cmb-s4 technology development — progress since the harvard ... · 05.03.2018 · cmb-s4...

CMB-S4 Technology Development —progress since the Harvard workshop: Input to CDT

Zeeshan AhmedMarch 5, 2017

CMB-S4 Workshop, ANL, March 2018

Zeeshan Ahmed CMB-S4 workshop, ANL, March 2018

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In August 2017 at the end of the workshop..

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• Identified that next steps after Technology book were:• A CMB-S4 development (R&D) program with priorities

• Feeding this as input to the agencies to guide their decisions about how to fund pre-project development

• Due ~now to feed into FY20 budget process

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• We decided to start a community process for assessing our technology development priorities

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• In parallel, the CDT was charged with developing the straw person concept for CMB-S4, and also assess and provide technology development priorities to the agencies

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• In parallel, the CDT was charged with developing the straw person concept for CMB-S4, and also assess and provide technology development priorities to the agencies

• In parallel parallel, CMB scientists from ANL, FNAL, LBNL and SLAC were working to assess, prioritize and synergies their own activities to best serve CMB-S4 development

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What happened next..

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• The CDT had an earlier deadline (October 2017)• Community process was slowly getting under way

• DOE Labs process had made some progress

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• The CDT asked the DOE labs to help with technology development prioritization

• Brad Benson and I took on the challenge of coming up with a prioritized R&D plan backed with some quantitative assessment.

• Provide this to the CDT to assess and decide what they agreed with and formally recommend in their report.

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• The CDT asked the DOE labs to help with technology development prioritization

• Brad Benson and I took on the challenge of coming up with a prioritized R&D plan backed with some quantitative assessment.

• Provide this to the CDT to assess and decide what they agreed with and formally recommend in their report.

• Note that this was part of the CDT mandate, and was a separate assessment from the community process.

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Input from CDT costing external reviewers..

• CDT Costing Review Committee (M. ’Gil’ Gilchriese et al) recommendations:

• “Estimate risk-based contingency using a high level risk registry. Identify technical risks that could be retired by the R&D program.”

• “Develop an R&D plan that is consistent with CD-1 and CD-2 milestones and the timescale of the decadal survey that has well defined deliverables and demonstrates critical risk reduction. Coordinate funding for this R&D plan with DOE and NSF.”

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Analysis scheme we used

• Took CDT straw person as our reference (Detector counts, # of cameras etc). Added a few details to fill in blanks as necessary

• Used LSST-like risk & opportunity evaluation scheme (Help from Nadine Kurita, former LSST-Cam project manager)

• Covered many areas of the project (Detectors, Readout, Data Pipeline, Cryostats, Optics, Telescopes)

• Technology agnostic!

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Total Impact = (0.33 x Cost Impact) + (0.33 x Schedule Impact) + (0.33 x Science Impact)

CMB-S4 Risk Registry V7.xlsm 3. Risk Analysis Methodology Page 1 of 1

Risk Score Risk Level5 5 10 15 20 25 Critical4 4 8 12 16 20 High3 3 6 9 12 15 Moderate2 2 4 6 8 10 Minor1 1 2 3 4 5 Insignificant

1 2 3 4 5Impact Probability

Tota

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pact

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Sample of this assessment (~40 items total)

> 3 month delay in critical path

Primary science impacted

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Sample of Top Risks shared with CDT

Risk Title Current Exposure

Integrated FP Performance (end-to-end) 23.3 Critical

Array production 23.3 Critical

MUX factor, noise, stability 19.2 High

Testbeds for readout and detectors 18.3 High

Sensor Performance 16.7 High

MUX integration yield 16.7 High

Wafer Fabrication Yield 16.0 High

Simulation framework maturity 16.0 High


Summary of CMB-S4 Project Risks Across Subsystems

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Sub-System Highest Risk in Subsystem Mitigation

Readout Integrated Performance (MUX factor, Noise)

Develop multiple readout technologies with orthogonal technical risks and downselect.

Detectors Array Production Develop and validate processes, yield, and throughput at multiple fabs.

Data Management Simulations Develop simulation framework to evaluate instrument designs and systematics.

Optics Half-wave plate, AR coating ETU of half-wave plate and anti-reflection coating.

Cryostat Complexity, Cryogenics Stage-3 prototypes, early design and procurement.

Telescope Ground pickup Insufficient ground shielding causes significant systematic uncertainty.

Critical Risk High Risk Moderate Risk Minor Risk Insignificant

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Example of Development plan for Integrated Detector/Readout performance

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2017 2018 2019 2020 2021 2022 2023 2024

Cold MUX Prototype (Demonstrate MUX factor & Noise) • Pursue at least two MUX technologies with orthogonal risks. Demonstrate required MUX factor to reduce risk to conceptual design. (CMB-005). 1.5 years

• Detector fab effort to support readout development & testing.

CD-0NSF CoDr NSF PDR

CD-1 Alternatives CD-3 Start

Fiscal Years

Readout Performance, Schedule & Cost Risk – Initial Assessment • Integrated MUX and FP risks

Cold MUX + Warm Electronics • Build prototype electronics • Integrated testing of the two MUX technologies & electronics to

demonstrate noise and stability by CD-1 (CMB-027 & 028) 1.5 years

Wafers + Cold MUX + warm electronics •End-to-end testing to down-select technology by CD-2 (CMB-15) 1.5 year

•Demonstrate resonator and SQUID yield, MUX integration yield (CMB-014,007,006)

CD-2 Baseline

Decadal SubmissionNSF FDR

MREFC Approval


Transition to community evaluation• CDT used the global conclusions of this work in their report

• Next step, community evaluation • Rely on community input to flesh this out in further detail

• Make adjustments to metrics as necessary

• Consider a combination of risk and opportunities more broadly

• Expect global conclusions to be similar

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Table 3: Assessment of most significant project risks across subsystems. Risks are ordered from highest (top) tolowest (bottom). Pre-project investment is prioritized by risk and schedule.

Subsystem Risk Mitigation

Readout . . . . . . . . . . . . . . Integrated performance (MUX fac-tor, noise)

Develop multiple readout technologieswith orthogonal technical risks, anddownselect.

Detectors . . . . . . . . . . . . . Array production Develop and validate processes, yield, andthroughput at multiple fabs.

Data management . . . . . . Simulations, especially those basedon time-ordered data.

Develop simulation framework to evaluate in-strument designs and systematics.

Optics . . . . . . . . . . . . . . . Half-wave plates and anti-reflectioncoatings

Demonstrate ETU of half-save plate and anti-reflection coating.

Cryostats . . . . . . . . . . . . . Complexity, cryogenics Build Stage-3 prototypes; execute early de-signs and procurement.

Telescopes . . . . . . . . . . . . Ground pickup Early design and analysis of ground shields.

As part of a risk-assessment exercise, the top project risks were identified across subsystems.These are shown in order of decreasing risk in Table 3, along with research items to mitigate therisks. The prioritized plan for pre-project investment was developed to mitigate project risks atthe appropriate times, given the severity of the risk and the anticipated schedule of the straw-person instrument configuration. The associated e↵ort over a two-year period is 4, 4, 4, 2 full-timeequivalents (FTEs) per year for scientists, engineers, postdocs, and technicians, respectively, forreadout, 2, 2, 2, 2 for detectors, 1, 1, 3, 1 for testing, and 1, 1, 2, 0 for the development of a simulationframework. The cost of these investments is described in § 11. Further design studies and systemsengineering work will also be needed to optimize technological choices in terms of performance,schedule, and cost.

In summary, CMB-S4 will require a large increase in the number of detectors and associatedreadout components and camera optical elements as compared to Stage-3 experiments, so improvingreliability and throughput is important. Technology development should be targeted to mitigatecost, schedule, and performance risk, as well as to exploit opportunities to reduce cost. The programof investment in the pre-project period described in this section is budgeted in § 11, with detailsprovided in Appendix B.

10 STAGING AND SCHEDULE

Although the science goals of CMB-S4 are signficantly broader in scope than any of the existingCMB experiment teams have attempted to meet, many of the technical challenges for CMB-S4 areones of scale: fabricating and testing hundreds of thousands of detectors; building large cryostats;fielding multiple cameras and telescopes at two remote sites; and collecting and analyzing massiveamounts of data in multiple survey regions with multiple frequency bands. Happily, the formationof the CMB-S4 collaboration from a half-dozen or more experiment teams with many years of fieldexperience, largely from universities, with a growing influx of DOE lab researchers with extensiveexperience with large projects, means those challenges can be addressed with parallel e↵orts. Thus,the project schedule for CMB-S4 can be short, seven years from start of project (CD0) to the startof operations (CD4).

The CMB-S4 project could start immediately. A project start (CD0) in 2019 with construction(CD3) three years later has been suggested. The CDT supports and recommends this timeline.Project start in 2019 is also aligned with the ongoing Stage-3 experimental e↵orts. They have re-cently completed or will soon complete their construction phases, so resources regarding personnel

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cmb-s4 technology development — progress since the harvard ... · 05.03.2018 · cmb-s4...

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