90 likes | 186 Views
Warming up for the OSD workshop. S.Hild and A.Freise January 2009. Reference layout of NDRC. See talk by Massimo. QUESTION => How much astigmatism is introduced by: Divergent beam (strong lens in input mirrors) passing BS and CP? Off axis telescopes of PRM1-3 and SRM1-3?
E N D
Warming up for the OSD workshop S.Hild and A.Freise January 2009
Reference layout of NDRC See talk by Massimo • QUESTION => How much astigmatism is introduced by: • Divergent beam (strong lens in input mirrors) passing BS and CP? • Off axis telescopes of PRM1-3 and SRM1-3? • QUESTION => How much astigmatism driven loss we can accept in PRC and SRC? • QUESTION => How to suspend PRM1, PRM3, SRM1 and SRM3? See talk by Matteo January 2009
NDRC with lenses moved to the BS • In case the astigmatism from the BS and the CPs is too strong… • IDEA: Move lenses out of input mirrors and put them close to the BS (out of IFO arms). • QUESTION => How to suspend the lenses in the BS tank? • QUESTION => Can we buy such lenses (quality, size, …) • QUESTION => Does the Non-Degeneracy still work in this setup? See talk by Roberto/ Giovanni January 2009
Long NDRC without lenses See slides from Andreas • In case we want/need a design without any lenses we have to make the recycling cavities as long as possible… • IDEA (from Julien): Move PRM2 into north input tank, passing the beam underneath BS and suspend PRM2 from IM reference mass. • QUESTION => Does non-degeneracy still work? • QUESTION => Is it possible to suspende PRM2 from the reference mass? • QUESTION => Can we fit beams into the vacuum? • QUESTION => Could we fit suspended 35 cm optics onto the injection and detection benches? See talk by Julien See talk by Carlo/Antonio See talks by Benoit and Eric ? January 2009
Pick-off beams • QUESTION => Which pick-off beams are necessary for ISC? BSAR? IM/CP? • Proposed Strategy: all secondary beams (4 beams from each CP, 2 beams from each IM, 3 beams from BS = TOTAL about 15 large beams) are either detected or properly dumped. January 2009
Pick-off beams from IM and CP • QUESTION => Can pick-offs, consisting of several beams, be used for ISC purpose? • QUESTION => Is it possible to deal with divergent pick-off beams (up to about 1m diameter!) • QUESTION => Do we have the space direct pick-offs in 4 different directions (below, above, left and right of main beam)? This plot is only to show effects qualitatively. A proper CAD drawing is required… January 2009
Eliminating pick-offs from IM and CP? • We could get rid of the pick-off beams from the IM-AR by making them etalons: • QUESTION: Are the etalons required for reducing noise couplings? • QUESTION: Would it be possible to control an IM etalon? • In principle we could get rid of CP secondary beams by aligning the CPs to the main beam: • QUESTION: Any noise problems from additional low finesse Fabry Perot? • QUESTION: Is it possible to keep the CPs aligned (refernce mass moves when actuating on main test masses)? January 2009
Extraction of pick-off from BS-AR • Pick-off from BS-AR coating needs to separated from the main beam before being reflected back into the interferometer from the Signal-Recycling mirror. • IDEA: Extract the BSAR-pickoff close to the beam waist between SRM2 and SRM3 (should work even without BS wedge). • QUESTION => Is it possible install a beam director between SR tower and detection tower? • QUESTION => How to dump the other secondary beams of the BS-AR? January 2009