1
|
Serebrov A, Varlamov V, Kharitonov A, Fomin A, Pokotilovski Y, Geltenbort P, Butterworth J, Krasnoschekova I, Lasakov M, Tal'daev R, Vassiljev A, Zherebtsov O. Measurement of the Neutron Lifetime Using a Gravitational Trap and a Low-Temperature Fomblin Coating. J Res Natl Inst Stand Technol 2005; 110:333-8. [PMID: 27308146 PMCID: PMC4852839 DOI: 10.6028/jres.110.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/11/2004] [Indexed: 05/28/2023]
Abstract
We present a new value for the neutron lifetime of 878.5 ± 0.7stat. ± 0.3syst. This result differs from the world average value by 6.5 standard deviations and by 5.6 standard deviations from the previous most precise result. However, this new value for the neutron lifetime together with a β-asymmetry in neutron decay, A 0, of -0.1189(7) is in a good agreement with the Standard Model.
Collapse
Affiliation(s)
- A Serebrov
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina, Leningrad District, Russia
| | - V Varlamov
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina, Leningrad District, Russia
| | - A Kharitonov
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina, Leningrad District, Russia
| | - A Fomin
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina, Leningrad District, Russia
| | - Yu Pokotilovski
- Joint Institute for Nuclear Research, Dubna, Moscow Region, 141980, Russia
| | - P Geltenbort
- Institut Max von Laue-Paul Langevin, B.P. 156, 38042 Grenoble Cedex 9, France
| | - J Butterworth
- Institut Max von Laue-Paul Langevin, B.P. 156, 38042 Grenoble Cedex 9, France
| | - I Krasnoschekova
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina, Leningrad District, Russia
| | - M Lasakov
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina, Leningrad District, Russia
| | - R Tal'daev
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina, Leningrad District, Russia
| | - A Vassiljev
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina, Leningrad District, Russia
| | - O Zherebtsov
- Petersburg Nuclear Physics Institute, Russian Academy of Sciences, 188300 Gatchina, Leningrad District, Russia
| |
Collapse
|
2
|
Dzhosyuk SN, Copete A, Doyle JM, Yang L, Coakley KJ, Golub R, Korobkina E, Kreft T, Lamoreaux SK, Thompson AK, Yang GL, Huffman PR. Determination of the Neutron Lifetime Using Magnetically Trapped Neutrons. J Res Natl Inst Stand Technol 2005; 110:339-43. [PMID: 27308147 PMCID: PMC4852826 DOI: 10.6028/jres.110.050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/11/2004] [Indexed: 05/26/2023]
Abstract
We report progress on an experiment to measure the neutron lifetime using magnetically trapped neutrons. Neutrons are loaded into a 1.1 T deep superconducting Ioffe-type trap by scattering 0.89 nm neutrons in isotopically pure superfluid (4)He. Neutron decays are detected in real time using the scintillation light produced in the helium by the beta-decay electrons. The measured trap lifetime at a helium temperature of 300 mK and with no ameliorative magnetic ramping is substantially shorter than the free neutron lifetime. This is attributed to the presence of neutrons with energies higher than the magnetic potential of the trap. Magnetic field ramping is implemented to eliminate these neutrons, resulting in an [Formula: see text] trap lifetime, consistent with the currently accepted value of the free neutron lifetime.
Collapse
Affiliation(s)
| | - A Copete
- Harvard University, Cambridge, MA 02138, USA
| | - J M Doyle
- Harvard University, Cambridge, MA 02138, USA
| | - L Yang
- Harvard University, Cambridge, MA 02138, USA
| | - K J Coakley
- National Institute of Standards and Technology, Boulder, CO 80303, USA
| | - R Golub
- North Carolina State University, Raleigh, NC 27695, USA
| | | | - T Kreft
- Tulane University, New Orleans, LA 70118, USA
| | - S K Lamoreaux
- Los Alamos National Laborataory, Los Alamos, NM 87545, USA
| | - A K Thompson
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - G L Yang
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - P R Huffman
- North Carolina State University, Raleigh, NC 27695, USA
| |
Collapse
|
3
|
Yerozolimsky B, Steyerl A, Kwon O, Luschikov V, Strelkov A, Geltenbort P, Achiwa N, Pichlmaier A, Fierlinger P. Neutron Lifetime Experiment Based on an Accordion-Like UCN Storage Volume Coated With "Low Temperature Fomblin". J Res Natl Inst Stand Technol 2005; 110:351-356. [PMID: 27308149 PMCID: PMC4852844 DOI: 10.6028/jres.110.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/11/2004] [Indexed: 06/06/2023]
Abstract
A new type of per-fluorinated polymer, "Low Temperature Fomblin," has been tested as a wall coating in an ultracold neutron (UCN) storage experiment using a gravitational storage system. The data show a UCN reflection loss coefficient η as low as ≈ 5 × 10(-6) in the temperature range 105 K to 150 K. We plan to use this oil in a new type of neutron lifetime measurement, where a bellows system ("accordion") enables to vary the trap size in a wide range while the total surface area and distribution of surface area over height remain constant. These unique characteristics, in combination with application of the scaling technique developed by W. Mampe et al. in 1989, ensure exact linearity for the extrapolation from inverse storage lifetimes to the inverse neutron lifetime. Linearity holds for any energy dependence of loss coefficient µ(E). Using the UCN source at the Institut Laue Langevin we expect to achieve a lifetime precision below ±1 s.
Collapse
Affiliation(s)
| | - A Steyerl
- University of Rhode Island, Kingston, RI, USA
| | - O Kwon
- University of Rhode Island, Kingston, RI, USA
| | - V Luschikov
- Joint Institute for Nuclear Research, Dubna, Russia
| | - A Strelkov
- Joint Institute for Nuclear Research, Dubna, Russia
| | | | | | | | | |
Collapse
|
4
|
Wietfeldt FE, Dewey MS, Gilliam DM, Nico JS, Fei X, Snow WM, Greene GL, Pauwels J, Eykens R, Lamberty A, Van Gestel J. Measurement of the Neutron Lifetime by Counting Trapped Protons. J Res Natl Inst Stand Technol 2005; 110:327-331. [PMID: 27308145 PMCID: PMC4852842 DOI: 10.6028/jres.110.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/11/2004] [Indexed: 06/06/2023]
Abstract
We measured the neutron decay lifetime by counting in-beam neutron decay recoil protons trapped in a quasi-Penning trap. The absolute neutron beam fluence was measured by capture in a thin (6)LiF foil detector with known efficiency. The combination of these measurements gives the neutron lifetime: τ n = (886.8 ± 1.2 ± 3.2) s, where the first (second) uncertainty is statistical (systematic) in nature. This is the most precise neutron lifetime determination to date using an in-beam method.
Collapse
Affiliation(s)
| | - M S Dewey
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - D M Gilliam
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - J S Nico
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - X Fei
- Indiana University, Bloomington, IN 47408
| | - W M Snow
- Indiana University, Bloomington, IN 47408
| | - G L Greene
- University of Tennessee/Oak Ridge National Laboratory, Knoxville, TN 37996
| | - J Pauwels
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 2440 Geel, Belgium
| | - R Eykens
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 2440 Geel, Belgium
| | - A Lamberty
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 2440 Geel, Belgium
| | - J Van Gestel
- European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, 2440 Geel, Belgium
| |
Collapse
|
5
|
Picker R, Altarev I, Bröcker J, Gutsmiedl E, Hartmann J, Müller A, Paul S, Schott W, Trinks U, Zimmer O. A Superconducting Magnet UCN Trap for Precise Neutron Lifetime Measurements. J Res Natl Inst Stand Technol 2005; 110:357-360. [PMID: 27308150 PMCID: PMC4852837 DOI: 10.6028/jres.110.053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/11/2004] [Indexed: 06/06/2023]
Abstract
Finite-element methods along with Monte Carlo simulations were used to design a magnetic storage device for ultracold neutrons (UCN) to measure their lifetime. A setup was determined which should make it possible to confine UCN with negligible losses and detect the protons emerging from β-decay with high efficiency: stacked superconducting solenoids create the magnetic storage field, an electrostatic extraction field inside the storage volume assures high proton collection efficiency. Alongside with the optimization of the magnetic and electrostatic design, the properties of the trap were investigated through extensive Monte Carlo simulation.
Collapse
Affiliation(s)
- R Picker
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| | - I Altarev
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| | - J Bröcker
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| | - E Gutsmiedl
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| | - J Hartmann
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| | - A Müller
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| | - S Paul
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| | - W Schott
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| | - U Trinks
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| | - O Zimmer
- Technical University Munich, Physics Department E 18, D-85748 Garching, Germany
| |
Collapse
|
6
|
Bowman JD, Penttila SI. On the Measurement of the Neutron Lifetime Using Ultracold Neutrons in a Vacuum Quadrupole Trap. J Res Natl Inst Stand Technol 2005; 110:361-366. [PMID: 27308151 PMCID: PMC4852816 DOI: 10.6028/jres.110.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 08/11/2004] [Indexed: 06/06/2023]
Abstract
We present a conceptual design for an experiment to measure the neutron lifetime (~886 s) with an accuracy of 10(-4). The lifetime will be measured by observing the decay rate of a sample of ultracold neutrons (UCN) confined in vacuum in a magnetic trap. The UCN collaboration at Los Alamos National Laboratory has developed a prototype UCN source that is expected to produce a bottled UCN density of more than 100/cm(3) [1]. The availability of such an intense source makes it possible to approach the measurement of the neutron lifetime in a new way. We argue below that it is possible to measure the neutron lifetime to 10(-4) in a vacuum magnetic trap. The measurement involves no new technology beyond the expected UCN density. If even higher densities are available, the experiment can be made better and/or less expensive. We present the design and methodology for the measurement. The slow loss of neutrons that have stable orbits, but are not energetically trapped would produce a systematic uncertainty in the measurement. We discuss a new approach, chaotic cleaning, to the elimination of quasi-neutrons from the trap by breaking the rotational symmetry of the quadrupole trap. The neutron orbits take on a chaotic character and mode mixing causes the neutrons on the quasi-bound orbits to leave the trap.
Collapse
Affiliation(s)
- J David Bowman
- Los Alamos National Laboratory, Los Alamos, NM 87544, USA
| | - S I Penttila
- Los Alamos National Laboratory, Los Alamos, NM 87544, USA
| |
Collapse
|
7
|
Arif M, Dewey MS, Greene GL, Snow WM. Facilities for Fundamental Neutron Physics Research at the NIST Cold Neutron Research Facility. J Res Natl Inst Stand Technol 1993; 98:135-144. [PMID: 28053463 PMCID: PMC4927244 DOI: 10.6028/jres.098.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/08/1992] [Indexed: 06/02/2023]
Abstract
The features of two fundamental neutron physics research stations at the NIST cold neutron research facility are described in some detail. A list of proposed initial experimental programs for these two stations is also given.
Collapse
Affiliation(s)
- M Arif
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - M S Dewey
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - G L Greene
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| | - W M Snow
- National Institute of Standards and Technology, Gaithersburg, MD 20899
| |
Collapse
|