arXiv subjects

J. Kaur

Publications and source records attributed to J. Kaur.

4 recordsLinked to original sources

arXiv2026

Demonstration of ultra-low emittance beams in a kHz laser wakefield accelerator and application to electron diffraction

We present a compact, cost-effective method for measuring the emittance of kHz-repetition-rate laser-wakefield accelerated electron beams using a permanent solenoid. The measured normalized emittance, $\epsilon_n = 124\,\mathrm{nm \cdot rad}$ ($\simeq 0.04 \pi\,\mathrm{mm \cdot mrad}$) at $2.7\,$MeV, is comparable to that of ultra-low emittance radiofrequency guns used for electron diffraction. Leveraging this low emittance, we successfully applied the electron beam to electron diffraction. We demonstrate diffraction images obtained from a single-crystal silicon nanomembrane sample, clearly resolving diffraction peaks across multiple orders.

physics.acc-ph↗

arXiv2020

High-Harmonic Generation and Correlated Electron Emission from Relativistic Plasma Mirrors at 1 kHz Repetition Rate

We report evidence for the first generation of XUV spectra from relativistic surface high-harmonic generation (SHHG) on plasma mirrors at a kilohertz repetition rate, emitted simultaneously with energetic electrons. SHHG spectra and electron angular distributions are measured as a function of the experimentally controlled plasma density gradient scale length $L_\mathrm{g}$ for three increasingly short and intense driving pulses: 24~fs and $a_0=1.1$, 8~fs and $a_0=1.6$, and finally 4~fs and $a_0\approx2.1$, where $a_0$ is the peak vector potential normalized by $m_\mathrm{e} c/e$ with the elementary charge $e$, the electron rest mass $m_\mathrm{e}$, and the vacuum light velocity $c$. For all driver pulses, we observe correlated relativistic SHHG and electron emission in the range $L_\mathrm{g}\in[\lambda/25,\lambda/5]$, with an optimum gradient scale length of $L_\mathrm{g}\approx\lambda/10$.

physics.plasm-ph↗

arXiv2018

The $γ$-ray strength function for Thallium isotopes relevant to the $^{205}$Pb - $^{205}$Tl chronometry

Photoneutron cross sections were measured for $^{203}$Tl and $^{205}$Tl at energies between the one- and two-neutron thresholds using quasi-monochromatic $γ$-ray beams produced in laser Compton-scattering at the NewSUBARU synchrotron radiation facility. Our new measurement results in cross sections significantly different from the previously reported bremsstrahlung experiment, leading to rather different GDR parameters, in particular to lower GDR peak energies and higher peak cross sections. The photoneutron data are used to constrain the $γ$-ray strength function on the basis of the Hartree-Fock-Bogolyubov plus quasi-particle random phase approximation using the Gogny D1M interaction. Supplementing the experimentally constrained $γ$-ray strength function with the zero-limit E1 and M1 contributions for the de-excitation mode, we estimate the Maxwellian-averaged cross section for the s-process branching-point nucleus $^{204}$Tl in the context of the $^{205}$Pb - $^{205}$Tl chronometry.

nucl-ex↗

arXiv2013

Anamolous reduction of magnetic coercivity of graphene oxide and reduced graphene oxide upon cooling

In this report we present the temperature evolution of magnetic coercivity of graphene oxide (GO) and reduced graphene oxide (RGO). We report an anamolous decrease in coercivity of GO and RGO with decreasing temperature. We could explain this anamolous behavior invoking the inherent presence of ripple in graphene. We observe antiferromagnetic and ferromagnetic behavior at room temperature for GO and RGO respectively, but at low temperatures both shows paramagnetic behavior.

cond-mat.mtrl-sci↗