WBS 3.3 Laser Facility

Jim Bell, Jason Chin, Erik Johansson, Chris Neyman, Viswa VelurJim Bell, Jason Chin, Erik Johansson, Chris Neyman, Viswa VelurDesign Meeting (Team meeting #11)Design Meeting (Team meeting #11)

November 05, 2007November 05, 2007

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Agenda

• Discussions at CfAO retreat on Sodium Return• Feasibility of SOR and LMCTI lasers • Other progress

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Sodium Returns

• Sodium Return– Discussions at CfAO shows there are still large uncertainties in

determining sodium returns.– The best data we have currently comes from the SOR and the

Gemini North System.– Circular polarization factor is diminished by Mauna Kea’s latitude

as compared to SOR. The 2x factor may be closer to that of GN’s 1.3.

– SOR’s next generation dual frequency pump laser of D2a and D2b will increase return by a factor of 1.6.

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Laser Architectures• Stable Laser Platform (SLP)

– Laser is on or below the Nasmyth Platform.

– No dependency on a moving gravity vector.

– More complex laser beam transport system, use of fibers, likely more throughput losses.

• Moving Laser Platform (MLP)– Laser is on the elevation

ring.– Dependency on a moving

gravity vector.– Added complexity for

installation on the elevation ring.

– Improved throughput.

Laser Launch TelescopeLocation

Location 1(behind HIRES)

Locations IIIon side of Elevation Ring

Existing HIRES Instrument

AO Enclosure/Electronics Vault

FRONT VIEW

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What’s happening at SOR?• Current AFRL plans

– In process of fabricating a new and improved SOR unit.– New SOR system is expected to see improvements in power, 50%.– Redesign of optical bench to include modular design. Modular design of

amplifiers will provide additional stability and simplicity. Reduce size of optical bench; but likely increase due to double pumping.

• Improvement in the NPRO engine for higher output.

• Removal of OTS units for better stability.

• No plans for a gravity moving vector system; but expects the new redesigns and modules to be able to handle a changing gravity vector.

• Improvement to stability using hallowed out machined mechanical blocks.

– Second system for Maui will be more similar to the existing system than new system. SOR will used 14 existing NPRO engines.

• Funding of the Maui System is not concrete. A laser is expected as part of the new AO system at for Maui.

• Maui system will not have a changing gravity vector; although optical bench is vertical.

– AFRL currently moving forward with design of new SOR system.

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SOR Feasibility

• Using SOR’s system with a MLP architecture.– High power supplies in thermal enclosure on the Nasmyth Platform.

– Large gauge low voltage high current power cables from Nas Platform to elevation ring (200 ft maximum).

– Elevation ring will include two 3’x8’ thermally controlled optical benches and electronics controller. Size of this enclosure will be similar to the K2 laser enclosure on the telescope.

– Sealed systems for condensation considerations; No need for clean room.

– Will require 16KW to 20KW for power and heat removal.

• AFRL expects to complete the SOR and Maui system by 2010. • Fits into NGAO’s timeline for procurement of laser in 2010.• Possible collaboration effort

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LMCTI Feasibility

• LMCTI is focused on finishing GSK lasers.• Discussions suggest some minor reduction in size of the current

system; but not likely to be significantly different without additional funding.

• System architecture will be similar to K1 using the SLP architecture.• Will require large enclosure on or below Nasmyth Platform to house

multiple laser benches and electronics racks.

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The ‘F’ Factor

• Fiber Lasers– ESO is developing fiber laser internally and externally with manufacturer

(Volius in Moscow). 4 lasers to be installed on the VLT.

– Currently 5+Watts. Expects power to double by Jan 08.

– Once power levels are met, technology will be transferred to engineering company in Europe.

– Product will be available to all.

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WBS 3.3 Laser

• Progress– Draft Laser Architecture Report on Twiki. Needs update with recent CfAO

discussions.

– Laser Enclosure Requirements Updated

– Laser Requirements Upated.

– Block Diagram for laser control system updated. Start specifying the blocks and interfaces.