CMB-S4 Concept Definition Task Force Update AAAC, NSF 2017 June 22 CMB-S4 CDT Progress Report Lawrence—1 AAAC, 22 June 2017
CMB-S4
Concept Definition Task
Force Update
AAAC, NSF
2017 June 22
CMB-S4 CDT Progress Report Lawrence—1 AAAC, 22 June 2017
Charge To the CDTExcerpt from the letter to Buell from three NSF Divisions and DOE HEP requesting theAAAC to establish “a Cosmic Microwave Background Stage 4 Concept Definition Taskforce (CMB-S4 CDT) as a subcommittee in order to develop a concept for a CMB-S4experiment”.
CMB-S4 CDT Progress Report Lawrence—2 AAAC, 22 June 2017
CDTMembers
CDT
Julian Borrill LBNLJohn Carlstrom ChicagoTom Crawford ChicagoMark Devlin PennJo Dunkley PrincetonRaphael Flauger UCSDBrenna Flaugher FNALShaul Hanany U MinnesotaKent Irwin Stanford/SLACBill Jones PrincetonBrian Keating UCSDJohn Kovac HarvardAkito Kusaka LBNLCharles Lawrence (Chair) JPLAdrian Lee Berkeley/LBNLJeff McMahon MichiganMike Niemack CornellSteve Padin ChicagoClem Pryke MinnesotaSuzanne Staggs PrincetonEd Wollack GSFC
Contacts: Kathy Turner DOERich Barvainis NSFBrian Keating AAAC
Advisory Board: Lloyd Knox UCDSarah Church StanfordAmber Miller USCLyman Page PrincetonJohn Ruhl CWRMartin White Berkeley
CMB-S4 CDT Progress Report Lawrence—3 AAAC, 22 June 2017
Introduction
• The CDT has had weekly telecons and four face-to-face meetings since
December. A final pre-report face-to-face meeting is scheduled for the
end of August.
• The Technology Book has been completed by the CMB-S4 collaboration.
It and the Science Book are both available on-line.https://arxiv.org/abs/1706.02464 http://arxiv.org/abs/1610.02743
• Initial version of science and measurement requirements completed
– Supported by new and more realistic simulations
• Synergies with other measurements/experiments have been considered
in science requirements
• Costing model well underway
• Starting to consider strawman concept options, R&D development
needed
CMB-S4 CDT Progress Report Lawrence—4 AAAC, 22 June 2017
Science — I
• Since the first detection of the CMB over 50 years ago, CMB measurements
have continuously transformed our understanding of the early universe.
• Measurements of the CMB by ground-based, balloon, and satellite
experiments have determined the age and composition of our universe,
and provide strong evidence that the seeds of structure are quantum-
mechanical.
• Observations have nearly exhausted the information accessible in
primary temperature anisotropies, but with “Stage 3” experiments,
precision measurements of polarization, lensing, and secondary effects
have just begun.
• The “Stage 4” experiment CMB-S4 is the natural next step for ground-
based CMB measurements, and will transform our understanding of the
early universe and of particle physics yet again.
CMB-S4 CDT Progress Report Lawrence—5 AAAC, 22 June 2017
Science — II: Gravitational Waves
• CMB-S4 will be exquisitely sensitive to gravitational waves at recombination.
• If observed, these gravitational waves are a pristine relic of the primordial
universe.
• In the foreseeable future, their imprint on the polarization of the CMB is
our only way to detect them.
• These gravitational waves are independent from density perturbations,
and a detection would provide a new window onto the early universe.
CMB-S4 CDT Progress Report Lawrence—6 AAAC, 22 June 2017
Science — III: Inflation 1
• Many models of inflation predict a gravitational wave signal large
enough to be detected with CMB-S4.
• According to inflation, primordial gravitational waves arose as quantum
fluctuations in the metric of spacetime.
• As a consequence, a detection of gravitational waves with CMB-S4
would provide insight into quantum gravity.
• In addition, a detection would measure the expansion rate and energy
density during inflation.
CMB-S4 CDT Progress Report Lawrence—7 AAAC, 22 June 2017
Science — III: Inflation 2
• In the absence of a detection, constraints from CMB-S4 would rule out
widely-studied classes of inflationary models.
• CMB-S4 will measure the polarization of the CMB on small scales with
unprecedented precision.
• This will reduce uncertainties on many other primordial observables (e.g.,
primordial power spectrum, non-Gaussianity, isocurvature modes) by a
factor of 2–3.
CMB-S4 CDT Progress Report Lawrence—8 AAAC, 22 June 2017
Science — IV: Light Relics
• CMB-S4 will explore and constrain a wide range of extensions of the
standard model currently explored in the particle physics community.
• Many well-motivated extensions of the standard model to higher energies
predict light, long-lived particles.
• CMB-S4 will be sensitive to light relics even if they interact too weakly to
be detected in lab-based experiments.
• CMB-S4 will provide the most robust and precise cosmological constraints
on light relics.
CMB-S4 CDT Progress Report Lawrence—9 AAAC, 22 June 2017
Science — V: Neutrinos
• Neutrinos are the least explored corner of the Standard Model of particle
physics.
• A major effort is underway to study their properties in short- and long-
baseline as well as neutrino-less double beta decay experiments.
• CMB-S4 will probe the properties of neutrinos in a way that is important
and complementary to lab-based experiments.
• CMB-S4 will provide a measurement of the sum of neutrino masses
through weak gravitational lensing of the CMB even for the minimum
mass in the normal mass hierarchy.
• CMB-S4 will independently measure the sum of neutrino masses through
cluster counts, with comparable sensitivity.
CMB-S4 CDT Progress Report Lawrence—10 AAAC, 22 June 2017
Science — VI: Evolution of Cosmic Structure
• CMB-S4 will determine the impact of feedback processes on the
distributions of dark and baryonic matter in the Universe, by measuring
the thermodynamic profiles of the ionized gas in galaxies, groups, and
clusters.
• CMB-S4 will measure the growth of cosmic structure with galaxy clusters,
enabling tests of modified gravity and dark energy in a complementary
way to LSST.
• CMB-S4 will provide a legacy-class high-z (z > 2) cluster sample that will
be the definitive target list for astrophysics studies with other experiments
(e.g., JWST, LSST, Euclid, WFIRST, Athena).
• CMB-S4 will determine the duration of reionization using the kSZ effect.
CMB-S4 CDT Progress Report Lawrence—11 AAAC, 22 June 2017
Science Goals: Design Drivers & “Free” Science
• Design drivers:
– Primordial gravitational waves and inflation
– Light relics
• “Free science”:
– Neutrino mass measurements
– Measurement of the evolution of cosmic structure
– . . .
CMB-S4 CDT Progress Report Lawrence—12 AAAC, 22 June 2017
Simulations
Science ��!Measurements ��! Hardwaresims sims
• The fidelity of the inferences depends on the fidelity of the simulations.
• We’ve worked hard on improving the fidelity of the simulations, in
particular trying to capture the real-world complexities of foregrounds
and systematic errors
– Cannot simulate either foregrounds or systematics exactly. The goal is to berepresentative.
– Sims for inflation science are map-based, to be able to represent the seriousnon-Gaussianity of foregrounds and systematics.
• Now implementing improved dust and systematic residuals
– Realistic low-frequency foregrounds still being developed
• So far, no major surprises or cliffs have been seen in more realistic sims.
CMB-S4 CDT Progress Report Lawrence—13 AAAC, 22 June 2017
Costing — I
• Approach
– Parametric model supports various experiment configurations
various telescope sizes and types
number of cameras per telescope
number of detectors at each wavelength in each camera
– Cost estimates based on
scaling from Stage-2 and 3 experiments
quotes for current projects
expert opinion
– Cost uncertainty based on
scatter between several estimates for each major component
DOE practice for contingency vs. maturity of design
• Status
– Cost models for telescopes, cryostats, and detectors are well developed. Models forpre-fabrication development, data management, the analysis pipeline, and assembly,integration, test, and commissioning are preliminary.
– Missing: pre-project R&D
CMB-S4 CDT Progress Report Lawrence—14 AAAC, 22 June 2017
Costing — II: WBS
1. Management (project manager, EVMS project controls, L2 and L3 managers,annual NSF/DOE reviews, directors reviews, etc.).Estimated as a percentage of WBS items 2–10.
2. Systems engineering
3. Chile site preparation
4. South Pole site preparation
5. Telescopes
– Large
– Small
6. Cryostats
– For large telescopes
– For small telescopes
7. Detectors and readout
8. Data acquisition
9. Data and pipeline management
10. Integration
11. Commissioning
Costs from Stage 3 projects provide thebasis of estimate for WBS items 3–8.
CMB-S4 CDT Progress Report Lawrence—15 AAAC, 22 June 2017
Costing — III: Reviews
• Ongoing internal review by CDT
• Reviews by DOE experts who are not on CDT
• September “red team” review
CMB-S4 CDT Progress Report Lawrence—16 AAAC, 22 June 2017
Report1 SCIENCE JUSTIFICATION AND GOALS 3
1.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.2 Gravitational waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.3 Inflation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.4 Light relics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.5 Neutrino masses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.6 Evolution of cosmic structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 SCIENCE REQUIREMENTS 4
3 MEASUREMENT REQUIREMENTS 4
4 INSTRUMENT DESIGN 44.1 Options and Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44.2 Heritage (Feasibility) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
5 OPERATIONS 5
6 DATA MANAGEMENT 66.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66.2 Instrument Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66.3 Time Domain Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66.4 Science Exploitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76.5 Simulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76.6 Publication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
7 COLLABORATION STRUCTURE 7
8 COMPLEMENTARITY WITH MEASUREMENTS FROM SPACE 7
9 TECHNOLOGY DEVELOPMENT 89.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89.2 Technological Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.2.1 Telescopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89.2.2 Receiver Optics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89.2.3 Focal-Plane Optical Coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . 89.2.4 Focal-Plane Sensors and Readout . . . . . . . . . . . . . . . . . . . . . . . . . 89.2.5 Receiver Cryogenics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99.2.6 Instrumental Control and Monitoring . . . . . . . . . . . . . . . . . . . . . . . 99.2.7 Calibration and Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
9.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
10 STAGING AND SCHEDULE 9
11 COST 911.1 Basis of Estimate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
A Simulations and instrumental details 9
B Comparison with previous (Stage 3) experiments 9
2CMB-S4 CDT Progress Report Lawrence—17 AAAC, 22 June 2017
Major Design Features• CMB-S4 will be a single experiment and collaboration
• Two sites: South Pole and Atacama– South Pole has the best atmospheric conditions of any developed site
– Atacama is also an excellent site and is needed to get to fsky = 0.4
CMB-S4 CDT Progress Report Lawrence—18 AAAC, 22 June 2017
Sky Coverage
– Low foreground regions - inflation and lensing
– Overlap with optical surveys —- combine with LSS measurements for neutrinos,dark energy, dark matter, and astrophysics.
CMB-S4 CDT Progress Report Lawrence—19 AAAC, 22 June 2017
The End
• We have a settled structure for the science and measurement requirements
– Numbers are still tentative
– Simulations are iterating to higher levels of realism
• We will have the final report in October, as promised!
CMB-S4 CDT Progress Report Lawrence—20 AAAC, 22 June 2017