arXiv subjects

Thu Nhi Tran Caliste

Publications and source records attributed to Thu Nhi Tran Caliste.

3 recordsLinked to original sources

arXiv2026

The impact of experimental conditions on the observation of channeling and crystalline undulator radiation

In this study, we present a comprehensive quantitative analysis of the radiation emitted by 855 MeV electrons propagating through an oriented diamond hetero-crystal. The crystal consists of two distinct segments: (i) a straight single-crystal diamond substrate, and (ii) a diamond layer that is periodically doped with boron atoms. The doping profiles were derived from precise experimental measurements of boron concentration obtained during the layer fabrication via Microwave Plasma Chemical Vapor Deposition (MPCVD). Our study systematically investigates the channelling and the crystalline undulator radiation, accounting for the different doping profiles in the undulating region. The simulations were conducted using the advanced MBNExplorer software package, which enables detailed modeling of particle trajectories and radiation emission. We report on good agreement with experiment and discuss remaining discrepancies providing possible explanations for them. The results obtained show that the radiation intensity is significantly affected by a range of factors, including the angular divergence of the incident beam, its orientation with respect to the target, the direction in which the emitted radiation is detected, and the choice of the doping profiles. These findings are important for optimising the design of crystalline undulators as novel gamma radiation light sources.

physics.acc-ph↗

arXiv2026

Observation of narrow-band $γ$ radiation from a boron-doped diamond superlattice with an 855 MeV electron beam

We report the first observation of narrow band 1.3 MeV $γ$ radiation from a crystalline diamond micro-undulator. A diamond superlattice was grown with a periodical varying boron doping profile. Four sinusoidally deformed (110) periods resulted with a period length of 5.0 $μ$m and an amplitude of 0.098 nm. A channeling experiment was performed with the 855 MeV electron beam of the Mainz Microtron MAMI accelerator facility. A clear peak was detected with a large sodium iodide scintillation detector close to the expected photon energy of 1.28 MeV. Key characteristics of the peak, including photon energy, width and intensity, were reproduced fairly well by Monte-Carlo simulation calculations. Based on the latter, optimized boron doping profiles were designed for a hypothetical 3 GeV electron beam, enabling preparation of a highly directional $γ$-ray beam with a photon energy of 14.5 MeV. The predicted spectral bandwidth is 13\%, however, with a high energy continuum tail. The on-target photon flux at a beam current of 100 $μ$A would be about $10^{12}$/s.

physics.ins-det↗

arXiv2024

Planar channeling of 855 MeV electrons in a boron-doped (110) diamond undulator -- a case study

A 4-period diamond undulator with a thickness of 20 $μ$m was produced with the method of Chemical Vapour Deposition (CVD), applying boron doping, on a straight diamond crystal with an effective thickness of 165.5 $μ$m. A planar (110) channeling experiment was performed with the 855 MeV electron beam of the Mainz Microtron MAMI accelerator facility to observe the expected undulator peak. The search was guided by simulation calculations on a personal computer. The code is based on the continuum potential picture, and a classical electrodynamic expression which involves explicitly the acceleration of the particle. As a result, an unexpected optimal observation angle was figured out, for which the undulator peak is strongest and the channeling radiation from the backing crystal being significantly suppressed. However, an undulator peak was not observed. Implications for the prepared undulator structure are discussed. Scatter distributions were measured for a 75 $μ$m Kapton, a 25 $μ$m aluminum foils, and a 70.7 $μ$m diamond plate in random orientation. The results were compared with Molière's scatter theory for amorphous medii. Very good agreement was found for Kapton and aluminum while for diamond the experimental width is 21\% smaller. This reduction is interpreted as coherent scattering suppression in single crystals. At tilted injection of the beam with respect to the (110) plane a clear asymmetry was observed which resembles partial beam deflection. We interpret this phenomenon heuristically as re-channeling.

physics.acc-ph↗