Key R&D Activities for the LSST Camera

DOE HEP Program ReviewJune 13, 2007

Kirk Gilmore (SLAC)

LSST Camera Manager

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BrandeisJ. Bensiger, K. Hashemi, H. WellensteinBrookhaven National LabS. Aronson, C. Buttehorn, J. Frank, J. Haggerty, P. Kuczewski, M. May, P. O’Connor, V. Radeka, P. TakacsFlorida StateH. WahlHarvard UniversityN. Felt, J. Geary (CfA), J. Oliver, C. StubbsLawrence Livermore National LabS. Asztalos, K. Baker, L. Hale, S. Olivier, D. Phillion, L. Seppala, W. Wistler

Oak Ridge National Laboratory P. Stankus, G. Young, V. Cianciolo,

C. Britton (joint faculty UT) N. Ericson (joint faculty UT)Ohio State UniversityK. Honscheid, R. Hughes, B. WinerPurdueI. Shipsey, J. PetersonRochester Institute of TechnologyD. Figer

Stanford Linear Accelerator CenterG. Bowden, P. Burchat (Stanford), D. Burke, M. Foss, K. Gilmore, G. Guiffre, M. Huffer, S. Kahn (Stanford), P. Kim, T. Lavine, S. Marshall, M. Nordby, M. Perl, L. Price, A. Rasmussen, D. Rich, R. Schindler, L. Simms (Stanford), T. Weber

University of California, Berkeley

J.G. Jernigan

University of California, Davis

P. Gee, A. Tyson

University of California, Irvine

D. Kirkby

University of California, Santa Cruz

T. Schalk

University of Illinois, Urbana-Champaign

J. Thaler

University of Pennsylvania

M. Newcomer, R. Van Berg

University of Washington

L. Rosenberg

University of Tennessee

B. Blalock, R. Chun

Wayne State

D. Cinabro

LSST Camera Team Members

DoE HEP Program ReviewJune 13, 2007 3

Camera R&D Overview• Detector requirements: Detector requirements: ((Radeka/Geary - BNL/SAO))

– 10 10 m pixel size Pixel full-well > 90,000 em pixel size Pixel full-well > 90,000 e– – High QE 400 – 1000 nm High QE 400 – 1000 nm– Low noise (< 5 eLow noise (< 5 e–– rms), fast (< 2 sec) readout, stable T (-90 C) rms), fast (< 2 sec) readout, stable T (-90 C)

• Package large number of detectors, with integrated readout electronics, Package large number of detectors, with integrated readout electronics, with high fill factor and serviceable design with high fill factor and serviceable design (O’Connor/Oliver - BNL/Harvard)

• Sensor and focal plane precision alignment/stabilility/motion controlSensor and focal plane precision alignment/stabilility/motion control Sensor flatness 5u p-v, focal plane flatness 10u p-v Sensor flatness 5u p-v, focal plane flatness 10u p-v ((Takacs/Rasmussen/Schindler - BNL/SLAC/SLAC))

• Cryostat contamination control -Cryostat contamination control - (Schindler - SLAC)(Schindler - SLAC)

• Fabricate large diameter (75cm) filters with uniform coatings Fabricate large diameter (75cm) filters with uniform coatings ((Olivier - LLNL))

• Data Acquisition/ Camera Control ProtocolData Acquisition/ Camera Control Protocol - - ( (Schalk - UCSC))

• Constrained volume (camera in beam) Constrained volume (camera in beam) ((Nordby - SLAC))–Makes shutter, filter exchange mechanisms challengingMakes shutter, filter exchange mechanisms challenging

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Camera: International R&D ContributionsFilter mechanism:M. Nordby (SLAC)The LPNHE team is taking responsibility of studying and prototyping ... P. Antilogus (LPNHE) will act as contact scientist and G. Daubard (LPNHE) as technical contact.

Shutter Development:M. Nordby (SLAC)Bonn Group is studying Gordon Bowden (SLAC) design. Dialog between Bonn and SLAC started.Klaus Reif of the University of Bonn is main contact and head of shutter group

Filter development:K. Gilmore (SLAC)LSST is currently looking for qualified vendors to evaluate filters.R. Pain (LPNHE) and the LPNHE/Lyon teams will help coordinate SAGEM evaluation

Analog signal processing ASIC:J. Oliver (Harvard)A joint LAL+LPNHE team will take responsibility of prototyping the FE ASIC.P. Antilogus (LPNHE) will act as contact scientist and V. Tocut (LAL) as technical contact.

Software slow control:T. Schalk (SLAC/UCSC)The IN2P3 groups will evaluate a possible contribution in the control software and hardware of the camera. P. Antilogus (LPNHE) will act as contact for this effort.

Instrumental calibration:D. Burke (SLAC):The LPNHE group will participate in the definition of an instrumental calibration strategy for LSST.P. Astier (LPNHE) will act as contact scientist for this effort.

DoE HEP Program ReviewJune 13, 2007 5

Sensor Fabrication and Delivery Schedule_______________________________________________

• Contracts with four vendors for study phase • Goals:

– technology development leading to back-illuminated sensors with thick, fully depleted substrate and transparent conductive window– large-format, small pixels Schedule– flat, 4-side-buttable package 1. Study - Jan06-Feb07 2. Prototype - Jul07-Aug09 3. Production - Oct09-Sep12

Risks

1. CCD performance2. Mulit-port R.O.3. Flatness4. Packaging

DoE HEP Program ReviewJune 13, 2007 6

Shutter Reliability_______________________________________________

- Required cycle life is long- Belt-drive system could behave

differently depending on orientation- Blade dynamics could be an issue at

high-speed- Wear and near-constant motion could

produce particulates that wouldcontaminate L3 lens and filters

Shutter Assembly Closed

Motors with 3 drive pulleys of different diameters

Shutter Assembly Open

Drive rail contains ball-roller track with 6 carriages for each of the blades

Blades are contoured to fit around convex crown of L3 to save Z-space

Blades stack beyond field of view when not in use

Guide rail channel tracks cam followers in blades to reduce sagging of blades

DoE HEP Program ReviewJune 13, 2007 7

Filter Fabrication_______________________________________________

R&D: Coating of large filters requires large coating facilities with precision process controls to meet LSST filter coating specs.

0.0

20.0

40.0

60.0

80.0

100.0

300 400 500 600 700 800 900 1000 1100 1200

Wavelength (nm)

Tra

nsm

issi

on

u g r i z Y

DoE HEP Program ReviewJune 13, 2007 8

Electronics Packaging in a Constrained Volume

_______________________________________________

The Raft-Tower is comprised of sensors, structures requiring precise alignment, and high-density front-end electronics boards.

Raft TowerRaft TowerFront-side

View

FEE Boards

Raft

Flex cables and Thermal Straps

Front-end ASIC

DoE HEP Program ReviewJune 13, 2007 9

DAQ/CCS Communications Protocol R&D

• Determine functionality of controls and data acquisition

• Prototype test stand to establishcommunication configuration

• Prototype system to facilitate sensor and raft development

OCS

SAS SDS FCS

DM

MCM

DAQ Client interface

Subsystem modules

Control interface

CCS

Controls Architecture

Controls Reference Design Subsystems

Science Array (SAS)Data Acquisition (SDS)Wavefront Sensor (WFS)Wavefront Data Acquisition (WDS)Guide Sensor (GSS)Guide Sensor Data Acquisition, Analysis (GAS)Focal Plane Actuation Unit (FPU)Shutter Controller Unit (SCU)Filter Controller (FCS)Thermal Control (THC)Vacuum Control (VCS)Power and Signal Controller Unit (PSU)

DoE HEP Program ReviewJune 13, 2007 10

Filter Exchange Mechanism R&D

Prototype Questions• Five filters just fit in the

camera• Double-rail mechanism

could bind in operation• Clamps and locking pins

could fail

Filter Changer and Carousel Assemblies

Rails and ball screw provide linear actuationYoke

Linkage converts linear actuation to follow filter path

Double-rail provides X, Z, and tilt motion of filter

Filter clamp into base cradles

Carousel ring bearing mounts to back flange