SCT Material

Stephen Haywood Rutherford Appleton Lab

SCT Material 2Stephen Haywood IDSG 9 June 2006

ApologiesI was asked to coordinate SCT X0 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.

SCT Material 3Stephen Haywood IDSG 9 June 2006

AimsIn 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 X0 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 X0s.

So O(1)% provides a target – unless we try, we won’t achieve and run the risk of being far from a satisfactory level.

SCT Material 4Stephen Haywood IDSG 9 June 2006

PlanThe 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.

SCT Material 5Stephen Haywood IDSG 9 June 2006

PhilosophyThis 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 X0 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 X0.)

So this approach does not lead instantly to plots of X0. Meaningful plots will only be available once sufficient info has been incorporated into the Simulation code.

SCT Material 6Stephen Haywood IDSG 9 June 2006

Info at:http://hepwww.rl.ac.uk/atlas-sct/engineering/material_budget/

SCT Material 7Stephen Haywood IDSG 9 June 2006

Info GatheringStatus file – shows interaction with Responsibles.Green – I have infoYellow – info being collected or available; not yet received by meRed – info not gathered

SCT Material 8Stephen Haywood IDSG 9 June 2006

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

SCT Material 9Stephen Haywood IDSG 9 June 2006

SummaryInfo Model GeoModel

Barrel

Module Done; now check

On-Barrel Services Almost complete Good progress Good progress

Supports TE Start soon

Off-Barrel Services Start soon

End-cap

Module Done; now check

On-Disc Services Almost complete Almost complete

On-Cyl Services Started

Supports TE Good progress

Off-EC Services Not started

SCT Material 10Stephen Haywood IDSG 9 June 2006

FuturePat 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 !