arXiv subjects

M. Mostamand

Publications and source records attributed to M. Mostamand.

5 recordsLinked to original sources

arXiv2025

Exploring the Onset of Collectivity Approaching N=40 through Manganese Masses

Isotopes in the region of the nuclear chart below $^{68}\mathrm{Ni}$ have been the subject of intense experimental and theoretical effort due to the potential onset of a new ``island of inversion'' when crossing the harmonic oscillator subshell closure at $N = 40$. We have measured the masses of $^{64-68}\textrm{Mn}$ using TITAN's multiple-reflection time-of-flight mass spectrometer, resulting in the first precision mass measurements of $^{67}\mathrm{Mn}$ and $^{68}\mathrm{Mn}$. These results are compared to \textit{ab initio} calculations and modern shell model calculations and show an increase in collectivity approaching $N=40$.

nucl-ex↗

arXiv2020

Resonance Laser Ionization Spectroscopy of Selenium

Photoionization spectra of Se have been studied by step-wise resonance laser ionization. The Rydberg series 4s$^2$4p$^3$($^4$S)np $^3$P$_{0,1,2}$ and 4s$^2$4p$^3$($^4$S)np $^5$P$_{1,2,3}$ were measured via different excitation schemes. Using the Rydberg series 4s$^2$4p$^3$($^4$S)np $^3$P$_2$ with n=15-33, the ionization potential of Se was determined with improved precision to 76658.15(2)$_{stat}$(4)$_{sys}$ cm$^{-1}$, which resolved the discrepancy in previous literatures. Autoionizing (AI) spectra between the IP and two neighboring converging limits of the Se ionic states 4s$^2$4p$^3$($^2$D$_{3/2}$) and 4s$^2$4p$^3$($^2$D$_{5/2}$) were obtained. In total eight AI Rydberg series have been observed, measured and assigned.

physics.atom-ph↗

arXiv2020

Production of clean rare isotope beams at TRIUMF Ion guide laser ion source

Hot cavity resonant ionization laser ion sources (RILIS) provide a multitude of radioactive ion beams with high ionization efficiency and element selective ionization. However, in hot cavity RILIS there still remains isobaric contaminations in the extracted beam from surface ionized species. An ion guide-laser ion source (IG-LIS) has been implemented that decouples the hot isotope production region from the laser ionization volume. A number of IG-LIS runs have been conducted to provide isobar free radioactive ion beams for experiments. Isobar suppression of up to 106 has been achieved, however, IG-LIS still suffers from an intensity loss of 50-100X as compared to hot cavity RILIS. Operating parameters for IG-LIS are being optimized and design improvements are being implemented into the prototype for robust and efficient on-line operation. Recent SIMION ion optics simulation results and the ongoing development status of the IG-LIS are presented.

physics.ins-det↗

arXiv2017

Resonant Ionization Laser Ion Source (RILIS) Development on Lu and Pr

Resonance ionization laser ion sources are efficient and element selective ion sources, which are particularly well suited for radioactive ion beam facilities. Using TRIUMF's off-line laser ion source test stand with a system of tunable titanium sapphire (Ti:Sa) lasers, laser resonance ionization schemes for lutetium and praseodymium have been investigated with a particular interest to autoionizing states. New ionization schemes via Rydberg states and autoionizing states were found. Their investigation and comparison of ion yields at the off-line test stand will be discussed, and the data of on-line Lu delivery will be presented.

physics.atom-ph↗

arXiv2017

Study of even-parity Rydberg and autoionizing states of lutetium by laser resonance ionization spectroscopy

Multi-step laser resonance ionization spectroscopy of lutetium (Lu) has been performed at TRIUMF's off-line laser ion source test stand. The even-parity Rydberg series $6s^2nd$ $^2D_{3/2}$, $6s^2nd$ $^2D_{5/2}$ and $6s^2ns$ $^2S_{1/2}$ were observed converging to the 6s$^2$ ionization potential. The experimental results has been compared to previous work. 51 levels of Rydberg series $6s^2nd$ $^2D_{5/2}$ and 52 levels of Rydberg series $6s^2ns$ $^2S_{1/2}$ were reported new. Additionally six even-parity autoionization (AI) series converging to Lu ionic states $5d6s$ $^3D_1$ and $5d6s$ $^3D_2$ were observed. The level energies of these AI states were measured. The configurations of the AI states were assigned by relativistic multichannel theory (RMCT) within the framework of multichannel quantum defect theory (MQDT).

physics.atom-ph↗