Shield Group Plans

1
Shield Group Plans

• SNAP Introduction (Science Satellite)
• Present Scope of the Shield Group Work
• Work Plans for FY04 FY05
• Physicists Engineers
• Budget Request for FY04 (SKIP this part?)

Tom Diehl 10/01/2003
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Cosmology and Type 1a SN

• Detect SN w/ 0.3 lt z lt 1.7 in multiple filter
  bands (0.35 to 1.7 microns).
• Peak luminosity to 2 (stat.) or better through
  multiple measurements over the light curve.
• Spectographic observations near peak intensity
• Measure host galaxy redshifts
• Identify and analyze 2000 branch normal Type
  1a supernovae to produce redshift vs. distance
  curve.

From S.P. 7/9/2
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Wide-Field Survey

• SNAP Plans
• The SN survey is narrow and deep 15 deg.2. SNAP
  also plans for 300 (some of our EAG guys are
  pushing for 1000 deg.2)
• Measure weak-lensing of distant galaxy clusters
  from intervening dark matter.
• More

HST image with SNAP resolution. (Annis et al.
SNAP WAS on web)
4
SPACECRAFT CONFIGURATION
Secondary Mirror Hexapod and Lampshade Light
Baffle
Door Assembly
Main Baffle Assembly
Secondary Metering Structure
Primary Solar Array
Primary Mirror
Optical Bench
Solar Array, Dark-Side
Instrument Metering Structure
Instrument Radiator
Tertiary Mirror
Fold-Flat Mirror
Instrument Bay
Spacecraft
Shutter
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Shield Components and Electronics

• The shield consists of a conical object 2/3m
  tall 2/3 meter wide.
• Multi Purpose
• Ionizing radiation
• Thermal Isolation of detector
• Block or absorb stray light

Focal plane CCD Readout electronics Spectrograph M
ass storage
All material is potentially shielding
6
Cone Shield (Mar. 2003)

• text

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Present Scope of the Shield Group Work

• Instrument package must be shielded against
• stray optical light, thermal hotspots, and
  ionizing radiation
• Instruments that have requested shielding and
  calculations
• Focal plane
• Spectograph
• Readout electronics (back of focal plane)
• Mass memory
• Fermilab should take responsibility for the
  physics calculations, design, and possibly
  fabrication of the shields
• Physics involves understanding the components of
  the Cosmic Rays, simulating the effects on the
  detect using MARS/GEANT, and optimizing the
  shield design (trades between effectiveness,
  material, and weight).
• Engineering Design involves optimization for
  mechanical and thermal stability, integration
  into the spacecraft, etc
• Of course, these are coupled.

Based on 03/2003 SNAP Collaboration Meeting and
subsequent trip report (4/4/3)
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Physics Work in FY04 Strategy

• Concentrate on the MARS effort at first
• Produce a standard set of cosmic ray source files
  (useful for either MARS or GEANT)
• Model the satellite and instrument components
  (think shielding material and detector)
• Optimize the shield design
• Progress as of Aug. 20, 2003
• Cosmic Ray Sources a good start
• Satellite model is crude
• Instruments model is undeveloped

We are making progress on all of these
things.
Be reminded that SNAP is thinking about using
thinner ccds because of the cosmic ray
background and that our simulations might be
helpful there, as well.
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Almost Preliminary Results Using MARS
Cosmic Ray Sources
Creme96 Spenvis Proton spectrum matches AMS
data in higher energy range
From TM-2221 Draft By Rakhno, Mokhov, and
Striganov, Peterson
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Physics Work in FY04 Goals

• Finalize the Cosmic Ray Sources
• Satellite Model should be recognizable and
  approximate the major materials. Instrument
  package modeled in some detail.
• We should have specs for the electronics in the
  instruments.
• We should have made first estimates of the
  radiation doses in the instruments.

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Physics Work in FY05 Strategy Goals

• In FY05 we should be working on a full detector
  simulation that allows us to provide a catalog of
  cosmic ray images for timed exposures in the CCD
  and spectrograph
• Wed like to provide MC cosmic ray images that
  can be combined with MC images of observables.

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Engineering Work in FY04

• To do this job right requires (vetted by Jim
  Kerby)
• 1/4 to ½ FTE in support of the physics work
• ½ to 1 FTE of finite element structural modeling
• ½ to 1 FTE thermal analysis and integration (I
  suppose this could include optical reflections
  shielding on the inside surface of the cone, as
  well).
• ½ FTE planning design verification test venue,
  apparatus, instrumentation
• 1 FTE coordinating, communicating with Pankow,
  Lafever et al., bringing in outside designs and
  design concepts
• Sum is 0.5 to 4.0 FTEs
• Require Drafters/Detailers at about 25 once we
  are past 1 FTE.
• Require technician effort at 0.5 FTE level.

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Engineering Request in FY04

• At present we have ¼ FTE engineering. We should
  have 4 FTE working on it within a year.
• As a practical matter we will have ¼ FTE at
  beginning FY04.
• An engineer costs about 120,000 salary and
  benefits (J.K.).
• 0.5 FTE is 60,000. 4.0 FTE is 480,000.
• One of myriad realistic turn-on curves is
  linear growth in engineering effort.
• Wed like to be at 4.0 FTE by the end of 04.
• 270,000 for engineers (0.5 1/21.75 FTE)
• Plus 280,0000.25 for designer/draftspeople
• Plus 25,000 for technicians
• Total for salaries and benefits is 365,000.

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Engineering Work in FY05

• Assumption is that we stay within scope
• We could possibly do more once we are doing the
  shielding work well
• One more FTE working on test apparatus
• Significant drafting and tech. labor will require
  more supervisory/management time from the lead
  engineer.

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Scope Planning Contingencies

• In order for this effort to grow past ¼ FTE (the
  minimum for supporting the shielding calculation)
  some things must happen
• It can be done for pay. But, the engineers must
  receive a clear and visible signal from the
  divisions it is permissible to work on SNAP. The
  attraction is there. Engineers capable of
  performing the jobs are interested.
• The extent to which we are involved in the
  engineering depends on our communications with
  LBL and the greater SNAP community.
• We have to establish good lines of communication
  in order to be effective.
• This suggests an initial push on travel.
• Peter Limon is drafting the integrated request
  document.

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Travel etc Total for FY04

• 365,000 for salaries and benefits (assuming
  120,000 per engineer)
• 30,000 for travel (25 trips to LBL at 1,000 per
  plus 5,000 more)
• 10,000 for engineering software. I dont know
  what it is yet.
• 2,000 for one computer.
• 1,000 for books and technical manuals
• 12,000 for test venue and samples.

Total 420,000
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Summary

• SNAP is great science and interesting as physics
  and engineering problem.
• I found (03/2003) that SNAP leadership seems
  willing to let us be responsible for as much as
  we want w.r.t shielding.
• Shield subgroup physics effort seems on track for
  accomplishing FY04 goals and has nice plans for
  beyond that.
• We have listed what engineering we need to
  accomplish scope of work involved in shielding
• Requires permission to work on SNAP.
• Effective communication with LBL at the
  engineering level.
• Shielding subgroup FY04 Budget request is
  420,000.

John Marriner pointed out that we have a budget
code and a line in the effort report sheet, so it
can be worked-on by the engineers.