A design for an electromagnetic filter for precision energy measurements at the tritium endpoint

Betti, M. G.; Biasotti, M.; Boscá, A.; Calle, F.; Carabe-Lopez, J.; Cavoto, G.; Chang, C.; Chung, W.; Cocco, A. G.; Colijn, A. P.; Conrad, J.; D’Ambrosio, N.; De Salas, P. F.; Faverzani, M.; Ferella, A.; Ferri, E.; Garcia-Abia, P.; Gomez-Tejedor, G. Garcia; Gariazzo, S.; Gatti, F.; Gentile, C.; Giachero, A.; Gudmundsson, J. E.; Hochberg, Y.; Kahn, Y.; Lisanti, M.; Mancini-Terracciano, C.; Mangano, G.; Marcucci, L. E.; Mariani, C.; Martínez, J.; Messina, M.; Molinero-Vela, A.; Monticone, E.; Nucciotti, A.; Pandolfi, F.; Pastor, S.; Pedrós, J.; De Los Heros, C. Pérez; Pisanti, O.; Polosa, A. D.; Puiu, A.; Raitses, Y.; Rajteri, M.; Rossi, N.; Santorelli, R.; Schaeffner, K.; Strid, C. F.; Tully, C. G.; Zhao, F.; Zurek, K. M.

doi:10.1016/j.ppnp.2019.02.004

We present a detailed description of the electromagnetic filter for the PTOLEMY projectto directly detect the Cosmic Neutrino Background (CNB). Starting with an initialestimate for the orbital magnetic moment, the higher-order drift process ofE×Bisconfigured to balance the gradient-Bdrift motion of the electron in such a way asto guide the trajectory into the standing voltage potential along the mid-plane of thefilter. As a function of drift distance along the length of the filter, the filter zoomsin with exponentially increasing precision on the transverse velocity component ofthe electron kinetic energy. This yields a linear dimension for the total filter lengththat is exceptionally compact compared to previous techniques for electromagneticfiltering. The parallel velocity component of the electron kinetic energy oscillates in anelectrostaticharmonictrapastheelectrondriftsalongthelengthofthefilter.Ananalysisof the phase-space volume conservation validates the expected behavior of the filterfrom the adiabatic invariance of the orbital magnetic moment and energy conservationfollowing Liouville’s theorem for Hamiltonian systems.

A design for an electromagnetic filter for precision energy measurements at the tritium endpoint / Betti, M.G., Biasotti, M., Boscá, A., Calle, F., Carabe-Lopez, J., Cavoto, G., Chang, C., Chung, W., Cocco, A.G., Colijn, A.P., Conrad, J., D’Ambrosio, N., de Salas, P.F., Faverzani, M., Ferella, A., Ferri, E., Garcia-Abia, P., Gomez-Tejedor, G.G., Gariazzo, S., Gatti, F., et al.. - In: PROGRESS IN PARTICLE AND NUCLEAR PHYSICS. - ISSN 0146-6410. - 106:(2019), pp. 120-131. [10.1016/j.ppnp.2019.02.004]