lbt adaptive optics - arcetri › ~salinari › feb_2004_board › lbt... · 2004-02-25 ·...

LBT Board 27 Feb. 2004 P.Salinari LBT AS&AO 1

LBT Adaptive Secondaries

andAdaptive Optics

Status reportFor the February 2004

Board Meeting


Introduction

The reference AO document remains:“LBT Adaptive Optics System: status and perspectives”(Report to the LBT Board, P. Salinari, January 18th 2002, on the Board web pages)Although many details have changed, the current activity is in excellentAgreement with the above general plan.

This was followed by regular:• Reports to SAC on Adaptive Secondary and Adaptive Optics • Design reviews with participation of LBT PO staff


Who does what for the AS?

AS electronics AS mechanics

Arcetri

AS SWand test

Arcetri

AO WFSAO SW

AGW

Mirrors and back platesThe interaction in Arcetri between AS and WFS is strong

- the WFS hosts diagnostic and maintenance tools of the AS

- both use each other for full AO system test

The interaction in Arcetri between AS and WFS is strong

- the WFS hosts diagnostic and maintenance tools of the AS

- both use each other for full AO system test


People currently involved in AS construction

LBT Project OfficeJ. Hill

G. BrusaJ. Brinnel

P. Salinari

R. Biasi

M. Andrighettoni

D.Veronese

W. Ponzo

D. Gallieni

A. Ripamonti

E. Anaclerio

D. Acerboni

B. Martin

S. Miller

+++

Arcetri

Coordinator: A. Riccardi

C. Del Vecchio

A. Puglisi

P. Ranfagni

P. Stefanini

M. Xompero


LBT Adaptive Secondary milestones

Past Milestones • 1992 decision to (try to) go for Adaptive Secondaries• 2001 LBT AS concept defined: 672 actuators• 2002 MMT336 goes on the telescope• 2002 contracts for design of LBT672, prototype (P45) and optics• 2003 P45 delivered to Arcetri• 2003 contract for construction of 2xLBT672• 2003 final design review• 2003 ok for mass production of mechanicsFuture Milestones•2004 March delivery of first back plate•2004 April ok for mass production of electronics•2004 June delivery of first thin mirror•2004 October delivery of AS1 unit to Arcetri•2005 January Shipment to Mt Graham


AS+AO cost and relevant contracts

AS + AO Cost

•2002 AO 013: P45 Microgate+ADS ~0.4 M$•2002 AO 014: Optics Mirror Lab ~1.0 M$•2003 AO 017 2xLBT672 Microgate+ADS ~1.8 M€• AO ??? SW+Test Arcetri ~0.4 M€• AO ??? W+AO-SW Arcetri ~0.7 M€

Contracts Total (for two units, assuming1 M€ ~ 1.25 M$) ~ 5.0 M$

Missing item: Spare thin mirror (<500 k$)


MMT-LBT AS specifications . . .

480 Mmac/s (32 bit floating)40 Mmac/s (16 bit integer)DSP

400 Mbit/sNo dedicatedEffective Diag. Comm. BW

4 Gbit/s (peak)160 Mbit/sEffective RT Comm. BW

2.4 W/act (t = 1.6 mm)4.7 W/actPower (crate level)

0.26 W/act (t = 1.6 mm)0.41 W/actPower (act level)

0.5 N/W1/20.5 N/W1/2Act efficency

64 nm72 nmFitting error

672336N act

911 mm / 1.6 mm641 mm / 2 mmDiameter / Thickness

LBTMMTr0=15cm@500nm

i.e.: entirely new electronicsi.e.: entirely new electronics


. . . and other differences (dictated by MMT experience)

MMT336 Problem LBT672 SolutionCoolant leaks ⇒ New cooling circuitDust in the gap ⇒ Thicker gap (new control system!)Actuator spikes ⇒ New actuators, Gold contactsCable chaos ⇒ Distribution boardsTelescope vibrations ⇒ Provision for accelerometer loop

+Separate diagnostic communicationFully remote SW-FirmW maintenance Safer mirror support (power off condition)

We only have adaptive secondaries on the telescope:

highest priority isReliability & Maintainability


Where are we now with the P45 tests?

240mm, 45 actuators

MMT electronics + LBT components• New magnets: OK• New actuator mechanics: OK• New connections: OK• New cooling system: OK• New capacitive sensors: OK• New Au coating: OK• New derivative control: very OK!• New software: OK• New “fff” mirror: very OK!With final LBT electronics• Refine test of new electronics• Refine test of new control With W unit• Full AO test in closed loop

Most of the new features are already well tested. The remaining ones (new electronic boards) are already partly tested.

Most of the new features are already well tested. The remaining ones (new electronic boards) are already partly tested.


P45 mirror modes(it means that the new hardware and the new control work)


An important new step: Digital Damping

Gap=67µmGprop = 0.1N/µmGderiv = 25Ns/mDnatural = 17Ns/m

Settling time: 0.7ms


The new LBT electronic boards exist and work

• Microgate BCU board:– HD complete and functioning

for months with W – 3 units built for P45– low level SW 95% (high speed communication implementation is close tocompletion)

• Microgate DSP board – HD complete and functioning– 10 units built for P45– low level software ~100%(all basic algorithms implemented)


More boards . . .

Signal Generator board:(6 needed for each AS)

10 DSP boards for P45 (84 for eachAS)DSP test board

Test board designed to perform a fully automated test and characterization of the DSP board analog interfaces

Burn-in test board

This board has been developed to provide a 'dummy load' for the DSP boards during system 'burn-in' test


Production ofactuators Magnets

Coils

Cold fingers (1300)


Production of “back” and “cold” plates

The Zerodur backplate@ Mirrorlab is now close to delivery(second week of March?)

The blanks of the two cold plates(pre-machining should start next week)


Test Tower nearly ready


Adaptive Secondary summary

Positive aspects• Most technical changes wrt MMT are now tested and work well• The design goals appear to be well within reach• Construction of components progresses regularly• No significant cost overrun is expected

Negative aspects• The delivery date shifted in one year from late 2004 to early 2005 (mainly due to delayed back plate delivery)

I believe we are now walking on a very solid ground.I believe we are now walking on a very solid ground.


Comparison of AO systems

LBT 1stLight AO (30x30,672)

Number of WFS subapertures

Num

ber

of a

ctua

tors

Keck (20x20,349)

NAOS/VLT(14x14,185)

ALTAIR/Gemini (12x12,177)

Subaru (36,36)SINFONI-MACAO/VLT (60,60)

Moreover:

• “pyramid gain”(~ one magnitude)

• 1kHz rate at full WFS resolution


W, what is it?

•It is the Single Conjugate, Natural Star AO System (WFS+control)for the bent Gregorian foci, (W part of AGW). Foreseen upgrades are:üuse of a Sodium artificial starüuse of LLLCCD with natural starsüuse as WFS unit for LBTI

•It includes:üall the necessary “AO supervisor” softwareüthe AS+W test and calibration equipmentüan optical “technical viewer” (provided by Arcetri)

•It features:üan achromatic double-Pyramidüvariable modulation (gain) and pupil samplingüatmospheric dispersion compensator (ADC, 0 –70 deg ZA)

Still, it is very compact and cheap, thanks to the Adaptive Secondary


W unit of AGW

Finding Chartfor the W unit in the AGW(seen from mirror side)


People involved

AGW coordinator:

J. Storm+++

Arcetri

W

coordinator:

S.Esposito

M. Carbillet

D. Ferruzzi

L. Fini

A. Puglisi

P. Stefanini

A. Tozzi


W Milestones

Past Milestones •2001 New conceptual design based on Pyramid is approved•2002 Preliminary design•2002 Final design. Procurement of components starts.•2003 Prototype ready•2004 Start of integration of first telescope unit

Future Milestones•2004 March Start procurement for second unit •2004 April Integration test in AGW unit (Potsdam)•2004 June Loop closed with P45 (final AS electronics)•2004 October Integration in test tower with LBT672•2005 January Shipment to Mt Graham with LBT672


The Prototype W

W Prototype

Telescope simulator

Wavefront computer(Microgate BCU)

The Prototype W is now working for several months using • a BCU board as (final) slope computer

and (provisional) wavefront reconstructor

• final optomechanical components including the E2V 39 detector.

The telescope simulator includes a commercial wavefrontcorrector (OKO, 37 elements) replacing the secondary, sothat the entire system (HD and SW) has been tested in closed loop. In early summer 2004 the OKO will be replaced by P45 with its final electronics. The final W unit will then be used in late 2004 with the real adaptive secondary.


The telescope unitFinal (anodized) optics mountsbeeing installed on final plate(still to be anodized).(Optics and detectors are still mounted in the prototype)


Pyramid

The first high qualityachromatic “double pyramid”was produced at Arcetri a fewmonths ago.With < 5 µm rounded edgereaches a (measured) optical efficiency of ~ 95% with diffraction limited image size (no modulation, ? 632,8 nm, F/45)

Procuring good quality pyramids had been a worry for a long time.


Old and new pyramid

Pupil images on the test CCD(As showed at SAC June 2003)

Pupil images on the WFS CCDusing double pyramid(Dec2003)

Pupil images are now uniformly illuminated and of nominal size (30 pix)


Communication scheme (partly implemented in the lab)

Supervisor


The supervisor software and its GUI (mostly implemented)


W Summary

Positive aspects• Most HW ans SW aspects are now well tested on the prototype unit• The design goals appear to be well within reach• Construction of first telescope unit in progress (ready in April)• No significant cost overrun is expected

Negative aspects• The delivery date is linked to that of the secondary and is therefore

shifted to early 2005 (but the second unit could be sent earlier withthe first AGW, if necessary, for AGW telescope integration and preliminary test)

Again, we seem to walk on solid ground.Again, we seem to walk on solid ground.

lbt adaptive optics - arcetri › ~salinari › feb_2004_board › lbt... · 2004-02-25 ·...

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