The 150MeV proton FFAG (Fixed Field Alternating Gradient) synchrotron is under construction at KEK to investigate the possibilities of various applications such as proton beam therapy after the success of the POP FFAG synchrotron. One of distinguished features of this machine compared with the PoP FFAG is to use a new type of magnet, "Return-Yoke Free" magnet. Because there is no return-yoke in the median plane in this magnet, the beam injection and extraction become easier.

Longitudinal bunch shapes in the KEK proton synchrotron were measured by a fast bunch-monitor system, which showed the rapid growth of the instability at the frequency of ϳ1 GHz and significant beam loss just after transition energy. Temporal evolution of the microwave instability is explained for the first time with a proton-klystron model. [S0031-9007(96)02288-0] PACS numbers: 29.27.Bd

Results of modeling with the 3-D STRUCT and MARS15 codes of beam loss localization and related radiation effects are presented for the slipstacking injection to the Fermilab Main Injector. Simulations of proton beam loss are done using multi-turn tracking with realistic accelerator apertures, nonlinear fields in the accelerator magnets and time function of the RF manipulations to explain the results of beam loss measurements. The collimation system consists of one primary and four secondary collimators. It intercepts a beam power of 1.6 kW at a scraping rate of 5% of 5.5E+13 ppp, with a beam loss rate in the ring outside the collimation region of 1 W/m or less. Based on thorough energy deposition and radiation modeling, a corresponding collimator design was developed that satisfies all the radiation and engineering constraints.

In order to achieve an increase in proton intensity, Fermilab Main Injector will use a stacking process called "slip stacking" [1]. The intensity will be doubled by injecting one train of bunches at a slightly lower energy, another at a slightly higher energy, then bringing them together for the final capture. Beam studies have started for this process and we have already verified that, at least for a low beam intensity, the stacking procedure works as expected [2]

It requires Booster to be able to deliver 8-GeV proton beams to Main Injector at the intensity of 4.5×10 12 per batch with a longitudinal emittance of 0.12 eV•sec and a momentum spread (∆p) of 18 MeV in order to achieve the antiproton production rate of 24×10 10 per hour. Bunch rotation via the RFSUM reduction at the end of a cycle has been implemented to reach the goal. Afterward, it is important for us to develop diagnostic tools and tuning capabilities to make bunch rotation operationally reliable.