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Korobkina E, Berkutov I, Golub R, Huffman P, Hickman C, Leung K, Medlin G, Morano MJ, Rao T, Teander C, White C, Young AR. Growing solid deuterium for UCN production. JOURNAL OF NEUTRON RESEARCH 2022. [DOI: 10.3233/jnr-220010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We have experimentally studied growing a large (about 1 liter) solid ortho-deuterium crystal in a real UCN source cryostat and recorded the growing process optically using a camera. The best quality was observed when growing the crystal directly from a vapor phase. The crystal was grown at different mass flows of deuterium and annealed at different temperatures. Optimum conditions were found for both, obtaining an optically transparent crystal and cooling it down with minimal damage. We found that the quality, final shape and changes during annealing of the crystal are very much dependent on the temperature profile of the cryostat walls.
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Affiliation(s)
- Ekaterina Korobkina
- Department of Nuclear Engineering, NC State University, NC, USA
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Igor Berkutov
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Robert Golub
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Paul Huffman
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Clark Hickman
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Kent Leung
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
- Department of Physics and Astronomy, Montclair State University, NJ, USA
| | - Graham Medlin
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Matthew J. Morano
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Thomas Rao
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Cole Teander
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Christian White
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
| | - Albert R. Young
- Department of Physics, NC State University, NC, USA
- Triangle Universities Nuclear Laboratory, Durham, NC, USA
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Datta R, Chuss DT, Eimer J, Essinger-Hileman T, Gandilo NN, Helson K, Kogut AJ, Lowe L, Mirel P, Rostem K, Sagliocca M, Sponseller D, Switzer ER, Taraschi PA, Wollack EJ. Anti-reflection coated vacuum window for the Primordial Inflation Polarization ExploreR (PIPER) balloon-borne instrument. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:035111. [PMID: 33820033 DOI: 10.1063/5.0029430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/02/2021] [Indexed: 06/12/2023]
Abstract
Measuring the faint polarization signal of the cosmic microwave background (CMB) not only requires high optical throughput and instrument sensitivity but also control over systematic effects. Polarimetric cameras or receivers used in this setting often employ dielectric vacuum windows, filters, or lenses to appropriately prepare light for detection by cooled sensor arrays. These elements in the optical chain are typically designed to minimize reflective losses and hence improve sensitivity while minimizing potential imaging artifacts such as glint and ghosting. The Primordial Inflation Polarization ExploreR (PIPER) is a balloon-borne instrument designed to measure the polarization of the CMB radiation at the largest angular scales and characterize astrophysical dust foregrounds. PIPER's twin telescopes and detector systems are submerged in an open-aperture liquid helium bucket dewar. A fused-silica window anti-reflection (AR) coated with polytetrafluoroethylene is installed on the vacuum cryostat that houses the cryogenic detector arrays. Light passes from the skyward portions of the telescope to the detector arrays through this window, which utilizes an indium seal to prevent superfluid helium leaks into the vacuum cryostat volume. The AR coating implemented reduces reflections from each interface to <1% compared to ∼10% from an uncoated window surface. The AR coating procedure and room temperature optical measurements of the window are presented. The indium vacuum sealing process is also described in detail, and test results characterizing its integrity to superfluid helium leaks are provided.
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Affiliation(s)
- Rahul Datta
- Department of Physics and Astronomy, Johns Hopkins University, 3701 San Martin Drive, Baltimore, Maryland 21218, USA
| | - David T Chuss
- Department of Physics, Villanova University, 800 Lancaster Avenue, Villanova, Pennsylvania 19085, USA
| | - Joseph Eimer
- Department of Physics and Astronomy, Johns Hopkins University, 3701 San Martin Drive, Baltimore, Maryland 21218, USA
| | | | - Natalie N Gandilo
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
| | - Kyle Helson
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
| | - Alan J Kogut
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
| | - Luke Lowe
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
| | - Paul Mirel
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
| | - Karwan Rostem
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
| | - Marco Sagliocca
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
| | - Danielle Sponseller
- Department of Physics and Astronomy, Johns Hopkins University, 3701 San Martin Drive, Baltimore, Maryland 21218, USA
| | - Eric R Switzer
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
| | - Peter A Taraschi
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
| | - Edward J Wollack
- NASA Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, Maryland 20771, USA
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