The SPIN@FERMI collaboration has updated its 1991-95 Reports on the acceleration of polarized protons in Fermilabs Main Injector, which was commissioned by Fermilab. This Updated Report summarizes some updated Physics Goals for a 120-150 GeV/c polari
zed proton beam. It also contains an updated discussion of the Modifications and Hardware needed for a polarized beam in the Main Injector, along with an updated Schedule and Budget.
We recently used an rf solenoid to study the widths of rf spin resonances with both unbunched and bunched beams of 2.1 GeV_c polarized protons stored in the COSY synchrotron. A map, with unbunched beam at different fixed rf-solenoid frequencies, show
ed a very shallow possible depolarization dip at the resonance. Next we made frequency sweeps of 400Hz, centered at similar frequencies, which greatly enhanced the dip. But, with a bunched proton beam, both the fixed-frequency and frequency-sweep techniques produced similar maps, and both bunched maps showed full beam depolarization over a wide region. Moreover, both were more than twice as wide as the unbunched dip. This widening of the proton resonance due to bunching is exactly opposite to the recently observed narrowing of deuteron resonances due to bunching.
There will be a review of the history of polarized proton beams, and a discussion of the unexpected and still unexplained large transverse spin effects found in several high energy proton-proton spin experiments at the ZGS, AGS, Fermilab and RHIC. Ne
xt there will be a discussion of possible future experiments on the violent collisions elastic collisions of polarized protons at the 70 GeV U-70 accelerator at IHEP-Protvino in Russia and the new high intensity 50 GeV J-PARC at Tokai in Japan.
