R.L. York

Measurement of the p-C analyzing power between 100 and 750 MeV and the p-Be analyzing power at 780 MeV

Abstract The inclusive p-C analyzing power has been measured for laboratory scattering angles between 4° and 25°, for energies between 100 and 750 MeV. The inclusive p-Be analyzing power has been measured at 780 MeV between 4° and 28°. The experiment was performed at LAMPF using a large solid angle polarimeter. An energy dependent empirical fit to these data as well as to data from SIN and TRIUMF is presented. The data from all three facilities are in generally good agreement.

Depolarization effects in optically pumped polarized proton sources

Abstract We discuss the electron spin depolarization of a hydrogen beam formed by charge capture in a polarized alkali vapor. An expression is derived for the final ground-state polarization of the hydrogen beam as a function of external-magnetic-field strength. This expression reveals the interesting possibility of producing a polarized beam with an unpolarized target. Some additional implications of our result for a practical polarized proton source are considered.

Volume H/sup -/ ion source development at LAMPF

One method of increasing the intensity of the LAMPF proton Storage Ring is to use a brighter H/sup -/ ion source. To develop such a source, the performance of the small LBL dipole filter and the BNL toroidal filter volume H/sup -/ sources are being investigated. Results of testing a new high-duty-factor design of the BNL toroidal filter volume source are discussed. Results of experiments to reduce the electron to H/sup -/ ratio and modulate the beam intensity in the small LBL source are presented.<<ETX>>

Systematic errors from an optically pumped polarized ion source

Abstract The systematic errors that arise in polarization measurements have been examined using the LAMPF optically pumped polarized ion source (OPPIS). Knowledge of these is important in planning precise experiments such as charge symmetry breaking or parity violation measurements.

Performance of the LAMPF optically pumped polarized ion source

In 1992, the LAMPF optically pumped polarized ion source (OPPIS) was used in experiments demanding a wide range of currents and polarizations. OPPIS was operated in different configurations to meet the differing current and polarization requirements for each experiment. We describe methods used to increase beam polarization at the expense of current for experiments that were count rate limited. OPPIS can be operated at 50 μA, giving 56% polarization, 25 μA with 65% polarization, or 2 μA with 77% polarization. The source reliability in 1992 was excellent, easily exceeding 95%. Contributions to experimental systematic errors made by the source were measured in 1992. We speculate about further improvements that can be made to OPPIS.

Optical pumping of the polarized H - ion source at LAMPF

A report is presented on experiments to understand the laser optical pumping efficiency for the Optically Pumped Polarized Ion Source (OPPIS) at LAMPF. Measurements were made of ion beam polarization and current vs. laser power and potassium vapor thickness in order to understand the dependence of source performance on laser power and other parameters. Attempts to fit the data with simple scaling models to evaluate projected performance improvements are shown. The development of economical ways to make more efficient use of available laser power is described.<<ETX>>

Measurement of DNN, DSS, DLS in pp → pp at 800 MeV

The spin transfer parameters DNN, DSS, DLS have been measured for pp elastic scattering at 800 MeV between 20° and 135° cm. These data bring the number of parameters measured at this energy to a total of 10, which is in general sufficient to determine a set of I=1 amplitudes.

Measurement of the pC and p9Be analyzing power at 800 MeV

The analyzing powers for the inclusive reactions C(p,Z)X and 9Be(p,Z)X have been measured at Tp=800 MeV. These data are valuable for use in proton polarimeter calibrations. The two analyzing powers have similar shapes, within the accuracy of the measurements.The analyzing powers for the inclusive reactions C(p,Z)X and 9Be(p,Z)X have been measured at Tp=800 MeV. These data are valuable for use in proton polarimeter calibrations. The two analyzing powers have similar shapes, within the accuracy of the measurements.

Polarization diagnostics and optical pumping development for OPPIS at LAMPF

We report improvement of the polarization diagnostics and their use in the development of the Optically Pumped Polarized Ion Source (OPPIS).

Beam dynamics calculations for the LAMPF optically pumped ion source

The space charge code SCHAR has been used to interpret some of the measurements made with the LAMPF ECR (Los Alamos Meson Physics Facility electron cyclotron resonance) source. Calculations were made for rectangular hole (ribbon beam), single hole, and multihole electrodes. Measured rotation of the plane of the ribbon beam in the constant solenoid field showed that when the polarizer cell was not utilized the beam was essentially not neutralized after it emerged from the extraction electrodes. There is evidence that when the polarizer cell is turned on the beam becomes neutralized from the polarizer back toward the electrode structure. The total measured current from single and multihole electrode with the polarizer cell on is proportional to the area of the electrode apertures. Beam simulation calculations indicate that if the beam extracted from the source is uniform across the multihole structure, then in order for the perimeter holes to provide as much current per area the beam would have to be at least partially neutralized after exiting from the electrode structure. The energy of the ions leaving the (unmodeled) ECR plasma determines the current for a given electrode structure and voltage. Electrode radial fields and beam space charge forces generate most of the transverse velocities observed as the beam exits from the electrodes. Tails present in the measured harp data could be explained by an H/sub 2//sup +/ component in the beam.<<ETX>>