ISC worshop 13/03/2009 - Minutes of meeting

Participants:

H. Heitmann, G. Losurdo, M. Mantovani, G. Vajente, E. Tournefier, M. Barsuglia, F. Cavalier, F. Bondu (minutes)

Excused:

P.-F. Cohadon, A. Brillet

Introduction talk by F. Bondu and discussion:

G. Losurdo will talk with F. Bondu about an Internal Review Committe and its charge.

Lock acquisition talk by F. Cavalier:

* Discussion on slide 1: which points are necessary? For G. Vajente, 1 and 2 are equivalent. F. Cavalier mentions that the auxiliary laser may allow the lock acquisition of the central interferometer also (point 3). F. Bondu doubts that the auxiliary laser will be stable enough (arm cavity linewidth is 50 Hz, recycling cavity LW 5 Hz?).
G. Vajente raises that there is no simulation  supporting the variable finesse technique for AdV.
* Slide 2: simulation with CALVA parameters (FSR=10 MHz, LW~10 kHz).

* Integration of auxiliary laser to be included on DET planning.

* F. Cavalier asks for a firm answer on ESPCI participation (bench design, simulations) by 10 days from now.

* LAL not available/maintain to develop a general purpose simulation tool

* LAL is responsible for:

- simulation for a lock acquisition of long arms with auxiliary laser

- specifying the auxiliary laser stabilities

- comparing auxiliary laser with alternative techniques

F. Cavalier will deliver a first planning on March 15.

A discussion on planning will take place on week 13, starting march 23.

Alignment talk by M. Mantovani:

Manpower clearly identified. A request to collaboration/EGO to be written and supported by G. Losurdo.

Need for a meeting to discuss simulation tool.

Pick-offs: check with OSD that there is no problem.

Steady State Control talk by F. Bondu:

Small Schnupp asymmetry granted.

G. Vajente comments on slide 6 ("hidden" DoF) that the situation is already present in AdV, solved by hierarchical gain technique.

G. Losurdo: determination of tower positions is urgent.

Modulation frequencies determination is ISC responsibility, numbers determined by A. Freise are TBC.

Other comments:

M. Barsuglia suggests to make explicit that the laser power level should be adjustable during the lock acquisition.

He also suggests to set requirements on thermal transients for the lock acquisition.

Conclusions:

* F. Cavalier commits to activities related to the lock acquisition of the long arms. Answer to ESPCI commitment in the next two weeks. Planning due on March 15th.
* G. Losurdo points out that work on modulation frequencies / tower position is urgent, because of implications in other subsystems (IME, VAC).
* G. Vajente urges to make progress on the double/single demodulation scheme, as this is important for INJ.
We should understand why LIGO does not have amplitude modulation.
* M. Mantovani needs to identify a simulation software. A dedicated meeting to be organized in the next two weeks.
* Meeting on parametric instabilites to be organized.
* No responsibility holder identified up to now for the simulation of the lock acquisition of the whole interferometer (test variable finesse, test thermal transients effects).