services. To move things forward at RAL, Alessandro Tricoli (new RA) is working with Taka Kondo to complete the On-Barrel Services. I will not have significant free time until mid-Jul (?), then: 1. Revisit collection of Info, esp masses – chase people (once more) ! 2. Complete Model for End-cap On-Cylinder Services. 3. Do everything else ! There is a lot to do and many of the key people are very busy !