Effective DC acceleration of charged particles in a circular ring and its potential application.

A novel scheme is proposed for realizing effective DC acceleration of charged particles in a circular ring. The key is to use an induction acceleration cell with multi-insulating gaps that allow forced short circuit using solid-state switching devices such as SiC-MOSFET or unforced short circuit using diodes. A baseline design of the induction acceleration cell is shown.

Fourth generation switching power supply for circular induction accelerators.

A switching power supply (SPS) was applied as the high-frequency bipolar high-voltage pulse source required to accelerate charged particles in the induction synchrotron, which was a novel synchrotron proposed at the High Energy Accelerator Research Organization (KEK) in 2006, and it was also used in other circular induction accelerators proposed thereafter, including the induction sector cyclotron and the induction microtron. As the heart of the circular induction accelerator, the SPS has recently been developed up to a fourth generation system that uses newly developed 3.3 kV high-speed SiC metal-oxide-semiconductor field-effect transistors(MOSFETs).

Development of the C(6+) laser ablation ion source for the KEK digital accelerator.

A laser ion source that provides a fully ionized carbon ion beam is under joint development at the High Energy Accelerator Research Organization and Brookhaven National Laboratory. Long-pulse (6 ns) and short-pulse (500 ps) laser systems were tested by using them to irradiate a graphite target. Notable differences between the systems were observed in these experiments.

Thermodynamic quantities of surface formation of aqueous electrolyte solutions X. Aqueous solution of 2:1 valence-type salts.

The behaviors of a series of calcium halides and of alkali earth metal chlorides in the air/water surface region were studied in comparison with those of alkali metal halides by measuring the surface tension increments of solutions. The effect of salts with divalent cations on the surface tension increments is more pronounced than that of uni-univalent salts, but there are some similarities between these two types. It seems that the anions cause a marked effect on surface tension which is proportional to the magnitude of hydration in the bulk water.

Thermodynamic quantities of surface formation of aqueous electrolyte solutions: IX. Aqueous solutions of ammonium salts.

The properties of aqueous ammonium salt solutions at the air/water surface are presented. By comparison of the properties of ammonium halides solutions with those of sodium halide, we note a close similarity, which indicates that the increments in surface tension may be explained in relation to the hydration enthalpy of anions. We find that the behaviors of the salts with nitrate anions which are polyatomic are also explained by hydration enthalpy in the same way.

Experimental demonstration of the induction synchrotron.

We report an experimental demonstration of the induction synchrotron, the concept of which has been proposed as a future accelerator for the second generation of neutrino factory or hadron collider. The induction synchrotron supports a superbunch and a superbunch permits more charge to be accelerated while observing the constraints of the transverse space-charge limit. By using a newly developed induction acceleration system instead of radio-wave acceleration devices, a single proton bunch injected from the 500 MeV booster ring and captured by the barrier bucket created by the induction step voltages was accelerated to 6 GeV in the KEK proton synchrotron.

Quasiadiabatic, nonfocusing transition-energy crossing.

A quasiadiabatic nonfocusing transition-energy crossing is proposed for suppressing any nonadiabatic and undesired features in a longitudinally separated function-type accelerator, in which particles are confined by an radio-frequency voltage with an adiabatic reduction of the amplitude and accelerated by a step voltage. This new method has been examined, both theoretically and experimentally.

Observation of the acceleration of a single bunch by using the induction device in the KEK proton synchrotron.

A single rf bunch in the KEK proton synchrotron was accelerated with an induction acceleration method from the injection energy of 500 MeV to 5 GeV.

Halo formation at early stage of injection in high-intensity hadron rings.

Halo formation under a nonequilibrium state for a two-dimensional Gaussian beam in a FODO lattice, which is an array of magnets where F is focusing, D is defocusing, and O is the drift space between magnets, was examined in terms of a transition of time-varying nonlinear resonances. Nonlinear resonant-interactions between individual particles and intrinsic beam-core oscillations result in a beam halo. The location of the halo is analytically tractable using canonical equations derived from an isolated resonance Hamiltonian.

Superbunch hadron colliders.

A novel concept of a high luminosity hadron collider is proposed. This would be a typical application of an induction synchrotron being newly developed. Extremely long bunches, referred to as superbunches, are generated by a multibunch stacking method employing barrier buckets at the injection into the collider and are accelerated with a step voltage induced in the induction gaps.