arXiv subjects

Steven M. Clayton

Publications and source records attributed to Steven M. Clayton.

5 recordsLinked to original sources

arXiv2026

Electrode Design for a Cavallo High Voltage Multiplier in a Cryogenic nEDM Experiment

The Cavallo multiplier [http://archive.org/details/b28771035_0003] is an electrostatic inductance machine that can generate low-noise high voltages electrically isolated from its voltage input, making it ideally suited for precision experiments. Its in-situ production makes it especially useful in cryogenic experiments, where the use of traditional feedthroughs is challenging due to thermal, electrical, magnetic, and physical size considerations. One such experiment is a cryogenic measurement of the neutron electric dipole moment (nEDM) [arXiv:1908.09937,arXiv:2512.14975], which requires several hundred kilovolts on a measurement cell electrode in 0.4 K liquid helium (LHe). A Cavallo multiplier can generate this voltage by stepping up a smaller input (e.g., 50 kV) from a feedthrough. We designed Cavallo electrodes using finite element analysis to provide high voltage gain and low probability of electrical breakdown in the experimental apparatus. The final geometry achieves a gain of 18, providing a target of 650 kV with peak electric fields of 116 kV/cm distributed over small areas to limit breakdown risk.

physics.ins-det↗

arXiv2022

Electric dipole moments and the search for new physics

Static electric dipole moments of nondegenerate systems probe mass scales for physics beyond the Standard Model well beyond those reached directly at high energy colliders. Discrimination between different physics models, however, requires complementary searches in atomic-molecular-and-optical, nuclear and particle physics. In this report, we discuss the current status and prospects in the near future for a compelling suite of such experiments, along with developments needed in the encompassing theoretical framework.

hep-ph↗

arXiv2018

Cavallo's Multiplier for in situ Generation of High Voltage

A classic electrostatic induction machine, Cavallo's multiplier, is suggested for in situ production of very high voltage in cryogenic environments. The device is suitable for generating a large electrostatic field under conditions of very small load current. Operation of the Cavallo multiplier is analyzed, with quantitative description in terms of mutual capacitances between electrodes in the system. A demonstration apparatus was constructed, and measured voltages are compared to predictions based on measured capacitances in the system. The simplicity of the Cavallo multiplier makes it amenable to electrostatic analysis using finite element software, and electrode shapes can be optimized to take advantage of a high dielectric strength medium such as liquid helium. A design study is presented for a Cavallo multiplier in a large-scale, cryogenic experiment to measure the neutron electric dipole moment.

physics.ins-det↗

arXiv2012

Development of a SQUID-based 3He Co-magnetometer Readout for a Neutron Electric Dipole Moment Experiment

A discovery of a permanent electric dipole moment (EDM) of the neutron would provide one of the most important low energy tests of the discrete symmetries beyond the Standard Model of particle physics. A new search of neutron EDM, to be conducted at the spallation neutron source (SNS) at ORNL, is designed to improve the present experimental limit of ~10^-26 e-cm by two orders of magnitude. The experiment is based on the magnetic-resonance technique in which polarized neutrons precess at the Larmor frequency when placed in a static magnetic field; a non-zero EDM would be evident as a difference in precession frequency when a strong external electric field is applied parallel vs. anti-parallel to the magnetic field. In addition to its role as neutron spin-analyzer via the spin-dependent n+3He nuclear capture reaction, polarized helium-3 (which has negligible EDM) will serve as co-magnetometer to correct for drifts in the magnetic field. In one of the two methods that will be built into the apparatus, the helium-3 precession signal is read out by SQUID-based gradiometers. We present a design study of a SQUID system suitable for the neutron EDM apparatus, and discuss using very long leads between the pickup loop and the SQUID.

physics.ins-det↗

arXiv2010

Spin relaxation and linear-in-electric-field frequency shift in an arbitrary, time-independent magnetic field

A method is presented to calculate the spin relaxation times T1, T2 due to a non-uniform magnetic field, and the linear-in-electric-field precession frequency shift δωE when an electric field is present, in the diffusion approximation for spins confined to a rectangular cell. It is found that the rectangular cell geometry admits of a general result for T1, T2, and δωE in terms of the spatial cosine-transform components of the magnetic field.

physics.atom-ph↗