55616452
Microwave driven extraction of stabilized spin polarized atomic hydrogen
Abstract The storage of ultracold spin-polarized hydrogen atoms offers the possibility of producing a high intensity nuclear polarized atomic hydrogen jet. We stored electron spin polarized atomic hydrogen at 0.4 K in an open 5 T magnetic storage cell. We also observed directly, for the first time, the extraction of hydrogen atoms from the storage cell by flipping their spins using a microwave driven transition. The results are being used to design a high intensity jet of nuclear polarized atomic hydrogen to be used as an internal target in the 400 GeV to 3 TeV UNK accelerator.
26176644
Overcoming intrinsic and synchrotron depolarizing resonances with a Siberian snake.
We overcame the strong {ital G}{gamma}={minus}3+{nu}{sub {ital y}} intrinsic depolarizing resonance using a Siberian snake acting on a stored beam of 177-MeV polarized protons at the Indiana University Cooler Ring. We also saw the first evidence for a synchrotron depolarizing resonance in a proton ring. Two synchrotron resonances were studied by varying the rf accelerating voltage and the imperfection field at 104 MeV. The Siberian snake also overcame these synchrotron depolarizing resonances.
28227992
First test of the Siberian snake magnet arrangement to overcome depolarizing resonances in a circular accelerator.
We studied the G\ensuremath{\gamma}=2 imperfection depolarizing resonance at 108 MeV, both with and without a Siberian snake, by varying the resonance strength while storing beams of 104- and 120-MeV polarized protons at the Indiana University Cooler Ring. We used a cylindrically symmetric polarimeter to simultaneously study the effect of a depolarizing resonance on both the vertical and radial components of the polarization. AT 104 MeV we found that the Siberian snake eliminated the effect of the nearby G\ensuremath{\gamma}=2 depolarizing resonance.
122310749
Perturbations of Friedmann-Robertson-Walker cosmological models
The mathematical principles underlying the theory of gauge-invariant perturbations of homogeneous isotropic cosmological models are discussed and a collection of useful formulae is given.
120706551
Advanced General Relativity
1. Differential geometry 2. Spinors 3. Asymptopia 4. The characteristic initial value problem.