1. GG3 Operations & Reliability (Availability) Eckhard Elsen (Eckhard.Elsen@desy.de ）Eckhard.Elsen@desy.de Tom Himel (thimel@slac.stanford.edu)thimel@slac.stanford.edu Nubuhiro Terunuma (Nobuhiro.Terunuma@kek.jp)Nobuhiro.Terunuma@kek.jp

2. Goals and Questions to be Addressed Goals and Plans of GG3 GG3 will cover operations issues including attaining a high availability, special needs for commissioning, and the machine and personnel protection systems. The spotlight will be on ways these requirements effect major machine design decisions. The output of the group should be a list of how operations is effected by some of the design choices and a list of features needed to attain an ILC that will efficiently integrate luminosity. In cases where we cannot answer the questions, we should describe the work needed to attain the answer and find someone to do that work. Picked up from the Snowmass 2005 Web

3. GG3 Operations & Reliability (1st week) Tuesday (8/16): Availability & Recovery 10 ~ 15 persons (~3 Asia) 16:00 - 16:15 Benchmarking Availability code, S Schaetzel 16:15 - 16:55 Availability simulations, T Himel 16:55 - 17:30 Sources & Tunnels, Discussion --> Postponed to 2nd week Wednesday (8/17): ILC Commissioning minutes 10 ~ 20 persons (~5 Asia) 16:00 - 16:30 ILC commissioning from a HERA perspective, F Willeke 16:30 - 16:45 ILC commissioning Schedule, J Sheppard 16:45 - 16:55 ILC commissioning ideas from the TESLA TDR, K Floettmann 16:55 - 17:30 Requirements, Discussion Thursday(8/18): Protection Systems --> Postponed to 2nd week Schedule1

4. GG3 Operations & Reliability (2nd week) N.Terunuma did not stayed on 2nd week. Tuesday (8/16): Availability & Recovery Wednesday (8/17): ILC Commissioning minutes Tuesday(8/23): Protection Systems 16:00 - 16:35 Fast MPS for ILC, P Tenenbaum 16:35 - 16:55 Dump layout, Discussion 16:55 - 17:20 Requirements for MPS & PPS, Discussion 17:20 - 17:30 Other discussion and our assigned questions Wednesday(8/24): Pros/Cons and planning 16:00 - 16:55 Generate lists of pros/cons for all questions involving GG3 16:45 - 17:30 Make plans for future work Schedule2

5. Availability (Simulation Study) Benchmarking Availability Code with HERA, S.Schaetzel well reproduced failure numbers indicate that the failures are consistently generated in the program, i.e. a consistency test of the code Availability Simulations for ILC, T.Himel Key assumptions: MTBFs and MTTR Mean Time Between Failures Mean Time To Recovery Undulator requires availability of electron beam. two tunnel system achieves 78%, a single tunnel 64% availability. MTBF of several components have to be increased by factors up to 20 to yield an 85% uptime. Picked up from Notes by Eckhard Elsen; 8/18, Picked up from Notes by Eckhard Elsen; 8/18, Availability

7. Full list of Components

8. One vs Two Tunnels (cont.) Reliability studies favour 2 tunnel solution (recommendation from WG2/GG3 based on these studies) Nick Walker; 8/26, Status of the ILC Accelerator Design

9. People generally agreed with the above notes on the 3 talks. The control system must be able to record synchronized data of many time scales from many systems to allow fault analysis Need naming and numbering conventions that are followed. It would be nice to have DR not with linac to give more commissioning time of the DR while the linac is under construction. The effect of 1 vs 2 tunnel and DR location on phased commissioning are important and need further work in week 2. Tom Himel; 8/18, Tom Himel; 8/18, Notes from Commissioning Session of GG3 Commissioning Discussion -1/2-

10. Commissioning Discussion -2/2- The method of energy upgrade will effect commissioning. Needs further work in week 2 It would be nice to have a keep-alive type e+ source to commissioning the e+ system (in addition to the e- source) Diagnostics should function at 1% beam intensity for commissioning and MPS recovery. It is OK if wire scanners are replaced with profile monitors for this. An automated alignment system that runs on tracks and automatically surveys component positions would be very useful Tom Himel; 8/18, Tom Himel; 8/18, Notes from Commissioning Session of GG3

11. Running out of time…. Main accelerator beam dynamics (WG1) Bunch Compression (WG1) –Recommendation: 2 stage preferred (6mm→150  m or 9mm → 300  m) Instrumentation (GG2) –BPMs, wire scanners (laser-wire), MPS issues, etc. Machine Protection System (GG3+GG2+WG1) –Very high risk (US LC options study) Operations, reliability, commissioning (GG3) –Major issue for complex machine Cost & Engineering (GG4) –Cost is everything! Much much more…. An incredible amount of work has been done/presented at this workshop! Nick Walker; 8/26, Status of the ILC Accelerator Design

12. Eckhard Elsen is preparing a write-up of GG3 - a draft should soon be available. More Details See… http://alcpg2005.colorado.edu:8080/alcpg2005/progr am/accelerator/GG3