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Full-Text Articles in Physics
A Low-Voltage Retarding-Field Mott Polarimeter For Photocathode Characterization, J.L. Mccarter, M.L. Stutzman, K.W. Trantham, Timothy G. Anderson, A.M. Cook, Timothy J. Gay
A Low-Voltage Retarding-Field Mott Polarimeter For Photocathode Characterization, J.L. Mccarter, M.L. Stutzman, K.W. Trantham, Timothy G. Anderson, A.M. Cook, Timothy J. Gay
Timothy J. Gay Publications
Nuclear physics experiments at Thomas Jefferson National Accelerator Facility’s CEBAF rely on high polarization electron beams. We describe a recently commissioned system for prequalifying and studying photocathodes for CEBAF with a load-locked, low-voltage polarized electron source coupled to a compact retarding-field Mott polarimeter. The polarimeter uses simplified electrode structures and operates from 5 to 30 kV. The effective Sherman function for this device has been calibrated by comparison with the CEBAF 5 MeV Mott polarimeter. For elastic scattering from a thick gold target at 20 keV, the effective Sherman function is 0.201(5). Its maximum efficiency at 20 keV, defined as …
Alignment And Orientation Of Diatomic Molecules Induced By Polarized Electron Impact, Jack W. Maseberg, Timothy J. Gay
Alignment And Orientation Of Diatomic Molecules Induced By Polarized Electron Impact, Jack W. Maseberg, Timothy J. Gay
Timothy J. Gay Publications
We report measurements of linear and circular fluorescence polarizations for molecular transitions in H2, D2, and N2 induced by spin-polarized electron impact. Circular polarizations resulting from some Fulcher-α transitions in H2 and D2 are found to be significant, while the null results from nitrogen’s second positive system are consistent with an earlier measurement by the Münster group. We compare this nitrogen data to that from our previous study of nitrogen’s first negative system. Emphasis is placed on understanding the mechanisms that cause the values of circular polarization from N2 to be relatively …
Electron-Spin-Reversal Phenomenon In Optically Pumped Rubidium, E. B. Norrgard, D. Tupa, J. M. Dreiling, Timothy J. Gay
Electron-Spin-Reversal Phenomenon In Optically Pumped Rubidium, E. B. Norrgard, D. Tupa, J. M. Dreiling, Timothy J. Gay
Timothy J. Gay Publications
We have studied the optical pumping of mixtures of Rb vapor and N2 buffer gas by laser light tuned to the D1 transition having a spectral width of ∼500 MHz. The Rb densities are of the order of 1013 cm−3, while the buffer-gas pressures range from 0.1 to 10 torr. As the frequency of the right-hand circularly polarized laser is varied across the D1 absorption profile, the electron spin polarization of the Rb is found to take on negative values for small negative values of pump detuning from the absorption profile center. This occurs for …