R x B Drift Momentum Spectrometer

TL;DR

This paper introduces a novel RxB drift momentum spectrometer that uses a curved magnetic field to analyze low-momentum charged particles with high resolution, suitable for applications like the PERC beam station.

Contribution

The paper presents a new spectrometer design leveraging the RxB drift effect in a curved magnetic field, enabling precise momentum analysis of decay particles without removing the guiding field.

Findings

Achieves a momentum resolution of 14.4 keV/c with 1 mm position measurement accuracy.

Effectively measures low-momentum particles at large incident angles.

Demonstrates compatibility with the PERC beam station setup.

Abstract

We propose a new type of momentum spectrometer, which uses the RxB drift effect to disperse the charged particles in a uniformly curved magnetic field. This kind of RxB spectrometer is designed for the momentum analyses of the decay electrons and protons in the PERC (Proton and Electron Radiation Channel) beam station, which provides a strong magnetic field to guide the charged particles in the instrument. Instead of eliminating the guiding field, the RxB spectrometer evolves the field gradually to the analysing field, and the charged particles can be adiabatically transported during the dispersion and detection. The drifts of the particles have similar properties as their dispersion in the normal magnetic spectrometer. Besides, the RxB spectrometer is especially ideal for the measurements of particles with low momenta and relative large incident angles. We present a design of the RxB spectrometer, which can be used in PERC. The resolution of the momentum spectra can reach 14.4 keV/c, if the particle position measurements have a resolution of 1 mm.