Separated flow operation of the SHARAQ spectrometer for in-flight proton decay experiments

TL;DR

The paper introduces a new 'separated flow mode' for the SHARAQ spectrometer, enabling coincident measurements of protons and heavy-ion products in in-flight decay experiments, with high energy resolution.

Contribution

It develops and demonstrates a novel operation mode for the SHARAQ spectrometer that improves in-flight proton decay measurements by separating and measuring particles at different focal planes.

Findings

Achieved high energy resolution of 100 keV for relative energy

Successfully measured decay products in coincidence with high precision

Validated the ion-optical properties of the new mode

Abstract

New operation mode, "separated flow mode", has been developed for in-flight proton decay experiments with the SHARAQ spectrometer. In the separated flow mode, the protons and the heavy-ion products are separated and measured in coincidence at two different focal planes of SHARAQ. The ion-optical properties of the new mode were studied by using a proton beam at $246~{\rm MeV}$, and the momentum vector was properly reconstructed from the parameters measured in the focal plane of SHARAQ. In the experiment with the $({}^{16}{\rm O},{}^{16}{\rm F})$ reaction at a beam energy of $247~{\rm MeV/u}$, the outgoing ${}^{15}{\rm O}+p$ produced by the decay of ${}^{16}{\rm F}$ were measured in coincidence with SHARAQ. High energy resolutions of $100~{\rm keV}$ (FWHM) and $\sim 2~{\rm MeV}$ were achieved for the relative energy of $535~{\rm keV}$, and the ${}^{16}{\rm F}$ energy of $3940~{\rm MeV}$, respectively.