From: David Shoemaker [dhs@ligo.mit.edu]
Sent: Wednesday, October 22, 2003 6:06 AM
To: k.strain@physics.gla.ac.uk; Dennis Coyne; Alan Weinstein; coyne_d@ligo.caltech.edu; pf@ligo.mit.edu; ajw@ligo.caltech.edu; wilkinson@ligo-wa.caltech.edu; sanders_g@ligo.caltech.edu; Alan J Weinstein; seiji@ligo.caltech.edu; miyakawa_o@ligo.caltech.edu; dhs@ligo.mit.edu
Subject: 40m Discussion -telecon Tuesday, Oct 21, 10-12 Pacific

Skeletal notes from the 40m discussion. Please let me know if you want clarification/have corrections. 

Present: Alan, Ken, Peter, Carol, David, Seiji, Osamu.




objectives: 
  experiment largely built
  ready for the science
  want to plan this, make it responsive to AdL needs

  want to give Carol a plan we all believe in, hooks to other
  activities

slides from Alan
  http://www.ligo.caltech.edu/~cit40m/Docs/G030539-00.pdf

DTT needs to work better...

only a couple cables missing from LSC system
need some 166 MHz dets, and double demod board
but 90% in place

align commission optics: next month or two

Siesta: 
  want to keep our commitment to this at a minimum

Order of SRM and PRM commissioning
  commission -- maybe put a dogleg in

page 3 to be done in 3-6 months
  accuracy to date has been very good
  Alan's guess is 3 months, added 100% contingency


SRM e2e model, high fidelity needed, not in the next 6 months
  ??? Biplab ???

slide 4
  big question is time to get the DR working
  and simulation in parallel (or series if 40m not locking)
  Ken: need to have simulations 
  Finesse -- Seiji has done some work, but really want/need e2e

DC controls: guesses 150k for short MC controller etc.
  falls in FY05? needs a real grounds-up calc for the cost

slide 5
  wavefront sensing: currently only the input MC
  could be required just to get the thing going if unlucky

Interesting, but not needed, not part of the plan: 
  3.8 MHz: beyond the scope 
  multiple pendulums -- 
  thermal noise -- could be a limit
  QND limits -- 

  Virgo, Tama also interested in results, some potential collaboration
  need to monitor carefully any changes -- we can't increase our scope significantly

e2e folks are a staffing issue as well
  need to raise general conscience on this

Slide 7
  200k realistically estimated for new eq, 150 maintenance, guess
  complete grounds-up estimate needed

==================================
Peter's email:


i. Output mode cleaner:
   - a functional test of the opto-mechanical hardware and sensing/control
   scheme for the OMC (not necessarily a noise test)
   - Q: does/can the 40m have the in-vacuum real estate for this?

currently sketch: small chamber for Output optics, ~50cm; sketch is of
a PSL PMC and a MMT. Could be 2x longer maybe. Probably means a scaled
down version. Length scaling: longer means easier mode
matching. Numbers to be made 


ii. Auxiliary length sensing:
   - proof of concept
   - functional test of hardware
   - much or all of this will be in-vacuum -- does the 40m have room for
     it?

One possibility: send the beam back into 40m, more room in other
chambers, also possible for Output MC (I above)

biggest challenge is the engineering of the in-vacuum stuff, best by
far if full size. If can't do exact test, then maybe not burden 40m
with it. 

iii. Alignment sensing:
   - proof of concept
   - functional test of hardware

here proof of concept important. Also development/test of sensor


iv. ISC controls infrastructure
   - testbed for any new schemes regarding networking, signal processing,
     etc

obvious. incremental progress to match AdL schemes. 


v. Electronics module testing
  - goal: eliminate as many IFO re-designs as possible
  - requires an electronics savvy scientist

need to make sure that this is fulfilled. Barr? 

vi. Lock acquisition
  - hard to predict now how useful this will be

inputs, environment, and outputs are going to be pretty different. 


-----

Ben Abbott critical to the progress to date; try to preserve for the
40m if possible. 


Where ever it says measure noise --- not needed for AdL, hold to a minimum

Wavefront sensing: may need more priority.
  New, tricky, might take priority over OMC if time/money short
    
OMC should be developed somewhere else, and brought to 40m
  need to think about this -- Willems/Smith for optics, but
    controls in ISC. Should cause this conversation to take place

Money in LSC system for some of the elements in the 40m program
  may be double counting -- would rather have all elements of
  subsystem prototypes be counted in the subsystem RATHER than
  in 40m if possible. Keeps the responsibilities straight and double
  counting to a minimum. 

Manpower a critical issue, mostly in engineering -- Smith, Heefner, Bork, Abbott
  sharing and prioritization necessary across R&D
  may lead to less support for 40m, unfortunately