Full DSO tests are a prerequisite for injection.
Earliest date that DSO tests could start is July 26.
2 weeks of tests would then result in DSO approval by August 8.
In general, this proposal is agreed by the 4 experiments (some details to be sorted out).
If this schedule holds, could inject beam August 9/10.
For beam, CMS shielding needs to be closed to avoid lengthy approval of compensatory measures. Could close for injection, then open after. Takes of order 1 day to open or close. CMS seem OK with this.
Conclusion; aim for injection of beam 1 (from 2 to 3) August 9/10.
Sector test is a standard procedure for all large accelerators. Performed thoroughly it has the potential to reveal potentially major problem (see LEP, RHIC etc). If things are OK, all well and good, if there are problems the test gives us appreciable lead time. In this sense the test clearly allows for risk minimisation.
| System | Integration issues |
| Power converters | full chain, transfer functions, FiDeL etc. |
| Magnetic Field Model | transfer functions, harmonics, cycling etc. |
| Injection Kickers | pre-pulses, diagnostics, interlocks |
| Septa | diagnostics, interlocks |
| TDI | controls, interlocks |
| Collimators | control, diagnostics |
| Instrumentation: Screens, BCT | basic operation with beam |
| Instrumentation: BPMs | concentration, timing, RT |
| Instrumentation: BLMs | interlocks, critical settings |
| RF low level | synchronisation, pre-pulses, fast timing |
| BST | RF/timing synchro etc. |
| Timing | Test full chain - events, injection requests etc. |
| Controls infrastructure | Whole chain. |
| Beam Interlock System | Kickers, safe beam parameters, beam dump, BLMs |
| Software Interlock system | With beam |
| Access system | LHC Access project is motivated by the sector test to debug its numerous sub-systems and test all the operational procedures such as the patrol. |
| Radiation monitoring | |
| Radiation protection |
Note experience in this area, TT40: wrong vacuum chamber, corrector polarity errors, BPM polarity errors, screen polarity errors
Tool debugging - it will be required.
Subsidiary systems ready on time
Is there time enough left to change anything? Yes. There had better be.
Time foreseen in commissioning plan for injection and first turn of ring 2: 4 days - optimistic if none of the problems forthcoming in the sector test have been resolved. Time spent during the sector test will be directly recuperated.
For proper understanding of the LHC and safe, effective commissioning, these measurements will have to be done during the commissioning phase. Time spent during the sector test will be directly recuperated.
- Commission TI 2 end, injection and thread to IR3
- Commission trajectory acquisition and correction
- Polarity checks
- Commission Beam Loss Monitor system
- Optics measurements
- Aperture checks
- Effect of magnetic cycle
- Field quality checks
- Quench limits and BLM response
- Setting up of injection machine protection
Pre-test commissioning of all systems listed above plus subsequent problem resolution, analysis, improvements...
Commissioning of all systems together plus subsequent problem resolution, analysis, improvements...
Less to do in the narrow window for operation machine checkout following the end of hardware commissioning.
Two points here:
In fact, on reflection, the time spent on the sector test is, give or take some minor planning adjustments, recoverable.
Problem resolution - lead time - risk reduction
- beam related problems tend to arrive serially, and are solved one at a time. If during full commissioning and under pressure, the quick fix will always be adapted.
WILL THE SECTOR TEST DELAY THE START OF LHC COMMISSIONING WITH BEAM?
Properly planned should have no significant impact on installation schedule. There is a significant gain if there are problems.
The test in 2008 can be performed largely in the shadow of ongoing commissioning. The shift to 2008 reduces considerably the potential impact on: transport, installation, LHCb.