Experimental set-up and first measurements of the neutron lifetime using PENeLOPE

• Applicant: Professor Dr. Stephan Paul
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields
• Term: from 2010 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 167645463

• Final Report Year: 2023

Final Report Abstract

The lifetime of the free neutron τn is a very important input parameter for particle and astrophysics. However, it is challenging to measure due to the neutrality of the neutron and its long lifetime of around 15 minutes. Current measurements of the neutron lifetime can be categorized into two methods, disappearance or appearance measurement, depending on whether one is counting the remaining neutrons in a storage volume (disappearance method) or the decay particles emitted from a known decay volume (appearance method). At the moment, a 4σ discrepancy exists between the results of the two. PENeLOPE (Precision Experiment on the Neutron Lifetime Operating with Proton Extraction), a magneto-gravitational trap for ultracold neutrons is aiming to improve the current best neutron lifetime result of τ_n,UCNτ = 877.75 ± 0.28._stat +0.22−0.16,syst s by around a factor of three. TRIUMF is currently building a next-generation UCN source using superfluid helium and driven by a spallation target. We are proposing to perform PENeLOPE at this source once its second experimental port is open to the international user community. 0.1 s of statistical precision can be reached within a few weeks according to our simulations of the TUCAN source and the PENeLOPE experiment.

Publications

• A superconducting magnet UCN trap for precise neutron lifetime measurements. Journal of Research of the National Institute of Standards and Technology, 110(4), 357.
  Picker, R.; Altarev, I.; Brocker, J.; Gutsmiedl, E.; Hartmann, J.; Muller, A.; Paul, S.; Schott, W.; Trinks, U. & Zimmer, O.
  
• A low-temperature proton detector for a neutron lifetime experiment. 2007 IEEE Nuclear Science Symposium Conference Record (2007), 2301-2302. IEEE.
  Muller, A. R.; Altarev, I.; Angerer, H.; Hartmann, F. J.; Paul, S. & Picker, R.
  
• PAFF, a low-energy, low-flux proton accelerator for detector tests. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 582(2), 395-400.
  Müller, A.R.; Hartmann, F.J.; Paul, S.; Petzoldt, G.; Picker, R.; Simson, M.; Wirth, H.-F.; Zimmer, O. & Carli, W.
  
• The proton extraction system for PENeLOPE, a new neutron lifetime experiment In I. Tserruya, A. Galand D. Ashery, editors, Proc. of 18tf Part. and Nucl. Int. Conf. - PANIC08, page 647f. Elsevier, 2008
  R. Picker; et al.
  
• A low-temperature proton detector for a neutron lifetime experiment. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 611(2-3), 289-292.
  Müller, A.R.; Altarev, I.; Angerer, H.; Gutsmiedl, E.; Hartmann, F.J.; Materne, S.; Paul, S. & Picker, R.
  
• Investigation of titanium and polyethylene as UCN absorber materials with AbEx. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 611(2-3), 297-301.
  Picker, R.; Altarev, I.; Amos, P.; Franke, B.; Geltenbort, P.; Gutsmiedl, E.; Hartmann, F.J.; Mann, A.; Materne, S.; Müller, A.R.; Paul, S.; Stoepler, R. & Wirth, H.-F.
  
• Magnetic storage of UCN for a measurement of the neutron lifetime. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 611(2-3), 167-170.
  Ezhov, V.F.; Andreev, A.Z.; Ban, G.; Bazarov, B.A.; Geltenbort, P.; Hartman, F.J.; Glushkov, A.G.; Groshev, M.G.; Knyazkov, V.A.; Kovrizhnykh, N.A.; Naviliat-Cuncic, O.; Krygin, G.B.; Mueller, A.; Paul, S.; Picker, R.; Ryabov, V.L.; Serebrov, A. & Zimmer, O.
  
• PENeLOPE—on the way towards a new neutron lifetime experiment with magnetic storage of ultra-cold neutrons and proton extraction. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 611(2-3), 176-180.
  Materne, S.; Picker, R.; Altarev, I.; Angerer, H.; Franke, B.; Gutsmiedl, E.; Hartmann, F.J.; Müller, A.R.; Paul, S. & Stoepler, R.
  
• The puzzle of neutron lifetime. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 611(2-3), 157-166.
  Paul, Stephan
  
• Transmission measurements of guides for ultra-cold neutrons using UCN capture activation analysis of vanadium. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 612(2), 349-353.
  Frei, A.; Schreckenbach, K.; Franke, B.; Hartmann, F.J.; Huber, T.; Picker, R.; Paul, S. & Geltenbort, P.
  
• The neutron and the Universe - History of a relationship. Proceedings of 50th International Winter Meeting on Nuclear Physics — PoS(Bormio2012) (c(2012, 10, 12)), 025. Sissa Medialab.
  Paul, Stephan
  
• Polarizing Ultra-Cold Neutrons for the Superconducting Trap PENeLOPE. Next Generation Experiments to Measure the Neutron Lifetime (c(2014, 3, 27)), 155-165. WORLD SCIENTIFIC.
  PICKER, R.; SCHREYER, W.; HAAS, F.; HARTMANN, F.J.; LOSEKAMM, M.; PAUL, S.; STOEPLER, R. & TIETZE, C.
  
• Intelligent FPGA data acquisition framework. 2016 IEEE-NPSS Real Time Conference (RT) (c(2016, 6)), 1-2. IEEE.
  Bai, Yunpeng; Gaisbauer, Dominic; Huber, Stefan; Konorov, Igor; Levit, Dmytro; Steffen, Dominik & Paul, Stephan
  
• Self-triggering readout system for the neutron lifetime experiment PENeLOPE. Journal of Instrumentation, 11(02), C02068-C02068.
  Gaisbauer, D.; Bai, Y.; Konorov, I.; Paul, S. & Steffen, D.
  
• Self-triggering readout system for the neutron lifetime experiment PENeLOPE. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 824(c(2016, 7)), 290-291.
  Gaisbauer, D.; Konorov, I.; Steffen, D. & Paul, S.
  
• Unified communication framework. 2016 IEEE-NPSS Real Time Conference (RT) (c(2016, 6)), 1-2. IEEE.
  Gaisbauer, Dominic; Bai, Yunpeng; Huber, Stefan; Konorov, Igor; Levit, Dymitro; Paul, Stephan & Steffen, Dominik
  
• Consistent description of UCN transport properties, arXiv:1701.07431v1 [physics.insdet], 2017
  S. Wlokka; P. Fierlinger; A. Frei; P. Geltenbort; S. Paul; T. Pöschl; F. Schmid; W. Schreyer & D. Steffen
  
• Intelligent FPGA Data Acquisition Framework. IEEE Transactions on Nuclear Science, 64(6), 1219-1224.
  Bai, Yunpeng; Gaisbauer, Dominic; Huber, Stefan; Konorov, Igor; Levit, Dmytro; Steffen, Dominik & Paul, Stephan
  
• PENTrack—a simulation tool for ultracold neutrons, protons, and electrons in complex electromagnetic fields and geometries. Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 858(c(2017, 6)), 123-129.
  Schreyer, W.; Kikawa, T.; Losekamm, M.J.; Paul, S. & Picker, R.