Part III Commissioning. Proof of Principle FFAG (POP) study The world first proton FFAG –Commissioned in March 2000. –From 50 keV to 500 keV in 1ms. –Proof.

Part III

Commissioning

Proof of Principle FFAG (POP) study

• The world first proton FFAG– Commissioned in March 2000.– 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 frequency radius position

Dynamic aperture surveysingle particle simulation

Experimental results

Center of gravitymulti-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 thatenergy is increased more than thatcan 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 quadru

pole.

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.