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Pushing the high intensity frontier for ultracold neutrons

English title Pushing the high intensity frontier for ultracold neutrons
Applicant Lauss Bernhard
Number 137664
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 01.11.2011 - 31.10.2013
Approved amount 141'988.00
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All Disciplines (2)

Discipline
Particle Physics
Other disciplines of Physics

Keywords (1)

ultracold neutrons

Lay Summary (English)

Lead
The new high intensity ultacold neutron source at the Paul Scherrer Institut will allow very sensitive measurements which will contribute to a better understanding of particle physics and the matter-antimatter asymmetry in our universe.
Lay summary

At the Paul Scherrer Institute a new, high intensity source of ultracold neutrons (UCN) has been built with the goal to do experiments for the study of fundamental properties of the neutron, e.g. to search for a possible electric dipole moment of the neutron (nEDM) or to precisely determine the neutron lifetime. The outcome of these experiments may have far-reaching consequences for the standard model of particle physics, new ideas going beyond that, and also for big-bang nucleosynthesis. The project aims firstly at optimizing the overall performance of the UCN source with respect to the intensity of  ultracold neutrons - unpolarized and polarized - delivered to experiments based on a solid understanding of the source via detailed simulation of UCN production and the neutron flight path from production to detection. Corresponding measurements of the UCN source parameters (like total intensity or flux, energy spectrum) will on one side help in the development of the model but on the other side help to deliver optimized operation parameters which are crucial information for the operating staff and the experimentators.

Additionally, we will develop a coating facility which aims at optimizing various surfaces for UCN performance via hydrogen-free diamond-like carbon (DLC) coatings. Based on the vacuum-arc technique we want to develop high density coatings with a high diamond-like (sp3) molecular bonding.

As third part we want to study the systematic influence of UCN source performance on experiments, e.g. the nEDM experiment, which area crucial to reach the final sensitivity goal of the experiment.

Direct link to Lay Summary Last update: 21.11.2012

Responsible applicant and co-applicants

Employees

Publications

Publication
An endoscopic detector for ultracold neutrons
Goeltl L., Chowduri Z., Fertl. M., Grey F., Henneck R., Kirch K., Lauss B., Lefort T., Mtchedlishvili A., Schmidt-Wellenburg P., Zsigmnod G. (2013), An endoscopic detector for ultracold neutrons, in Euro. Phys. J A, 49, 9.
The ultra-cold neutron source at PSI
L. Goeltl (2013), The ultra-cold neutron source at PSI, in Tenth International Topical Meeting on Nuclear Applications of Accelerators 2011 (AccApp’11), Knoxville, TN, USA.
A New Facility for Fundamental Particle Physics: The High-Intensity Ultracold Neutron Source at the Paul Scherrer Institute
Lauss B (2012), A New Facility for Fundamental Particle Physics: The High-Intensity Ultracold Neutron Source at the Paul Scherrer Institute, in PANIC 2011, Boston 1441, 1441.
Startup of the high-intensity ultracold neutron source at the Paul Scherrer Institute
Lauss Bernhard (2012), Startup of the high-intensity ultracold neutron source at the Paul Scherrer Institute, in EXA2011, Vienna, Austria.
Commissioning of the new high-intensity ultracold neutron source at the Paul Scherrer Institut
Lauss B (2011), Commissioning of the new high-intensity ultracold neutron source at the Paul Scherrer Institut, in INPC2012, Vancouver, Canada 312, 312.
First observation of trapped high-field seeking ultracold neutron spin states
Daum M, Fierlinger P, Franke B, Geltenbort P, Goeltl L, Gutsmiedl E, Karch J, Kessler G, Kirch K, Koch HC, Kraft A, Lauer T, Lauss B, Pierre E, Pignol G, Reggiani D, Schmidt-Wellenburg P, Sobolev Y, Zechlau T, Zsigmond G (2011), First observation of trapped high-field seeking ultracold neutron spin states, in PHYSICS LETTERS B, 704(5), 456-460.

Collaboration

Group / person Country
Types of collaboration
LPC, Laboratoire de Physique Corpusculaire, CAEN France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
JUC, Jagellonian University, Cracow Poland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
ETH Zuerich Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Joint SPS OePG Annual Meeting Talk given at a conference 05.09.2013 Linz, Austria Lauss Bernhard; Ries Dieter;
ESS Science Symposium on Neutron Particle Physics Talk given at a conference 25.03.2013 Grenoble, France Kirch Klaus; Lauss Bernhard;
CHIPP Winter School 2013 Talk given at a conference 20.01.2013 Grindelwald, Switzerland Ries Dieter;
Workshop on Neutron EDM Experimental Techniques Talk given at a conference 11.10.2012 OakRidge, USA, United States of America Schmidt-Wellenburg Philipp; Lauss Bernhard;
Zurich PhD Student Seminar Talk given at a conference 27.08.2012 Zurich, Switzerland Kirch Klaus; Göltl Leonard;
Tagung der schweizerischen Physikalischen Gesellschaft Talk given at a conference 21.06.2012 Zuerich, Switzerland Ries Dieter;
5th International Symposium on Symmetries in Subatomic Physic Talk given at a conference 18.06.2012 Groningen, Netherlands, Netherlands Lauss Bernhard;


Self-organised

Title Date Place
International Workshop, Fundamental Symmetries and Interactions, PSI2013 09.09.2013 Paul Scherrer Institue, Switzerland
nEDM Collaboration Meeting - Cracov 30.06.2013 Cracov, Poland
nEDM Collaboration Meeting at PSI 03.09.2012 Paul Scherrer Institute, Switzerland
nEDM Collaboration Meeting - KUL 05.01.2012 Leuven, Belgium

Associated projects

Number Title Start Funding scheme
150651 A mobile Raman spectrometer to determine the spin population of deuterium gas 01.12.2013 R'EQUIP
149813 Pushing the high intensity frontier with ultracold neutrons 01.11.2013 Project funding (Div. I-III)
162574 Measurement of the neutron electric dipole moment 01.11.2015 Project funding (Div. I-III)
126562 Search for the neutron EDM at the high intensity ultracold neutron source at PSI with an upgraded high sensitivity spectrometer 01.10.2009 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)
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)
139140 Passive magnetic shield for the new neutron electric dipole moment experiment n2EDM 01.01.2013 R'EQUIP
149211 Measurement of the neutron electric dipole moment 01.11.2013 Project funding (Div. I-III)
163413 Improving ultracold neutron intensities for frontier precision experiments in fundamental physics 01.11.2015 Project funding (Div. I-III)

Abstract

The new high-intensity ultracold neutron (UCN) source at the Paul Scherrer Institute (PSI) had its first successful beam operation in late December 2010. This is the first new-generation UCN source to come online with the goal of improving UCN densities available to experiments by about 2 orders of magnitude. The production of high (polarized) ultracold neutron densities is the key element for several experiments to either test the Standard Model (SM) of particle physics or predictions beyond the SM (e.g. Supersymmetry). This is most prominently represented by the search for the electric dipole moment of the neutron (nEDM) and the neutron lifetime measurement. Within the context of the UCN physics research at PSI we propose two PhD projects which aim at providing a world record UCN and polarized UCN density and study the influence of the UCN beam characteristics on the systematics of experiments, of e.g. the nEDM experiment at PSI.PhD project 1 aims at the characterization and optimization of the overall UCN source performance. Most important is the study and optimization of UCN production depending on the crystallization of the solid deuterium UCN converter, which is for the first time possible for such a large crystal. Important ingredient for a quantitative understanding and optimization is the detailed simulation of the entire source with respect to solid deuterium parameters and UCN neutronics. In Part 2 of this thesis the development of a dedicated high quality diamond-like carbon (DLC) coating facility based on vacuum-arc technique is foreseen. Highest quality DLC coatings are not yet available for relevant large surface areas or inside glass tubes. Compared to present surfaces they have a higher Fermi potential and a lower neutron loss- and depolarization rate. Part 3 aims at studying the influence of the UCN beam intensity on the systematics of the nEDM experiment, where accurate UCN intensity monitoring is necessary. PhD project 2 centers on the polarized UCN performance. It aims at delivering the highest possible polarized UCN density to experiments and additional control of the velocities of the delivered UCN. Part 1 of this work is dedicated to spin flippers on the source side of the UCN polarizer which would improve the polarized UCN intensity at experiments via active depolarization. Part 2 covers the design, study and construction of an additional gradient UCN spin flipper in the outgoing polarizer gradient field. It will serve to manipulate the mean velocity of the delivered polarized UCN and may increase the polarized UCN density via adaption of the UCN energy spectrum to specific geometries. In Part 3 of this PhD thesis velocity dependent systematic effects in the nEDM measurement will be assessed; an absolute necessity for achieving the nEDM target sensitivity of 5×10-28 e•cm.The present proposal asks for funding of two PhD position for 2 years with an option for a 2 year prolongation. The students will be working within the UCN physics group at PSI and the international nEDM collaboration. PhD supervisor will be Dr. Bernhard Lauss (PSI), assisted by Dr. Philipp Schmidt-Wellenburg and Dr. Geza Zsigmond. The academic supervisor will be Prof.Dr. Klaus Kirch at ETH Zürich.
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