Part III Commissioning
Proof of Principle FFAG (POP) study The world first proton FFAG –Commissioned in March –From 50 keV to 500 keV in 1ms. –Proof of proton FFAG –Various beam operations
Components
POP synchrotron overview
Optics with linear approximation SAD calculation
Multi-turn injection 1 turn (left) and 5 turns (right)
Beam acceleration BPM signal
Observations of machine parameters Tune survey (dynamic) aperture survey
Tune at injection with various F/D ratio
Energy dependence Synchrotron oscillation frequencyradius position
Dynamic aperture survey single particle simulation
Experimental results
Center of gravity multi-particle simulation
Amplitude dependent tune shift
More beam manipulation study Multi bunch acceleration Acceleration with 2 fixed frequency Slow extraction with massless septum Resonance crossing
Multi bunch acceleration As long as two buckets are separated in longitudinal phase space, simultaneous acceleration is possible. Repetition rate is effectively increased.
RF pattern Second RF follow the first one.
Acceleration with two RF buckets Experimental results
Acceleration with 2 fixed frequency Idea is to accelerate a beam with two (or more) fixed frequency. By simulation, if the timing of two RF is chosen correctly, a part of a beam is accelerated.
Experimental results Black: simulation with two buckets. Green: simulation with one bucket. Red: experiment with two buckets. It is proven experimentally that energy is increased more than that can be accelerated with one bucket.
Slow extraction with massless septum Septum without septum blade. Field does not drop off shapely, rather linear decay like a quadrupole.
Field distribution (calculated and measured) Measured a model magnet.
How the massless septum works. (a)Kick by massless septum. (b)Cut by electric septum. (c)Restore the beam by massless septum.
Resonance crossing Crossing speed is a parameter
Signal at 4 RF patterns 20 deg.10 deg. 4 deg. 2deg. Red arrow indicates time when a beam hits chamber. When the ramping is slow, a beam is lost before hitting chamber.