K. M. Terwilliger

K−p charge exchange at 5, 7 and 12 GeV/c☆

Abstract In this letter we present the results obtained from a magnet spark chamber experiment on K − −p charge exchange from 5 to 12 GeV/ c . We also compare our results with the prediction of a Regge pole model.

Observation of resonance in the KO1KO1 system

Abstract We have analyzed 2560 events in the final-state K O 1 K O 1 n produced in π − p interactions at 5, 7 and 12 GeV/ c . We observe the S ∗ (1070), f O and A 2 decaying into K O 1 K O 1 . Resonance parameters, cross sections, and branching ratios are given.

Electron Model Fixed Field Alternating Gradient Accelerator

A radial sector FFAG accelerator has been constructed and successfully operated. In this 8‐sector accelerator electrons are betatron accelerated from 25 to 400 kev using both continuous and pulsed injection. The number of radial betatron oscillations per revolution may be varied from 2.3 to 3 and the number of vertical oscillations per revolution from 1 to 3. Calculations of these oscillation frequencies using various approximations are described and discussed. These frequencies have been measured statically with the unaccelerated beam and dynamically using an rf perturbing voltage on the accelerated beam. Results of these calculations and experiments are in satisfactory agreement. Effects of misalignments have been measured and are in close agreement with calculations presented. A survey has been made over a large area of the betatron oscillation stability region. The effects of the many resonances observed are in good qualitative agreement with theory.

Energy dependence of spin-spin forces in 90°cm elastic p-p scattering

Abstract We measured d σ d t(90° cm ) for ↑+ p ↑→ p + p from 1.75 to 5.5 GeV/ c , using the Argonne zero-gradient synchrotron 70% polarized proton beam and a 70% polarized proton target. We found that the spin-spin correlation parameter. A nn , equals 60% at low energy, then drops sharply to about 10% near 3.5 GeV/ c , and remains constant up to 5.5 GeV/ c .

Simultaneous Measurement of 2 and 3 Spins in Proton Proton Elastic Scattering at 6-GeV/c

Abstract The elastic cross section for proton proton scattering at 6 GeV c was measured using a 70% polarized beam and a 75% polarized target at the Argonne ZGS. In the range P ⊥ 2 = 0.5 → 2.0( GeV c ) 2 we obtained small error measurements for the ↑↑, ↓↓ and ↑↓ initial spin states perpendicular to the scattering plane. At P⊥2 = 0.5 we also measured the recoil spin and found that the 5 different cross sections were very unequal.

Betatron Oscillations in the Synchrotron

Betatron oscillations in the University of Michigan synchrotron have been investigated by exciting these oscillations with a transverse electric field. The results indicate that the betatron oscillation is composed of a group of component frequencies which are separated by the frequency of synchrotron phase oscillation. The suggested explanation of the observed splitting is the modulation of the betatron oscillation frequency by the synchroton oscillations.

A 14×14×7‐in. Thin Plate Spark Chamber

A Lucite wall spark chamber with 0.012‐in. aluminum electrodes, active dimensions 14×14×7 in., has been constructed and tested both with cosmic rays and a particle beam. The gap efficiency is nearly 100% and the time resolution ∼1 μsec. Construction methods and chamber characteristics are presented.

Measurement of Proton Proton Elastic Scattering in Pure Initial Spin States at 11.75-GeV/c

Abstract The elastic cross section for proton proton scattering at 11.75 GeV/c was measured at the Argonne ZGS using a 50% polarized target. In the range p⊥2=0.6 → 2.2 (GeV/c)2 we obtained precise measurements of d σ d t(ij) for the ⇈ ⇊, and ⇅ initial spin states perpendicular to the scattering plane. We confirmed that the asymmetry parameter, A, decreases with energy in the diffraction peak, but is approximately energy-independent at large p⊥2. We found that the spin correlation parameter cnn acquires rather dramatic structure, and at large p⊥2 seems to grow with energy.

Use of relative ionization for particle identification in multitrack spark chamber pictures

The design and operating conditions for a spark chamber used in a e (as Fe/sup 59 /sup -/ + p experiment at the Cosmotron are described briefly. Photographs are shown illustrating the considerable differences observed in spark densities of the four tracks of a given event. The relative track densities were compared with the particie velocities calculated from the reaction kinematics. An almost complete correlation was found, the lower-velocity particles were making the denser sparks. Effects other than ionization, which are important in determining spark density and must be taken into account in particle identification, are considered. (A.G.W.)

Commissioning the Polarized Beam in the AGS

After the successful operation of a high energy polarized proton beam at the Argonne Laboratory Zero Gradient Synchrotron (ZGS) was terminated, plans were made to commission such a beam at the Brookhaven National Laboratory Alternating Gradient Synchrotron (AGS). On February 23, 1984, 2 ..mu..A of polarized H/sup -/ was accelerated through the Linac to 200 MeV with a polarization of about 65%. 1 ..mu..A was injected into the AGS and acceleration attempts began. Several relatively short runs were then made during the next three months. Dedicated commissioning began in early June, and on June 26 the AGS polarized beam reached 13.8 GeV/c to exceed the previous ZGS peak momentum of 12.75 GeV/c. Commissioning continued to the point where 10/sup 10/ polarized protons were accelerated to 16.5 GeV/c with 40% polarization. Then, two experiments had a short polarized proton run. We plan to continue commissioning efforts in the fall of this year to reach higher energy, higher intensity, and higher polarization levels. We present a brief description of the facility and of the methods used for preserving the polarization of the accelerating beam.