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e-Article

A design for an electromagnetic filter for precision energy measurements at the tritium endpoint.
Document Type
Article
Source
Progress in Particle & Nuclear Physics. May2019, Vol. 106, p120-131. 12p.
Subject
*TRITIUM
*ELECTRON kinetic energy
*LIOUVILLE'S theorem
*ENERGY measurement
*HAMILTONIAN systems
*ENERGY conservation
Language
ISSN
0146-6410
Abstract
Abstract We present a detailed description of the electromagnetic filter for the PTOLEMY project to directly detect the Cosmic Neutrino Background (CNB). Starting with an initial estimate for the orbital magnetic moment, the higher-order drift process of E × B is configured to balance the gradient- B drift motion of the electron in such a way as to guide the trajectory into the standing voltage potential along the mid-plane of the filter. As a function of drift distance along the length of the filter, the filter zooms in with exponentially increasing precision on the transverse velocity component of the electron kinetic energy. This yields a linear dimension for the total filter length that is exceptionally compact compared to previous techniques for electromagnetic filtering. The parallel velocity component of the electron kinetic energy oscillates in an electrostatic harmonic trap as the electron drifts along the length of the filter. An analysis of the phase-space volume conservation validates the expected behavior of the filter from the adiabatic invariance of the orbital magnetic moment and energy conservation following Liouville's theorem for Hamiltonian systems. [ABSTRACT FROM AUTHOR]