IMACS progress report no. 37

B. Bigelow						7 May 2001

	Project Status

Currently scheduled tasks:				Status:

a)	Disperser server (DSS) design (Bond)		done
b)	DSS drafting (Cleary)				IP
c)	DSS fabrication (Kowal)				IP
d)	SCAM filter server (Asa)			IP
e)	Field lens mechanics fab (Hare)			done
f)	Calibration system mech. des. (Hare)		delayed
g)	Mask server integration (Asa)			late (90% compl.)
h1)	Coll. fabrication (Danco)			done, but not to spec.
h2)	Coll. fab (M&T)					starts in May 
i)	Coll. opto-mech assembly (Bigelow)		late start (June?)
j)	Long camera drafting (Cleary)			done
k)	Long camera fabrication (Bigelow)		on sched.
l)	Center Field Guider mechanics fab (Storts)	late
m)	CF Guider assy (Asa)				delayed by CFG fab
n)	Principal Guider Camera fab (Storts)		delayed by CFG fab
o)	Science Array controller fab (Burley)		95% compl.
p)	Short Camera mech. design (Bigelow)		on sched.
q)	Filter procurement (Sutin)			on sched.
r)	Grism procurement (Sutin)			on sched.
s)	Motion control (MC) electr. design (Carr)	late (70% compl.)
t)	MC fab. (Asa)	    				late (50% compl.)
u)	Control software design (Birk)			on sched.


Project events:

1)  Final dewar parts received from GL Scientific, waiting for final
    drawing package
2)  S. Gunnels started the IMACS structure design in April

Latest construction images can be seen on the IMACS web site:

http://www.ociw.edu/instrumentation/imacs


	Optics (Sutin) 

1) We have given up on dielectric coatings for the field lens, and
   are going with Sol-Gel.  The field lens has been shipped to
   Cleveland Crystal for Sol-Gel coating.  The Sol-Gel throughput
   dove-tails nicely with the Newport coatings.

2) C02 and C03 are coated and here at OCIW.  The coatings are okay
   except for a big bump (2% - 2.5%) at 0.54 microns.  This is the
   Sol-Gel minimum, however.  C02 has a chip at the edge, and we
   have to decide if we want to have it polished, and who should
   do that.

3) L06 is finished at TORC.  L04 is still being worked.  The problem
   is that the lens is so thin in the middle that it is very difficult
   to get a perfect figure on both sides at once.  I told TORC to
   get the air side good, and let the figure on the oil side go
   ("go" here means a mere 1/4 wave...).

4) TORC is generating (shaping) the material for the short camera.

5) Still no word from REOSC.

6) Spectrum has their new, amazing, and wonderful ion source.  They
   are having the set of usual initial-installation-of-high-tech-
   gadgetry installation problems, but the source works spectacularly,
   and he expects that he should be able to produce coatings both
   harder and with better performance than Coherent.

   My assessment of the SESO coatings is that they used high index
   absorptive materials to achieve a flat AR response, at the expense
   of throughput.  The total loss averaged 2.75% on their proposed
   coating.  In contrast, the Newport coatings are all fluorides, with
   negligible absorption.

7) The center-field Shack-Hartman fold mirrors (I am having two
   made in different sizes) have been sent to Newport for over-coated
   Aluminum.

8) I finally prodded the Fabry-Perot science crowd into motion,
   and it looks like a proposal for $$$ may appear.  If funded,
   we may have an etalon to deliver along with the instrument.


	Electronics (Asa/Carr)

Asa:

Accomplished in April:

- Filter server 1 and 2 disassembled, and ready for modifications and
  anodizing.
- Slit Mask server electronics tested: Everything has been tested and
  shown to work by Christoph except for the indexer near and limit 
  switches which have not been tested yet.
- Drawings for electronic chassis 2 through 4 have been completed and
  given to Vince.
- Drawings for translation and stop mechanisms for the center field
  guide camera have been completed and given to Robert.

Things to do in May:

- Build control electronics for center field guide camera.
- Test Shutter.
- Complete testing of slit mask server.

Carr:

In April I delivered the Disperser Server design, however details for
the sensors, motors & encoders are missing. I think Joe can place
orders for cables, connectors, chassis, etc. but wiring should be held
off till Tim chooses sensors, motors and encoders. I will need to
revise the drawings at that time.

I also worked with Christoph on the Mask Server. The encoder seems to
have a bad index output. I would like to have Joe take a look at the
encoder to verify my findings.

Next month I would like to work on the Grating tilt mechanisms. 

	Software (Birk/Clardy)

Birk:

Done in April:

- The slit-mask server is up and running. The encoder is
  working in non-differential mode only and needs to be 
  repaired. We also need a new position sensor for the
  insert-solenoid and different mounting for the hard-limits.

Planned for May:

- long-term testing of slit-mask server
- test shutter with magnets (vertical move) and verify timing
- science array software

Clardy:

No report.

	Detector Systems (Thomson/Burley)

Guider and Science Cameras:

For April:

We recruited Jorge Estrada, he has started building guider boards with
a goal of completing 20 cameras in total. He will assemble cameras to
take the guider CCD's that we have in hand, then move on to assembling
science boards.

Science Cameras:

We completed the science camera electronics, integrating the entire
package with the engineering grade CCD, pumped and cooled. Debugging
suggested some minor modifications (revised analog switch pull-ups on
clock driver board, adjusted power supply trimming to allow for
voltage drops in filters). There is no pattern noise when any of the
DC voltages are used as input to the preamplifier. The noise is 2.0 DN
with the input grounded. Greg wrote code to read and interpret the
signal from the temperature sensor, this sensor tracks a diode sensor
well.

Cool-down time was 8 hours with the CCD installed to an operating
temperature of -100 C (compared to about 3.5 hours without the
CCD). We plan to change the gas in the cryotiger to one with a much
higher pumping capacity, we'll also need to trim the cold strap from
the CCD to the dewar cold surface.

The setup CCD gives a video signal, but does not image. All of the
clocks and DC voltages are correct on the CCD itself, the parallel
clocks seem not to be connected on the CCD.

The A/D chips get hot, but the temperature can be managed with passive
heat sinks. A fan system might be needed for the IMACS saddlebag. The
shop is making the heat sinks.

Greg also designed a small PCB to clean up the temperature sensor and
heater resistor wiring on the back of the CCD boat. The design
drawings for the boats are in error (the holes to attach to the CCD
are incorrect), all of the boats will need (very) minor modifications.

We've asked NOAO to send over the last of our 12 CCD in the joint SITe
order, and have asked if they have an engineering chip that images
that we could borrow for a short time.

For May:

Start profiling the CCD's and testing them in the lab dewar.  Modify
the DSP code to allow easy adjustment of the clock and DC
voltages. Teach Jorge how to assemble guider cameras.

A question of interest is how we are going to allocate the SITe CCD's.
At the moment, we expect delivery of the first red sensitive Lincoln
Labs chips in May or June. As a result, we will hold off assembling a
dewar for MIKE using the SITe chips, the first science camera to be
assembled will now likely be the 4Kx4K camera. This will help us
understand how to put together a science array camera.

Schedules: Greg is back in Pasadena on May 2 (Vancouver), Ian on May 7
(Las Campanas).

	Mechanics (Bigelow/Bond/Hare)

Bigelow:

In April:

1) Collimator barrel and spacers received from Danco (San jose)
2) New, elastomeric cells for collimator designed (following fab 
   failure of flexure cells at Danco), drafting started
3) LCAM fabrication contract let to Martinez & Turek, parts due 6/18/01
4) Revised dynamic image motion error budgets (for structure design)
5) SCAM design on schedule, but likely to slip starting by end of May

In May:

1) Bruce and Alan to revise collimator and LCAM schedules
2) Complete coll. cells drafting, let fab to M & T
3) Complete baffle designs for collimator and LCAM
4) Complete alignment tooling and parts order for coll and LCAM
5) SCAM detail design of cells
6) Prepare for mask cutter system fab contract in June

Bond:

April was spent doing the following:

1) Getting a drawing package together for the remaining disperser
tilt mechanism components (that we are sending to outside shops). The
assembly/weldment drawings are still being drafted.

2) Getting parts lists together for all remaining disperser server
system components. This includes tilt mechanisms and carousel purchase
parts.

3) Finishing details of the carousel system (ie. changes to the cable
wrap size and support pillar details)

May will be spent on the following....

1) finishing up the above items

2) completing documentation for the assembly of the disperser server
system.

3) reviewing details of the disperser mechanism with Tyson/Bruce.

4) FEA analysis and summary of the grating flexural performance.

Hare:

April:

* Continuing with revisions of guide camera solid models and part drawings.
* Reviewing status of electronics for guide cameras.
* Field Lens RFQ.
* Continued work with IMACS structure solid model.
* Compiling necessary documentation for Field Lens Assembly RFQ.

May:

* Minor rework of parts for shutter.
* Continue revisions to guide camera solid models and part drawings as needed.
* Let contract for Field Lens Assembly fabrication.
* Examine tooling setup for Field Lens from coating process (Cleveland Crystal)
* Resume design work of the Calibration Unit.
* Begin review of Disperser Server design.

	Fabrication (Kowal/Storts)

Kowal:

April's Report:

1) A machinist has been found and a job offer was sent out to him yesterday.  
2) Completed 2mm and 4mm stencils for guider.
3) The trunion has been machined through the first operation and has
   been sent out to TCI precision for waterjet machining.
4) Grating flexures will be started by end of the day.
5) Pilar is making pillars. These are for the grating flexure.
6) Pilar has light-weighted filter server base plates. There was a
   mistake made on two of the plates. Once corrected both filter
   servers may be sent out to anodize.

Expectation's for May:

1) Working with new machinist and getting him situation. 
2) Finish programming rest of Grating Tilt Mechanism parts.


8)     Other Business

Next meeting:  10:15, 5/30/2001