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Improving ultracold neutron intensities for frontier precision experiments in fundamental physics

English title Improving ultracold neutron intensities for frontier precision experiments in fundamental physics
Applicant Lauss Bernhard
Number 163413
Funding scheme Project funding (Div. I-III)
Research institution Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Particle Physics
Start/End 01.11.2015 - 31.10.2019
Approved amount 403'153.00
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All Disciplines (2)

Discipline
Particle Physics
Other disciplines of Physics

Keywords (4)

ultracold neutron production ; search for physics beyond the standard model; fundamental neutron physics; ultracold neutron

Lay Summary (German)

Lead
Verbesserung der Intensitäten von ultrakalten Neutronen für Experimente an den Grenzen der Grundlagenphysik.Am Paul Scherrer Institut (PSI) wurde in jüngster Zeit eine neue hochintensive Quelle für ultrakalte Neutronen (UCN) gebaut und in Betrieb genommen. Damit will man höchste UCN Intensitäten erzeugen, welche modernste Grundlagenforschung mit Neutronen ermöglicht und ein weltweit führendes Benutzerinstrument in der Schweiz etabliert.
Lay summary

Ultrakalte Neutronen haben so geringe Energien (im nano-Elektron-Volt Bereich), dass sie, im Gegensatz zu schnelleren Neutronen, unter allen Einfallswinkeln von speziellen Materialien reflektieren.  Solche geringen Energien entsprechen Temperaturen nahe dem absoluten Nullpunkt, daher der Name "ultrakalt".

UCN können daher in speziellen, evakuierten Behältern lange (einige Minuten) beobachtet werden und dadurch können ihre Eigenschaften sehr genau bestimmt werden. Man kann zum Beispiel ihre Lebensdauer präzise vermessen oder nach einem möglichen elektrischen Dipolmoment des Neutrons (nEDM) suchen. Beide Experiemente arbeiten mit hoher Präzision und viele Neutronen müssen genau beobachtet werden.  Die Lebensdauer des Neutrons erlaubt Aussagen über die unterschiedliche Verteilung der leichten Elemente nach dem Urknall. Die Suche nach dem nEDM hilft beim Verständnis von der grossen Asymmetrie von Materie und Antimaterie im Universum.

Das Forschungsprojekt hat zur Aufgabe die Intensität der UCN an der weltweit führenden Quelle des PSI zu verbessern und dadurch die Sensititvität der Grundlagenexperimente stark zu verbessern. Die beabsichtigten Arbeiten inkludieren ein besseres Verständnis der Produktion der UCN, welche im Festdeuterium bei 5 Grad über dem absoluten Nullpunkt stattfindet, sowohl mittels neuen Messungen als auch mittels Simulationen. Zusätzlich wird eine neue Anlage für die Produktion von verbesserten Neutronenleiter geplant. Diese sind sehr dünn beschichtete Glasrohre, welche die UCN von der Produktion bis zum Experiment leiten.
Direct link to Lay Summary Last update: 07.10.2015

Responsible applicant and co-applicants

Employees

Publications

Publication
PicoTesla absolute field readings with a hybrid 3He/87Rb magnetometer
Abel Christopher, Bison Georg, Griffith W. Clark, Heil Werner, Kirch Klaus, Koch Hans-Christian, Lauss Bernhard, Mtchedlishvili Alexander, Pototschnig Martin, Schmidt-Wellenburg Philipp, Schnabel Allard, Pais Duarte, Voigt Jens (2019), PicoTesla absolute field readings with a hybrid 3He/87Rb magnetometer, in The European Physical Journal D, 73(7), 150-150.
Magnetic-field uniformity in neutron electric-dipole-moment experiments
Abel C., Ayres N. J., Baker T., Ban G., Bison G., Bodek K., Bondar V., Crawford C. B., Chiu P.-J., Chanel E., Chowdhuri Z., Daum M., Dechenaux B., Emmenegger S., Ferraris-Bouchez L., Flaux P., Geltenbort P., Green K., Griffith W. C., van der Grinten M., Harris P. G., Henneck R., Hild N., Iaydjiev P., et al. (2019), Magnetic-field uniformity in neutron electric-dipole-moment experiments, in Physical Review A, 99(4), 042112-042112.
The ultracold neutron source at the Paul Scherrer Institute – Performance and status
Anghel A., Bison G., Blau B., Daum M., Hild N., Kirch K., Lauss Bernhard, Ries D., Schmidt-Wellenburg P., Talanov V., Wohlmuther M., Zsigmond G. (2019), The ultracold neutron source at the Paul Scherrer Institute – Performance and status, in Journal of Neutron Research, 20(4), 83-86.
Solid deuterium surface degradation at ultracold neutron sources
Anghel A., Bailey T. L., Bison G., Blau B., Broussard L. J., Clayton S. M., Cude-Woods C., Daum M., Hawari A., Hild N., Huffman P., Ito T. M., Kirch K., Korobkina E., Lauss B., Leung K., Lutz E. M., Makela M., Medlin G., Morris C. L., Pattie R. W., Ries D., Saunders A., Schmidt-Wellenburg P., et al. (2018), Solid deuterium surface degradation at ultracold neutron sources, in The European Physical Journal A, 54(9), 148-148.
Demonstration of sensitivity increase in mercury free-spin-precession magnetometers due to laser-based readout for neutron electric dipole moment searches
Ban G., Bison G., Bodek K., Daum M., Fertl M., Franke B., Grujić Z.D., Heil W., Horras M., Kasprzak M., Kermaidic Y., Kirch K., Koch H.-C., Komposch S., Kozela A., Krempel J., Lauss B., Lefort T., Mtchedlishvili A., Pignol G., Piegsa F.M., Prashanth P., Quéméner G., Rawlik M., et al. (2018), Demonstration of sensitivity increase in mercury free-spin-precession magnetometers due to laser-based readout for neutron electric dipole moment searches, in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detector, 896, 129-138.
Search for Axionlike Dark Matter through Nuclear Spin Precession in Electric and Magnetic Fields
Abel C., Ayres N. J., Ban G., Bison G., Bodek K., Bondar V., Daum M., Fairbairn M., Flambaum V. V., Geltenbort P., Green K., Griffith W. C., van der Grinten M., Grujić Z. D., Harris P. G., Hild N., Iaydjiev P., Ivanov S. N., Kasprzak M., Kermaidic Y., Kirch K., Koch H.-C., Komposch S., Koss P. A., et al. (2017), Search for Axionlike Dark Matter through Nuclear Spin Precession in Electric and Magnetic Fields, in Physical Review X, 7(4), 041034-041034.
Losses and depolarization of ultracold neutrons on neutron guide and storage materials
Bondar V., Chesnevskaya S., Daum M., Franke B., Geltenbort P., Göltl L., Gutsmiedl E., Karch J., Kasprzak M., Kessler G., Kirch K., Koch H.-C., Kraft A., Lauer T., Lauss B., Pierre E., Pignol G., Reggiani D., Schmidt-Wellenburg P., Sobolev Yu., Zechlau T., Zsigmond G. (2017), Losses and depolarization of ultracold neutrons on neutron guide and storage materials, in Physical Review C, 96(3), 035205-035205.
Comparison of ultracold neutron sources for fundamental physics measurements
Bison G., Daum M., Kirch K., Lauss B., Ries D., Schmidt-Wellenburg P., Zsigmond G., Brenner T., Geltenbort P., Jenke T., Zimmer O., Beck M., Heil W., Kahlenberg J., Karch J., Ross K., Eberhardt K., Geppert C., Karpuk S., Reich T., Siemensen C., Sobolev Y., Trautmann N. (2017), Comparison of ultracold neutron sources for fundamental physics measurements, in Physical Review C, 95(4), 045503-045503.
Ultracold neutron detection with 6Li-doped glass scintillatorsNANOSC: A fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute
Ban G., Bison G., Bodek K., Chowdhuri Z., Geltenbort P., Griffith W. C., Hélaine V., Henneck R., Kasprzak M., Kermaidic Y., Kirch K., Komposch S., Koss P. A., Kozela A., Krempel J., Lauss B., Lefort T., Lemière Y., Mtchedlishvili A., Musgrave M., Naviliat-Cuncic O., Piegsa F. M., Pierre E., Pignol G., et al. (2016), Ultracold neutron detection with 6Li-doped glass scintillatorsNANOSC: A fast ultracold neutron detector for the nEDM experiment at the Paul Scherrer Institute, in The European Physical Journal A, 52(10), 326-326.
An ultracold neutron storage bottle for UCN density measurements
Bison G., Burri F., Daum M., Kirch K., Krempel J., Lauss B., Meier M., Ries D., Schmidt-Wellenburg P., Zsigmond G. (2016), An ultracold neutron storage bottle for UCN density measurements, in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detector, 830, 449-453.
A prestorage method to measure neutron transmission of ultracold neutron guides
Blau B., Daum M., Fertl M., Geltenbort P., Göltl L., Henneck R., Kirch K., Knecht A., Lauss B., Schmidt-Wellenburg P., Zsigmond G. (2016), A prestorage method to measure neutron transmission of ultracold neutron guides, in Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detector, 807, 30-40.
Revised experimental upper limit on the electric dipole moment of the neutron
Pendlebury J. M., Afach S., Ayres N. J., Baker C. A., Ban G., Bison G., Bodek K., Burghoff M., Geltenbort P., Green K., Griffith W. C., van der Grinten M., Grujić Z. D., Harris P. G., Hélaine V., Iaydjiev P., Ivanov S. N., Kasprzak M., Kermaidic Y., Kirch K., Koch H.-C., Komposch S., Kozela A., Krempel J., et al. (2015), Revised experimental upper limit on the electric dipole moment of the neutron, in Physical Review D, 92(9), 092003-092003.
Observation of Gravitationally Induced Vertical Striation of Polarized Ultracold Neutrons by Spin-Echo Spectroscopy
Afach S., Ayres N. J., Ban G., Bison G., Bodek K., Chowdhuri Z., Daum M., Fertl M., Franke B., Griffith W. C., Grujić Z. D., Harris P. G., Heil W., Hélaine V., Kasprzak M., Kermaidic Y., Kirch K., Knowles P., Koch H.-C., Komposch S., Kozela A., Krempel J., Lauss B., Lefort T., et al. (2015), Observation of Gravitationally Induced Vertical Striation of Polarized Ultracold Neutrons by Spin-Echo Spectroscopy, in Physical Review Letters, 115(16), 162502-162502.
Gravitational depolarization of ultracold neutrons: Comparison with data
Afach S., Ayres N. J., Baker C. A., Ban G., Bison G., Bodek K., Fertl M., Franke B., Geltenbort P., Green K., Griffith W. C., van der Grinten M., Grujić Z. D., Harris P. G., Heil W., Hélaine V., Iaydjiev P., Ivanov S. N., Kasprzak M., Kermaidic Y., Kirch K., Koch H.-C., Komposch S., Kozela A., et al. (2015), Gravitational depolarization of ultracold neutrons: Comparison with data, in Physical Review D, 92(5), 052008-052008.

Collaboration

Group / person Country
Types of collaboration
Prof. G. Ban , Laboratoire de Physique Corpusculaire, Caen France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Tritiumlabor KIT KArlsruhe Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
Prof. N. Severijns, Katholieke Universiteit, Leuven Belgium (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Prof. K. Bodek, Jagellonian University, Cracow Poland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Prof. W. Heil, Institut fuer Physik, Gutenberg Universitaet Mainz Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Max Doebeli / ETH Zuerich - Ion Beam Laboratory Switzerland (Europe)
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Efficient Neutron Sources Talk given at a conference The solid-deuterium-moderator-based ultracold neutron source at PSI 02.09.2019 Villigen PSI, Switzerland Lauss Bernhard;
Theoretical issues and experimental opportunities in searches for time reversal invariance violation using neutrons Talk given at a conference Searching for a neutron electric dipole moment - European efforts 06.12.2018 Amherst - University of Massachusetts, United States of America Lauss Bernhard;
PTB Colloquium Individual talk "Searching for a neutron electric dipole moment by spin precession of ultracold neutrons 21.11.2018 PTB Berlin, Germany Lauss Bernhard;
SPS Annual Meeting Talk given at a conference Investigating the Solid Deuterium in the PSI UCN Source Moderator 28.08.2018 Lausanne, Switzerland Hild Nicolas;
5th International Workshop on Neutron Delivery Systems Talk given at a conference The ultracold neutron source at the Paul Scherrer Institute - Performance and Statu 25.06.2018 Grrenoble, France Lauss Bernhard;
International Workshop on Particle Physics at Neutron Sources 2018 Poster The new apparatus for an increased sensitivity search for the neutron EDM at the PSI ultracold neutron source 24.05.2018 Grenoble, France Lauss Bernhard;
International Workshop on Particle Physics at Neutron Sources 2018 Poster Investigating the Solid Deuterium in the PSI UCN Source Moderator 23.05.2018 Grenoble, France Hild Nicolas;
Investigating the Solid Deuterium in the PSI UCN Source Moderator Talk given at a conference Investigating the Solid Deuterium in the PSI UCN Source Moderator 08.03.2018 Zurich, Switzerland Hild Nicolas;
nEDM 2017 Talk given at a conference The next phase of the search for a neutron electric dipole moment at the Paul Scherrer Institute - Status of n2EDM 15.10.2017 Harrison Hot Springs , Canada Lauss Bernhard; Ries Dieter; Zsigmond Geza;
SPS Annual Meeting Talk given at a conference Investigating the Solid Deuterium in the PSI UCN Source Moderator 21.08.2017 Genf, Switzerland Hild Nicolas;
Physics of Fundamental Symmetries and Interactions - PSI2016 Poster Status of the PSI UCN Source 16.10.2016 Villigen PSI, Switzerland Hild Nicolas;
International Nuclear Physics Conference - INPC2016 Talk given at a conference The ultracold neutron facility for fundamental physics and the high-sensitivity search for an electric dipole moment of the neutron at the Paul Scherrer Institute 11.09.2016 Adelaide, Australia Lauss Bernhard;
SPS Annual Meeting Poster Monitoring of the ortho-D2, tritium and HD concentrations in the moderator deuterium of the PSI UCN source 23.08.2016 Lugano, Switzerland Hild Nicolas;
7th international symposium and school for young scientist ' Modern problems of Laser Physics' Talk given at a conference Atomic magnetometry for the neutron electric dipole moment experiment at Paul Scherrer Institut 22.08.2016 Novosibirsk, Russia Koch Hans-Christian;
International Workshop: Probing Fundamental Symmetries and Interactions with UCN Talk given at a conference The ultracold neutron facility at the Paul Scherrer Institute 11.04.2016 Mainz, Germany Lauss Bernhard;
International Workshop: Probing Fundamental Symmetries and Interactions with UCN Talk given at a conference Sources for ultracold neutrons: a world-wide comparison 11.04.2016 Mainz, Germany Ries Dieter;


Self-organised

Title Date Place
NuMu2019 Workshop 25.10.2019 Villigen PSI, Switzerland
EQLIPS Workshop 25.10.2019 Villigen PSI, Switzerland
Workshop on muonic atom spectroscopy 25.10.2016 Villigen PSI, Switzerland

Associated projects

Number Title Start Funding scheme
188700 A new search for an electric dipole moment of the neutron with increased sensitivity and an improved UCN source. 01.09.2020 Project funding (Div. I-III)
178951 A novel neutronics model of the solid D2 ultracold neutron converter at PSI aiming for increasing the source intensity 01.07.2018 Project funding (Div. I-III)
150651 A mobile Raman spectrometer to determine the spin population of deuterium gas 01.12.2013 R'EQUIP
157079 Search for the neutron EDM at the high intensity ultracold neutron source at PSI with an upgraded high sensitivity spectrometer - Follow-up application II. 01.10.2014 Project funding (Div. I-III)
169596 Spin-spectroscopy with ultracold neutrons - Searching for dark matter and lorentz violation using spin-precessing neutrons 01.09.2017 Project funding (Div. I-III)
177008 Field Generation and Control System for the n2EDM spectrometer 01.12.2017 R'EQUIP
172639 Precision Physics with Muons and Ultracold Neutrons 01.05.2017 Project funding (Div. I-III)
186179 n2EDM: The next measurement of the neutron electric dipole moment 01.04.2019 FLARE
149813 Pushing the high intensity frontier with ultracold neutrons 01.11.2013 Project funding (Div. I-III)
144473 Search for the neutron EDM at the high intensity ultracold neutron source at PSI with an upgraded high sensitivity spectrometer - Follow-up application 01.10.2012 Project funding (Div. I-III)
117696 The PSI polarized ultracold neutron source: optimization and first test measurements 01.02.2008 Project funding (Div. I-III)
137664 Pushing the high intensity frontier for ultracold neutrons 01.11.2011 Project funding (Div. I-III)

Abstract

This new proposal, consisting of a Ph.D. and a post-doc research program, aims at unprecedented world-record intensities of ultracold neutrons (UCN). The new-generation spallation-based ultracold neutron source at PSI is a facility in regular operation. The design goal at PSI is to surpass UCN sources available in the last decades by a factor of 10 - 100 in UCN intensity. Such UCN intensities are required by sensitive frontier precision experiments in fundamental physics, most prominently the search for a permanent electric dipole moment of the neutron and other precision experiments to search for physics beyond the Standard Model of Particle Physics or dark matter. Our suggested research topics build upon research conducted under longstanding SNF support and will also benefit from equipment recently purchased with R’EQUIP support. The requested Ph.D. project is presently staffed with Dieter Ries who is scheduled to finish by May 2016.The Ph.D. project’s research is focused on the characterization and understanding of UCN production and delivery. The main questions to be answered are centered on the neutronics behavior of the source and its unique 5 kg solid deuterium at 5 K. Does one correctly understand the neutrons’ cold moderation in D2 ? We suggest to develop a new calibration method for tritium in D2 gas to validate the cold moderation model and to calibrate the tritium measurements using accelerator mass spectroscopy. Can one understand the major UCN losses occurring inside the bulk solid deuterium with its many imperfections and cracks, or are surface characteristics dominant ? What is the role of elemental and isotopic impurities ? What is the behavior of the molecular spincomponents under irradiation ? How can we influence the solid deuterium growth and the surface conditions ?The Ph.D. project’s main emphasis is on planning, conducting, analyzing and publishing the related measurements which will be conducted within the UCN source setup and also using specialized external setups. The answers to these questions will provide strong indications where and how one can realize increases to the UCN intensity. The post-doctoral researcher will support and complement all the above listed student’s research activities. The postdoc will in close cooperation with Dr. Geza Zsigmond optimize the existing advanced Monte Carlo (MC) simulation of the full UCN source and produce a comprehensive study of all characterization measurements and their MC description which will further guide the improvement project. In addition a main focus will lie on technical developments which aim at higher UCN intensities. Most important will be the development of a new coating facility for large-sized glass tubes which will be directly reflected in the larger delivered UCN intensity. In parallel the post-doc will conduct investigations towards improved UCN coatings with high material optical potential (e.g. isotopically pure elements), low surface losses and low neutron depolarization. Various test-methods to check successful coatings are available at PSI. In order to reduce transmission losses a search for improved structural materials will be conducted via UCN transmission measurements of selected materials. New designs for various components of the UCN source will be investigated via detailed simulations of the entire neutron and UCN production. The study will include post-production neutron optics, different designs of solid D2 containers, moderator and reflector lay-out and UCN guides.Both, Post-Doc and Ph.D. researchers, will work closely together to proceed with our international project of benchmarking UCN facilities. We have started a pilot measurement with one simple storage vessel. Comparison measurements at PSI and at all worldwide operating UCN facilities are planned in the near future. The project of this proposal is expected to continue beyond 2018. Both, Ph.D. and post-doc will be working within the UCN physics group at PSI. Ph.D. supervisor will be Dr. Bernhard Lauss (PSI), assisted by Dr. Geza Zsigmond. The academic supervisor will be Prof.Dr. Klaus Kirch at ETH Zürich.
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