Performance of the Particle-Identification Silicon-Telescope Array Coupled with the VAMOS++ Magnetic Spectrometer

TL;DR

The paper introduces PISTA, a silicon-telescope array coupled with VAMOS++, for high-resolution detection of fission processes in inverse kinematics, demonstrating its particle ID and excitation energy reconstruction capabilities.

Contribution

It presents a new detection system, PISTA, optimized for high-resolution studies of fission in inverse kinematics, with detailed performance metrics and potential for advanced fission research.

Findings

Achieved 800 keV excitation energy resolution (FWHM).

Mass resolution of 1.1% (FWHM) for target-like nuclei.

Enabled detailed studies of fission as a function of excitation energy.

Abstract

The Particle-Identification Silicon-Telescope Array (PISTA) is a new detection system designed for high-resolution studies of the fission process induced by multi-nucleon transfer in inverse kinematics. It is specifically optimized for experiments with the VAMOS++ magnetic spectrometer at GANIL (Grand Acc\'el\'erateur National d'Ions Lourds). The array comprises eight trapezoidal $\Delta$E-E silicon telescopes arranged in a corolla configuration. Each telescope integrates two single-sided stripped silicon detectors, enabling target-like recoil identification, energy loss measurements, and trajectory reconstruction. Positioned in close proximity to the target, PISTA's compact geometry achieves high-efficiency tracking of target-like recoils produced in multi-nucleon transfer reactions at Coulomb barrier energies. The spatial segmentation of the array allows precise determination of the mass and charge of the target-like nucleus, and excitation energy of fissioning systems. This work presents the particle identification and excitation energy reconstruction performances for the interactions of $^{238}$U beam with $^{12}$C target. An excitation energy resolution of 800 keV (FWHM) was determined together with mass resolution of 1.1% (FWHM). The combination of PISTA and VAMOS++ magnetic spectrometer enables unprecedented investigations of the fission process as a function of the excitation energy of the fissioning nucleus, particularly for exotic systems produced in transfer-induced reactions.