arXiv subjects

V. V. Gerasimov

Publications and source records attributed to V. V. Gerasimov.

6 recordsLinked to original sources

arXiv2026

Generation of high-OAM ultraviolet twisted light for RF-photoinjector applications

The generation of relativistic vortex electron beams via photoemission requires ultraviolet laser beams with well-controlled orbital angular momentum (OAM) and compatibility with radio-frequency (RF) photoinjector drive-laser systems. High-OAM vortex beams at a wavelength of 266 nm are generated using three fabricated diffractive optical elements integrated into an operational photoinjector beamline: a reflective fork grating, a high-topological-charge spiral phase plate, and binary axicons. The spiral phase plate produces a high-purity Laguerre-Gaussian mode with an OAM of l = 64 and a conversion efficiency of 80%, whereas binary axicons generate low-divergence quasi-Bessel beams forming a superposition of multiple OAM states with a finite OAM bandwidth imposed by their binary phase structure. Fork gratings provide flexible access to lower OAM values and enable robust modal diagnostics. The generated beams are characterized using cylindrical-lens mode conversion and radial intensity analysis, demonstrating practical control of both the OAM content and spectral bandwidth of ultraviolet structured light for accelerator-based applications.

quant-ph↗

arXiv2025

Photon Echo in Uniaxially Stressed Germanium with Antimony Donors

Photon echo is observed in n-type Ge uniaxially stressed along the [111] crystallographic direction, with a coherence relaxation time of 300 ps. The nonlinear polarization responsible for the effect originates from antimony donors. Uniaxial stress induces valley splitting of the donor states, substantially enhancing the coherence time and enabling the observation of photon echo.

physics.optics↗

arXiv2006

Measurement of helium-3 and deuterium stopping power ratio for negative muons

The measurement method and results measuring of the stopping power ratio of helium-3 and deuterium atoms for muons slowed down in the D/$^3$He mixture are presented. Measurements were performed at four values of pure $^3$He gas target densities, $ϕ_{He} = 0.0337, 0.0355, 0.0359, 0.0363$ (normalized to the liquid hydrogen density) and at a density 0.0585 of the D/$^3$He mixture. The experiment was carried out at PSI muon beam $μ$E4 with the momentum P$μ=34.0$ MeV/c. The measured value of the mean stopping ratio $S_{^3He/D}$ is $1.66\pm 0.04$. This value can also be interpreted as the value of mean reduced ratio of probabilities for muon capture by helium-3 and deuterium atoms.

nucl-ex↗

arXiv2005

Nuclear fusion in muonic deuterium-helium complex

Experimental study of the nuclear fusion reaction in charge-asymmetrical d-mu-3He complex is presented. The 14.6 MeV protons were detected by three pairs of Si(dE-E) telescopes placed around the cryogenic target filled with the deuterium + helium-3 gas at 34 K. The 6.85 keV gamma rays emitted during the de-excitation of d-mu-3He complex were detected by a germanium detector. The measurements were performed at two target densities, 0.0585 and 0.169 (relative to liquid hydrogen density) with an atomic concentration of 3He c=0.0469. The values of the effective rate of nuclear fusion in d-mu-3He was obtained for the first time, and the J=0 nuclear fusion rate in d-mu-3He was derived.

nucl-ex↗

arXiv2003

Experimental study of $μ$--atomic and $μ$--molecular processes in pure helium and deuterium--helium mixtures

We present experimental results of $μ$--atomic and $μ$--molecular processes induced by negative muons in pure helium and helium--deuterium mixtures. The experiment was performed at the Paul Scherrer Institute (Switzerland). We measured muonic x--ray $K$ series transitions relative intensities in $(μ^{3,4}\mathrm{He})^*$ atoms in pure helium as well as in helium--deuterium mixture. The muon stopping powers ratio between helium and deuterium atoms and the $d μ^3 \mathrm{He}$ radiative decay probability of for two different helium densities in $\mathrm{D}_2 + {}^3\mathrm{He}$ mixture were also determined. Finally, the $\mathrm{q}_{1s}^{\mathrm{He}}$ probability for a $dμ$ atom formed in an excited state to reach the ground state was measured and compared with theoretical calculations using a simple cascade model.

nucl-ex↗

arXiv2003

Muon capture by 3He nuclei followed by proton and deuteron production

The paper describes an experiment aimed at studying muon capture by ${}^{3}\mathrm{He}$ nuclei in pure ${}^{3}\mathrm{He}$ and $\mathrm{D}_2 + {}^{3}\mathrm{He}$ mixtures at various densities. Energy distributions of protons and deuterons produced via $μ^-+{}^{3}\mathrm{He}\to p+n+n + ν_{μ}$ and $μ^-+{}^{3} \mathrm{He} \to d+n + ν_μ$ are measured for the energy intervals $10 - 49$ MeV and $13 - 31$ MeV, respectively. Muon capture rates, $λ_\mathrm{cap}^p (ΔE_p)$ and $λ_\mathrm{cap}^d (ΔE_d)$ are obtained using two different analysis methods. The least--squares methods gives $λ_\mathrm{cap}^p = (36.7\pm 1.2) {s}^{- 1}$, $λ_\mathrm{cap}^d = (21.3 \pm 1.6) {s}^{- 1}$. The Bayes theorem gives $λ_\mathrm{cap}^p = (36.8 \pm 0.8) {s}^{- 1}$, $λ_\mathrm{cap}^d = (21.9 \pm 0.6) {s}^{- 1}$. The experimental differential capture rates, $dλ_\mathrm{cap}^p (E_p) / dE_p $ and $ dλ_\mathrm{cap}^d (E_d) / dE_d$, are compared with theoretical calculations performed using the plane--wave impulse approximation (PWIA) with the realistic NN interaction Bonn B potential. Extrapolation to the full energy range yields total proton and deuteron capture rates in good agreement with former results.

nucl-ex↗