A5025058927- Advanced Chemical Physics Studies
- Fermentation and Sensory Analysis
- Atomic and Molecular Physics
- Photocathodes and Microchannel Plates
- Electron and X-Ray Spectroscopy Techniques
- Atomic and Subatomic Physics Research
- Radiation Therapy and Dosimetry
- Plasma Diagnostics and Applications
- Molecular spectroscopy and chirality
- Laser Design and Applications
- Quantum optics and atomic interactions
- Photoreceptor and optogenetics research
- Mass Spectrometry Techniques and Applications
- Spectroscopy and Quantum Chemical Studies
- Consumer Packaging Perceptions and Trends
- Horticultural and Viticultural Research
- Advanced Optical Imaging Technologies
- X-ray Spectroscopy and Fluorescence Analysis
- Experimental and Theoretical Physics Studies
- Microbial Metabolic Engineering and Bioproduction
- Orbital Angular Momentum in Optics
- Advancements in Photolithography Techniques
- Fashion and Cultural Textiles
- Wine Industry and Tourism
- Quality and Management Systems
University of Nebraska at Kearney
2015-2023
University of Northern Colorado
2015
Fort Hays State University
2006-2010
University of Nebraska–Lincoln
1995-2002
Australian National University
1996-1999
Arkansas Tech University
1999
University of St. Thomas - Minnesota
1996
Missouri University of Science and Technology
1996
We present measurements of absolute cross sections for low- and intermediate-energy elastic electron scattering from , which have been measured independently on different experimental apparatus in two laboratories. The results are compared with a number previous calculations. Whilst there some interesting differences between recent determinations, the largest discrepancies observed experiment contemporary theory at very low energies.
We have measured the polarization of fluorescence emitted by noble gases He, Ne, Ar, Kr, and Xe following impact excitation polarized electrons. In ${3}^{3}$P\ensuremath{\rightarrow}${2}^{3}$S transition was studied; in heavy ${\mathit{np}}^{5}$(n+1)p${\mathrm{}}^{3}$${\mathit{D}}_{3}$\ensuremath{\rightarrow}${\mathit{np}}^{5}$(n+1)s${\mathrm{}}^{3}$${\mathit{P}}_{2}$ transitions were analyzed. investigated these as candidates for efficient optical electron polarimetry found that, because...
Absolute differential cross sections for elastic scattering of electrons from sulfur hexafluoride (SF6) have been measured at 11 incident energies between 2.7 and 75 eV angles 10° 130°. The magnetic angle-changing device Read co-workers has used to extend these measurements backward (130°-180°) below 15 eV. reveal some substantial differences with several previous determinations a reasonably good level agreement recent close-coupling calculation.
Before a GaAs photocathode can be activated to achieve negative electron affinity condition, the crystal must cleaned. This is most commonly done by ohmic, radiative, or bombardment heating. We report new technique monitor temperature of heated photocathodes observation with camera. The method robust and yields same temperatures for different samples using methods in mounting configurations.
We have searched for evidence of electron circular dichroism, Lhe Preferential transmission longirudinally polarized electrons lhrough a chiral medium, using stereoisomers camphor. Such an effect was seen by Campbell and Farago in 1987 5 eV elecvons. Within OUT detection limit (- 0.02%) we not observed asymmehic at either incident energy 1 or eV. ln preption this inquiry, also measured the total sanering cross section camphor range 0.5-5 Optical activity is rotation plane polarization...
Transient negative ions (resonances) formed during the collision of an electron with atom or molecule have been extensively studied for over thirty years. The continued interest in these states, both experimentally and theoretically, stems from profound effects that they can on scattering cross sections role electron–electron correlations play their formation quasi-stability. A selective discussion examples such resonances, involving one, two three excited electrons is given a wide range...
A computer vision system is presented that can be used to acquire position data for an experiment where human observations have traditionally been used. simple algorithm based on color discrimination automatically locate object of interest. Experiments monitored in real time using inexpensive cameras. Examples are given illustrate the applicability this autonomous acquisition.
A simple experiment is presented in which the spacing and geometric pattern of pixels mobile displays measured. The technique based on optical constructive interference. While another opportunity to demonstrate wave interference from a grating-like structure, this can also be used concepts solid state physics such as direct reciprocal lattice vectors.
The formation and decay of the two lowest-lying, triply excited resonances in autoionizing region helium spectrum (57-60 eV) have been studied by measuring electron-impact excitation functions for n = 2 singly states as a function electron scattering angle. These results offer unambiguous confirmation classification these , respectively. Furthermore, observation relative strengths features into various final enables some speculation to structure three electrons.
The design and operation of a simple inline optical electron polarimeter is presented. It based on exchange excitation ground state neon atoms. polarization determined from the degree circular subsequent 2p53p 3D3→2p53s 3P2 (6402 Å) fluorescence. This device can characterize both longitudinally transversely polarized beams in nondestructive fashion, inexpensive easily constructed.
The construction of a linear speaker array, which emits coherent sound radiation from multiple sources, is described. device an improvement over the two-speaker systems for demonstrating wave interference effects. operation array demonstrated with example data.
A procedure for observing diffraction from a circular aperture using photography equipment and commonly available light sources is presented. Commonly called the Airy pattern, such pattern characterized by central bright spot, with concentric dark rings. The images obtained in this are suitable discussing demonstrating Rayleigh's criterion introductory physics classes. It shown that patterns observed change as expected wavelength aperture.
A method for the active feedback reduction of optical instrumental intensity asymmetries is presented. It based on fast chopping two spatially separated beams light with orthogonal linear polarizations that are recombined and passed through a quarter-wave plate to yield single beam rapidly flipping helicity. Active electro-optic has been successfully employed maintain this asymmetry below 10(-5).
The precision by which an electron spin polarization measurement can be made using a noble-gas polarimeter depends directly on the accuracy of light-polarization measurement. Since electron-noble gas collisions occur in vacuum chamber and optical is generally outside chamber, this work examines effect window has perceived polarization. A model light source, lens system, are used that approximate situation found typical atomic physics experiment. It was demonstrated pressure difference 1 atm...
We have improved a polarized electron source in which unpolarized electrons undergo collisions with mixture of buffer gas molecules and optically spin-polarized Rb atoms. With nitrogen gas, the reliably provides spin polarization between 15% 25% beam currents >4 μA. Vacuum pump upgrades mitigate problems caused by denatured diffusion oil, leading to longer run times. A new differential pumping scheme allows use higher pressures up 800 mTorr. optics layout, is continuously monitored...
A long-standing problem in polarized electron physics is the lack of a traceable standard for calibrating spin polarimeters. While several polarimeters are absolutely calibrated to better than 2%, typical instrument has an inherent accuracy no 10%. This variability among makes it difficult compare advances sources between laboratories. We have undertaken effort establish 100 nm thick molecular beam epitaxy grown GaAs(110) as material which may be used derivative systems possessing solid...