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Full-Text Articles in Physics
The Population Densities Of Argon Metastable Levels, Nada Khogeer, Chelsy Gonzalez, Milka Nikolic
The Population Densities Of Argon Metastable Levels, Nada Khogeer, Chelsy Gonzalez, Milka Nikolic
Physics and Astronomy
In this experiment, we used the optical emission spectroscopy (OES) method to obtain the main properties of low temperature Argon plasma. The experiment was sustained in powers and pressures that ranges from 30-100 W and 15-100 mTorr. We used numerical methods for the Argon kinetic model to calculate metastable levels and resonant states for the first excited states in low temperature Argon plasma. By finding the ratio of two spectral lines and finding another ratio from a different upper energy level that goes down to the same two lower energy levels, we can construct a system of two nonlinear equations. …
Antineutrino-Induced Charge Current Quasi-Elastic Neutral Hyperon Cross-Section On Argon In Argoneut, Samuel M. Borer
Antineutrino-Induced Charge Current Quasi-Elastic Neutral Hyperon Cross-Section On Argon In Argoneut, Samuel M. Borer
Honors College
This thesis outlines the first measurement of CCQE neutral hyperon production cross section in a liquid argon time projection chamber (LArTPC) through a topological study [1] and presents the ongoing progress of the addition of a calorimetric study. The analysis uses 1.20 £ 1020 protons-on-target, in the NuMI beam operating in the low energy antineutrino mode. The results of the topological study provide a total cross section measurement at the mean production energy of 3.42 GeV for CCQE neutral hyperons. The result of the topological study is consistent with the NUANCE cross section model and sets a 90% confidence level …
Measurements Of Population Densities Of Metastable And Resonant Levels Of Argon Using Laser Induced Fluorescence, M. Nikolic, J. Newton, C. I. Sukenik, L. Vuskovic, S. Popovic
Measurements Of Population Densities Of Metastable And Resonant Levels Of Argon Using Laser Induced Fluorescence, M. Nikolic, J. Newton, C. I. Sukenik, L. Vuskovic, S. Popovic
Physics Faculty Publications
We present a new approach to measure population densities of Ar I metastable and resonant excited states in low temperature Ar plasmas at pressures higher than 1 Torr. This approach combines the time resolved laser induced fluorescence technique with the kinetic model of Ar. The kinetic model of Ar is based on calculating the population rates of metastable and resonant levels by including contributions from the processes that affect population densities of Ar I excited states. In particular, we included collisional quenching processes between atoms in the ground state and excited states, since we are investigating plasma at higher pressures. …
Experimental Investigation Of Long-Lived Rydberg States In Ultracold Argon, G. Ranjit, C. I. Sukenik
Experimental Investigation Of Long-Lived Rydberg States In Ultracold Argon, G. Ranjit, C. I. Sukenik
Physics Faculty Publications
We report on our investigation of the formation and survival of long-lived Rydberg states in argon produced by pulsed laser excitation of ultracold metastable state argon atoms in a magneto-optical trap. The states studied have a 2P1/2 core. Low angular momentum Rydberg states with this core normally autoionize rapidly. If, however, atoms are excited in the presence of electric fields, higher angular momentum states, traditionally termed ZEKE states (ZEKE is derived from zero kinetic energy) can be formed. The lifetime of these states can be orders of magnitude greater than low angular momentum states. In this paper, we report on …
Photoassociative Spectroscopy Of Ultracold Metastable Argon, M. K. Shaffer, G. Ranjit, C. I. Sukenik, M. Walhout
Photoassociative Spectroscopy Of Ultracold Metastable Argon, M. K. Shaffer, G. Ranjit, C. I. Sukenik, M. Walhout
Physics Faculty Publications
We present results of photoassociative spectroscopy performed on ultracold metastable argonatoms in a magneto-optical trap. Ion spectra are obtained with laser detuning up to a few gigahertz below the 4s[3/2]2 → 4p[5/2]3 trapping transition at 811 nm and with intensities in a range of ~(102-105)ISat. We also compute dipole-dipole potentials for both singly and doubly excited diatomic molecules and use a Leroy-Bernstein analysis to determine the approximate vibrational spacings in the (s+p) and (p+p) manifolds. Based on this theoretical framework, we explain a broad background feature in our data and suggest that …
Trap Loss In A Dual-Species Rb-Ar* Magneto-Optical Trap, H. C. Busch, M. K. Shaffer, E. M. Ahmed, C. I. Sukenik
Trap Loss In A Dual-Species Rb-Ar* Magneto-Optical Trap, H. C. Busch, M. K. Shaffer, E. M. Ahmed, C. I. Sukenik
Physics Faculty Publications
We have investigated trap loss in a dual-species magneto-optical trap (MOT) comprised of 85Rb and metastable 40Ar. We measure the trap loss rate coefficients for each species due to the presence of the other as a function of trap light intensity. We clearly identify both Penning ionization of Rb by Ar* and associative ionization to form the molecular ion RbAr+ as two of the trap loss channels. We have also measured the trap loss rate coefficient for the Ar* MOT alone and observe production of Ar+ and Ar2+ ions.
Simultaneous Trapping Of Rubidium And Metastable Argon In A Magneto-Optical Trap, C. I. Sukenik, H. C. Busch
Simultaneous Trapping Of Rubidium And Metastable Argon In A Magneto-Optical Trap, C. I. Sukenik, H. C. Busch
Physics Faculty Publications
We have simultaneously confined rubidium and metastable argon in a dual-species magneto-optical trap (MOT). Here a binary mixture of atomic species from different groups of the periodic table have been optically confined at ultracold temperatures. We describe the apparatus and characterize the individual, single species MOTs and the dual-species MOT. Both fluorescence and ion production are monitored. With both species trapped, we observe ~5106 85Rb atoms and ~2106 40Ar* atoms. Realization of the dual-species trap opens the way for detailed studies of Penning and associative ionization, photoassociative spectroscopy, and eventually for the production of bound, ultracold RbAr molecules.
A Rf Discharge Cell For Saturated Absorption Spectroscopy Of Metastable Argon, C. I. Sukenik, H. C. Busch
A Rf Discharge Cell For Saturated Absorption Spectroscopy Of Metastable Argon, C. I. Sukenik, H. C. Busch
Physics Faculty Publications
We have produced a rf discharge in 40Ar and used saturated absorption spectroscopy to offset lock a Ti:Sapphire laser to the absorption peak of the 43P243D3 cooling transition at 811 nm. We describe the procedure for fabrication of the cell and production of the discharge.
Auger Resonance Decay Process In Ar 2p Shell Excitation And Ionization, Y. Lu, Wayne C. Stolte, J.A. R. Samson
Auger Resonance Decay Process In Ar 2p Shell Excitation And Ionization, Y. Lu, Wayne C. Stolte, J.A. R. Samson
Chemistry and Biochemistry Faculty Research
The production and subsequent autoionization of the Ar+ (1D2)6d1 satellite state that is formed either by shake-up or recapture during the Auger decay of a 2p vacancy in Ar has been studied by photoelectron spectroscopy in the energy region from 243 to 256 eV. The creation of near zero energy electrons below and immediately above the Ar 2p ionization threshold is discussed. Some ambiguous points in previous studies are clarified.
Argon-Photoion–Auger-Electron Coincidence Measurements Following K-Shell Excitation By Synchrotron Radiation, Jon C. Levin, C. Biedermann, N. Keller, L. Liljeby, C.-S. O, R. T. Short, Ivan A. Sellin, Dennis W. Lindle
Argon-Photoion–Auger-Electron Coincidence Measurements Following K-Shell Excitation By Synchrotron Radiation, Jon C. Levin, C. Biedermann, N. Keller, L. Liljeby, C.-S. O, R. T. Short, Ivan A. Sellin, Dennis W. Lindle
Chemistry and Biochemistry Faculty Research
Argon photoion spectra have been obtained for the first time in coincidence with K-LL and K-LM Auger electrons, as a function of photon energy. The simplified charge distributions which result exhibit a much more pronounced photon-energy dependence than do the more complicated noncoincident spectra. In the near-K-threshold region, Rydberg shakeoff of np levels, populated by resonant excitation of K electrons, occurs with significant probability, as do double-Auger processes and recapture of the K photoelectron through postcollision interaction.