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Title: Final Report: Advanced Detector Technologies for Precision Measurement of Inflation, Dark Energy, and Neutrino Masses with the Cosmic Microwave Background

Technical Report ·
DOI:https://doi.org/10.2172/1460362· OSTI ID:1460362
 [1]
  1. Univ. of Michigan, Ann Arbor, MI (United States)

Precision measurements of the Cosmic Microwave Background (CMB) provide unparalleled op- portunities to probe the conditions in the early universe and thereby explore particle physics and gravity at the highest energies yet; measure the number of neutrino species and the sum of the neutrino masses with sensitivity beyond what is achievable with planned terrestrial experiments; improve our knowledge of dark energy; and search for other forms of new physics. The P-5 panel recognized the importance and potential of future CMB observations and recommended the DOE fund a stage four CMB experiment (CMB-S4) under all budget scenarios with construction commencing near the end of this decade. The objective of this proposal is to develop and demonstrate new technologies in time to maximize the science return of CMB-S4. The proposed technologies include: (i) broad band metamaterial antireflection coatings on relevant lenses with negligible absorptive and reflective losses; (ii) filters that reduce out of band optical loading with near perfect in band transmission; (iii) broad-band continuously spinning metamaterial half wave plates that boost the sensitivity to inflationary gravitational waves on large angular scales and mitigate systematics with minimal penalty to the instantaneous sensitivity; and (iv) broad band detectors that will enable excellent foreground discrimination while simultaneously maximizing the sensitivity to the signals from inflation and neutrinos. Together these technologies can realize significant improvements in instrumental sensitivity and control of systematic effects. This improvement in raw sensitivity could be used to reduce costs without sacrificing science by deploying a smaller number of more sensitive detectors, or to improve the sensitivity of CMB-S4 to physics parameters including reducing the error bar on r by the inverse of the mapping speed improvement. Beyond raw sensitivity these technologies address key systematics including polarization mixing and galactic foregrounds and enable CMB-S4 to test the shape of the polarization power spectrum out to larger angular scales further boosting measurements of inflation. In this report we detail the progress that has been made in these technical areas. This includes: (i) a demonstration of 4:1 bandwidth AR coating technology and a detailed understanding of the production challenges, (ii) prototype filters that incorporate absorptive and reflective components into silicon, (iii) a prototype broad band HWP fabricated from metamaterial silicon, and (iv) detector designs spanning 20-350 GHz with an understanding of the difficulties associated with bandwidths greater than one octave.

Research Organization:
Univ. of Michigan, Ann Arbor, MI (United States)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP)
DOE Contract Number:
SC0015799
OSTI ID:
1460362
Report Number(s):
DOE-UniversityofMichigan-SC0015799; TRN: US1901681
Country of Publication:
United States
Language:
English

References (2)

Pushing the Limits of Broadband and High-Frequency Metamaterial Silicon Antireflection Coatings journal May 2018
Composite reflective/absorptive IR-blocking filters embedded in metamaterial antireflection-coated silicon journal January 2017