arXiv subjects

Takeyasu M. Ito

Publications and source records attributed to Takeyasu M. Ito.

7 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↗

arXiv2007

Neutron Beta Decay: Status and Future of the Asymmetry Measurement

With more intense sources of cold and ultracold neutrons becoming available and with improved experimental techniques being developed, determination of |Vud| from neutron beta decay with a similar precision to that from from superallowed beta decays is within reach. Determination of |Vud| from neutron beta decay, free from nuclear corrections, hold the most promise for a further improvement of the determination of |Vud|. The current and future neutron beta decay correlation experiments including the UCNA experiment at Los Alamos National Laboratory are reviewed

nucl-ex↗

arXiv2007

Plans for a Neutron EDM Experiment at SNS

The electric dipole moment of the neutron, leptons, and atoms provide a unique window to Physics Beyond the Standard Model. We are currently developing a new neutron EDM experiment (the nEDM Experiment). This experiment, which will be run at the 8.9 A Neutron Line at the Fundamental Neutron Physics Beamline (FNPB) at the Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory, will search for the neutron EDM with a sensitivity two orders of magnitude better than the present limit. In this paper, the motivation for the experiment, the experimental method, and the present status of the experiment are discussed.

nucl-ex↗

arXiv2006

Optimization of the Ballistic Guide Design for the SNS FNPB 8.9 A Neutron Line

The optimization of the ballistic guide design for the SNS Fundamental Neutron Physics Beamline 8.9 A line is described. With a careful tuning of the shape of the curve for the tapered section and the width of the straight section, this optimization resulted in more than 75% increase in the neutron flux exiting the 33 m long guide over a straight m=3.5 guide with the same length.

physics.ins-det↗

arXiv2005

Neutrino mass constraints on beta decay

Using the general connection between the upper limit on the neutrino mass and the upper limits on certain types of non-Standard Model interaction that can generate loop corrections to the neutrino mass, we derive constraints on some non-Standard Model $d\to ue^-\barν$ interactions. When cast into limits on $n\to pe^-\barν$ coupling constants, our results yield constraints on scalar and tensor weak interactions improved by more than an order of magnitude over the current experimental limits. When combined with the existing limits, our results yield $|C_S/C_V|\alt 5\times 10^{-3}$, $|C'_S/C_V|\alt 5\times 10^{-3}$, $|C_T/C_A| \alt 1.2\times 10^{-2}$ and $|C'_T/C_A| \alt 1.2\times 10^{-2}$.

hep-ph↗