1. AdV - Internal Review of VAC subsystem
Cryotrap design, 04 Mar 09
Summary:
First issues from the 1st part of the review
2nd part : Agenda of presentations
Planning and manpower

2. Cryotrap impact on phase noise
Small-Large options similar vs vacuum performances = practically equivalent vs impact on phase noise,
Design is driven by mechanical design, installation risks, easyness of operation, budget , diffused light mitigation…
Optimization in progress: light shortening of the small trap (2.4m -> 2.0m )
_mechanical positioning of the ports for vacuum equipment
_favourable for diffused light issue
The average pressure increases by a factor about 1.5
phase noise for small and large traps , with low tube outg. to evidence performances

3. New trap : 2.0m long, 1m dia, 0.6m baffles, preliminary
Water pressure, torr
Safety factor vs goal pressure, 10-9mbar, is reasonabe

4. Bake-out equipment and experience

5. Bake-out equipment and experience

6. Traps periodical Regenerations
A first evaluation of deposited water on a trap:
regeneration of the trap driven by the extra-cost due to LN2 consumption and the general plan of the AdV activity. We don’t expect to regenerate traps more than once/twice a year.
A possible procedure , to be discussed
_close vacuum valves, remove LN2 from trap
_ purge with ‘hot’ GN2 (Pwater<Psat) 2 days, tbc
_ evacuation day
_ LN2 refill, cooldown
_ temp steady reached < 2 days

7. Plan and manpower estimation, in preparation
Dedicade web page by AdV coordinators
AdVplan
Design finalization
Construction tasks

9. 4 March ,
part II of the review: preliminary design, thermal and
diffused light issues, costs, planning, man power
Agenda of presentations
15' Trap mechanical design, J.VDBrand/M.Doets  15' Optical constraints and scattered light, C.Bradaschia  15' Thermal effects on test masses, A.Rocchi  60' General discussion