Overcoming depolarizing resonances with dual helical partial Siberian snakes

Acceleration of polarized protons in the energy range of 5 to 25 GeV is challenging. In a medium energy accelerator, the depolarizing spin resonances are strong enough to cause significant polarization loss but full Siberian snakes cause intolerably large orbit excursions and are also not feasible since straight sections usually are too short. Recently, two helical partial Siberian snakes with double pitch design have been installed in the Brookhaven Alternating Gradient Synchrotron (AGS). With a careful setup of optics at injection and along the energy ramp, this combination can eliminate the intrinsic and imperfection depolarizing resonances otherwise encountered during acceleration to maintain a high intensity polarized beam in medium energy synchrotrons. The observation of partial snake resonances of higher than second order will also be described.

Observation of a hybrid spin resonance

A new type of spin depolarization resonance has been observed at the Brookhaven Alternating Gradient Synchrotron (AGS). This spin resonance is identified as a strong closed-orbit sideband around the dominant intrinsic spin resonance. The strength of the resonance was proportional to the 9th harmonic component of the horizontal closed orbit and proportional to the vertical betatron oscillation amplitude. This "hybrid" spin resonance cannot be overcome by the partial snake at the AGS, but it can be corrected by the harmonic orbit correctors.

Voice terminal may offer opportunities for employment to the disabled

A rapidly growing information industry based on the combined technologies of the digital computer and telecommunications offers unique opportunities for employment of the physically handicapped. In the studies reported here, the use of voice control was investigated as an alternative to mechanical control for two quadriplegic clients too severely disabled to successfully operate a typewriter keyboard. Using a recently developed voice terminal, the clients were able to type finished copy and program a remotely located computer entirely by voice control. The voice terminal is presently in production. An evaluation of the vocational potential of the voice terminal is currently being conducted by the Rehabilitation Services Administration, DHEW.