Surface-barrier detector with smoothly tunable thickness of depleted layer for study of ionization loss and dechanneling length of negatively charged particles channeling in a crystal

TL;DR

This paper proposes a novel semiconductor surface-barrier detector with tunable depleted layer thickness to study ionization loss and dechanneling length of negatively charged particles in crystal channeling, enabling detailed analysis of particle dynamics.

Contribution

It introduces a new method using a tunable surface-barrier detector to measure ionization loss and dechanneling length of particles in crystal channeling regimes.

Findings

Potential to measure ionization loss spectra for channeled particles

Ability to determine dechanneling length of negatively charged particles

Facilitates comparison between experimental data and theoretical models

Abstract

A new method for the experimental study of ionization loss of relativistic negatively charged particles moving in a crystal in the channeling regime using a semiconductor surface-barrier detector with smoothly tunable thickness of the depleted layer is proposed. The ionization loss can only be measured in the depleted layer of the detector. The thickness of the depleted layer in a flat semiconductor detector can be smoothly regulated by the value of the bias voltage of the detector. Therefore, the energy distribution of the ionization loss of relativistic particles which cross the detector and move in the channeling regime in the detector crystal can be measured along the path of the particles at variation of the bias voltage of the detector. Ionization loss spectra should be different for channeling and nonchanneling particles, and both fractions can be determined. The application of a Si surface-barrier detector-target is considered. Measurements with such a detector would make it possible to study: the energy distribution of ionization loss of channeling negatively and positively charged particles; spatial distribution of ionization loss as a function of the path length of channeling particles; the dechanneling length of negatively charged particles; and to clear up the role of rechanneling of the particles in the crystal. Comparison of experimental data with calculations can help to develop a description of the dynamics of motion of negatively charged particles channeling in a crystal. A better understanding of the dechanneling length properties can be useful in the production of positrons and other particles such as neutrons by an electron beam in crystals, and in the development of crystalline undulators, and at a crystal-based extraction of electron beams from a synchrotron.