Showing 1–7 of 7 results for author: Rienäcker, I

Ultracold neutron energy spectrum and storage properties from magnetically induced spin depolarization

Authors: N. J. Ayres, G. Ban, G. Bison, K. Bodek, V. Bondar, T. Bouillaud, D. Bowles, G. L. Caratsch, E. Chanel, W. Chen, P. -J. Chiu, C. B. Crawford, V. Czamler, M. Daum, C. B. Doorenbos, M. Ferry, M. Fertl, A. Fratangelo, D. Galbinski, W. C. Griffith, Z. D. Grujic, K. Kirch, V. Kletzl, B. Lauss, T. Lefort , et al. (31 additional authors not shown)

Abstract: We present a novel method for extracting the energy spectrum of ultracold neutrons from magnetically induced spin depolarization measurements using the n2EDM apparatus. This method is also sensitive to the storage properties of the materials used to trap ultracold neutrons, specifically, whether collisions are specular or diffuse. We highlight the sensitivity of this new technique by comparing the… ▽ More We present a novel method for extracting the energy spectrum of ultracold neutrons from magnetically induced spin depolarization measurements using the n2EDM apparatus. This method is also sensitive to the storage properties of the materials used to trap ultracold neutrons, specifically, whether collisions are specular or diffuse. We highlight the sensitivity of this new technique by comparing the two different storage chambers of the n2EDM experiment. We validate the extraction by comparing to an independent measurement for how this energy spectrum is polarized through a magnetic-filter, and finally, we calculate the neutron center-of-mass offset, an important systematic effect for measurements of the neutron electric dipole moment. △ Less

Submitted 10 November, 2025; originally announced November 2025.

Achieving ultra-low and -uniform residual magnetic fields in a very large magnetically shielded room for fundamental physics experiments

Authors: N. J. Ayres, G. Ban, G. Bison, K. Bodek, V. Bondar, T. Bouillaud, D. Bowles, E. Chanel, W. Chen, P. -J. Chiu, C. B. Crawford, O. Naviliat-Cuncic, C. B. Doorenbos, S. Emmenegger, M. Fertl, A. Fratangelo, W. C. Griffith, Z. D. Grujic, P. G. Harris, K. Kirch, V. Kletzl, J. Krempel, B. Lauss, T. Lefort, A. Lejuez , et al. (25 additional authors not shown)

Abstract: High-precision searches for an electric dipole moment of the neutron (nEDM) require stable and uniform magnetic field environments. We present the recent achievements of degaussing and equilibrating the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute. We present the final degaussing configuration that will be used for n2EDM after numerous studies. The optim… ▽ More High-precision searches for an electric dipole moment of the neutron (nEDM) require stable and uniform magnetic field environments. We present the recent achievements of degaussing and equilibrating the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute. We present the final degaussing configuration that will be used for n2EDM after numerous studies. The optimized procedure results in a residual magnetic field that has been reduced by a factor of two. The ultra-low field is achieved with the full magnetic-field-coil system, and a large vacuum vessel installed, both in the MSR. In the inner volume of ~1.4 m^3, the field is now more uniform and below 300 pT. In addition, the procedure is faster and dissipates less heat into the magnetic environment, which in turn, reduces its thermal relaxation time from 12 h down to ~1.5 h. △ Less

Submitted 28 September, 2023; originally announced September 2023.

A large 'Active Magnetic Shield' for a high-precision experiment

Authors: C. Abel, N. J. Ayres, G. Ban, G. Bison, K. Bodek, V. Bondar, T. Bouillaud, E. Chanel, J. Chen, W. Chen, P. -J. Chiu, C. B. Crawford, M. Daum, C. B. Doorenbos, S. Emmenegger, L. Ferraris-Bouchez, M. Fertl, A. Fratangelo, W. C. Griffith, Z. D. Grujic, P. Harris, K. Kirch, V. Kletzl, P. A. Koss, J. Krempel , et al. (26 additional authors not shown)

Abstract: We present a novel Active Magnetic Shield (AMS), designed and implemented for the n2EDM experiment at the Paul Scherrer Institute. The experiment will perform a high-sensitivity search for the electric dipole moment of the neutron. Magnetic-field stability and control is of key importance for n2EDM. A large, cubic, 5m side length, magnetically shielded room (MSR) provides a passive, quasi-static s… ▽ More We present a novel Active Magnetic Shield (AMS), designed and implemented for the n2EDM experiment at the Paul Scherrer Institute. The experiment will perform a high-sensitivity search for the electric dipole moment of the neutron. Magnetic-field stability and control is of key importance for n2EDM. A large, cubic, 5m side length, magnetically shielded room (MSR) provides a passive, quasi-static shielding-factor of about 10^5 for its inner sensitive volume. The AMS consists of a system of eight complex, feedback-controlled compensation coils constructed on an irregular grid spanned on a volume of less than 1000m^3 around the MSR. The AMS is designed to provide a stable and uniform magnetic-field environment around the MSR, while being reasonably compact. The system can compensate static and variable magnetic fields up to +-50muT (homogeneous components) and +-5muT (first-order gradients), suppressing them to a few muT in the sub-Hertz frequency range. The presented design concept and implementation of the AMS fulfills the requirements of the n2EDM experiment and can be useful for other applications, where magnetically silent environments are important and spatial constraints inhibit simpler geometrical solutions. △ Less

Submitted 14 July, 2023; originally announced July 2023.

The `n2EDM MSR' -- a very large magnetically shielded room with an exceptional performance for fundamental physics measurements

Authors: N. J. Ayres, G. Ban, G. Bison, K. Bodek, V. Bondar, T. Bouillaud, B. Clement, E. Chanel, P. -J. Chiu, C. B. Crawford, M. Daum, C. B. Doorenbos, S. Emmenegger, A. Fratangelo, M. Fertl, W. C. Griffith, Z. D. Grujic, P. G. Harris, K. Kirch, J. Krempel, B. Lauss, T. Lefort, O. Naviliat-Cuncic, D. Pais, F. M. Piegsa , et al. (19 additional authors not shown)

Abstract: We present the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute which features an interior cubic volume with each side of length 2.92m, thus providing an accessible space of 25m3. The MSR has 87 openings up to 220mm diameter to operate the experimental apparatus inside, and an intermediate space between the layers for sensitive signal processing electronics.… ▽ More We present the magnetically shielded room (MSR) for the n2EDM experiment at the Paul Scherrer Institute which features an interior cubic volume with each side of length 2.92m, thus providing an accessible space of 25m3. The MSR has 87 openings up to 220mm diameter to operate the experimental apparatus inside, and an intermediate space between the layers for sensitive signal processing electronics. The characterization measurements show a remanent magnetic field in the central 1m3 below 100pT, and a field below 600pT in the entire inner volume, up to 4\,cm to the walls. The quasi-static shielding factor at 0.01\,Hz measured with a sinusoidal 2muT peak-to-peak signal is about 100,000 in all three spatial directions and rises fast with frequency to reach 10^8 above 1Hz. △ Less

Submitted 21 June, 2022; originally announced June 2022.

Comments: 10 pages, 15 Figures, submitted to Review of Scientific Instruments

Improved search for neutron to mirror-neutron oscillations in the presence of mirror magnetic fields with a dedicated apparatus at the PSI UCN source

Authors: N. J. Ayres, Z. Berezhiani, R. Biondi, G. Bison, K. Bodek, V. Bondar, P. -J. Chiu, M. Daum, R. T. Dinani, C. B. Doorenbos, S. Emmenegger, K. Kirch, V. Kletzl, J. Krempel, B. Lauss, D. Pais, I. Rienaecker, D. Ries, N. Rossi, D. Rozpedzik, P. Schmidt-Wellenburg, K. S. Tanaka, J. Zejma, N. Ziehl, G. Zsigmond

Abstract: While the international nEDM collaboration at the Paul Scherrer Institut (PSI) took data in 2017 that covered a considerable fraction of the parameter space of claimed potential signals of hypothetical neutron ($n$) to mirror-neutron ($n'$) transitions, it could not test all claimed signal regions at various mirror magnetic fields. Therefore, a new study of $n-n'$ oscillations using stored ultraco… ▽ More While the international nEDM collaboration at the Paul Scherrer Institut (PSI) took data in 2017 that covered a considerable fraction of the parameter space of claimed potential signals of hypothetical neutron ($n$) to mirror-neutron ($n'$) transitions, it could not test all claimed signal regions at various mirror magnetic fields. Therefore, a new study of $n-n'$ oscillations using stored ultracold neutrons (UCNs)is underway at PSI, considerably expanding the reach in parameter space of mirror magnetic fields ($B'$) and oscillation time constants ($τ_{nn'}$). The new apparatus is designed to test for the anomalous loss of stored ultracold neutrons as a function of an applied magnetic field. The experiment is distinguished from its predecessors by its very large storage vessel (1.47\,m$^3$), enhancing its statistical sensitivity. In a test experiment in 2020 we have demonstrated the capabilities of our apparatus. However, the full analysis of our recent data is still pending. Based on already demonstrated performance, we will reach a sensitivity to oscillation times $τ_{nn'}/\sqrt{\cos(β)}$ well above hundred seconds, with $β$ being the angle between $B'$ and the applied magnetic field $B$. The scan of $B$ will allow the finding or the comprehensive exclusion of potential signals reported in the analysis of previous experiments and suggested to be consistent with neutron to mirror-neutron oscillations. △ Less

Submitted 31 October, 2021; originally announced November 2021.

Measurement of the permanent electric dipole moment of the neutron

Authors: C. Abel, S. Afach, N. J. Ayres, C. A. Baker, G. Ban, G. Bison, K. Bodek, V. Bondar, M. Burghoff, E. Chanel, Z. Chowdhuri, P. -J. Chiu, B. Clement, C. B. Crawford, M. Daum, S. Emmenegger, L. Ferraris-Bouchez, M. Fertl, P. Flaux, B. Franke, A. Fratangelo, P. Geltenbort, K. Green, W. C. Griffith, M. van der Grinten , et al. (59 additional authors not shown)

Abstract: We present the result of an experiment to measure the electric dipole moment (EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of separated oscillating magnetic fields with ultracold neutrons (UCN). Our measurement stands in the long history of EDM experiments probing physics violating time reversal invariance. The salient features of this experiment were the use of a Hg-19… ▽ More We present the result of an experiment to measure the electric dipole moment (EDM) of the neutron at the Paul Scherrer Institute using Ramsey's method of separated oscillating magnetic fields with ultracold neutrons (UCN). Our measurement stands in the long history of EDM experiments probing physics violating time reversal invariance. The salient features of this experiment were the use of a Hg-199 co-magnetometer and an array of optically pumped cesium vapor magnetometers to cancel and correct for magnetic field changes. The statistical analysis was performed on blinded datasets by two separate groups while the estimation of systematic effects profited from an unprecedented knowledge of the magnetic field. The measured value of the neutron EDM is $d_{\rm n} = (0.0\pm1.1_{\rm stat}\pm0.2_{\rm sys})\times10^{-26}e\,{\rm cm}$. △ Less

Submitted 31 January, 2020; originally announced January 2020.

Comments: 5 pages, 4 figures, submitted to PRL on 18.12.2019

Journal ref: Phys. Rev. Lett. 124, 081803 (2020)

Data blinding for the nEDM experiment at PSI

Authors: N. J. Ayres, G. Ban, G. Bison, K. Bodek, V. Bondar, E. Chanel, P. -J. Chiu, C. Crawford, M. Daum, S. Emmenegger, L. Ferraris-Bouchez, P. Flaux, P. G Harris, Z. Grujić, N. Hild, J. Hommet, B. Lauss, T. Lefort, Y. Lemiere, M. Kasprzak, Y. Kermaidic, K. Kirch, S. Komposch, A. Kozela, J. Krempel , et al. (20 additional authors not shown)

Abstract: Psychological bias towards, or away from, a prior measurement or a theory prediction is an intrinsic threat to any data analysis. While various methods can be used to avoid the bias, e.g. actively not looking at the result, only data blinding is a traceable and thus trustworthy method to circumvent the bias and to convince a public audience that there is not even an accidental psychological bias.… ▽ More Psychological bias towards, or away from, a prior measurement or a theory prediction is an intrinsic threat to any data analysis. While various methods can be used to avoid the bias, e.g. actively not looking at the result, only data blinding is a traceable and thus trustworthy method to circumvent the bias and to convince a public audience that there is not even an accidental psychological bias. Data blinding is nowadays a standard practice in particle physics, but it is particularly difficult for experiments searching for the neutron electric dipole moment, as several cross measurements, in particular of the magnetic field, create a self-consistent network into which it is hard to inject a fake signal. We present an algorithm that modifies the data without influencing the experiment. Results of an automated analysis of the data are used to change the recorded spin state of a few neutrons of each measurement cycle. The flexible algorithm is applied twice to the data, to provide different data to various analysis teams. This gives us the option to sequentially apply various blinding offsets for separate analysis steps with independent teams. The subtle modification of the data allows us to modify the algorithm and to produce a re-blinded data set without revealing the blinding secret. The method was designed for the 2015/2016 measurement campaign of the nEDM experiment at the Paul Scherrer Institute. However, it can be re-used with minor modification for the follow-up experiment n2EDM, and may be suitable for comparable efforts. △ Less

Submitted 5 October, 2020; v1 submitted 19 December, 2019; originally announced December 2019.