PRISM RF Ultra High Field Gradient RF for Bunch Rotation Y.KURIYAMA - - PowerPoint PPT Presentation

PRISM RF

Ultra High Field Gradient RF for Bunch Rotation

Y.KURIYAMA OSAKA UNIV.

Contents

• Introduction of PRISM
• PRISM RF Techniques
• RF System R&D
• Summary

Introduction of PRISM (1)

• Search

Search for Lepton Flavor Violation for Lepton Flavor Violation

B(µ-N→e-N) < 10-18

• High Intensity

High Intensity

Intence: 1011~12 µ/sec Beam Repetitaion: 100~1000Hz Muon Kiematic Energy: 20MeV(=68MeV/c)

• High

High Quality Quality

Muon Energy Spread: ±0.5~1.0MeV

• High Purity

Pion Contamination < 10-18 Low E µ- ~105MeV e- Stop µ Experiment Phase Rotated Intense Slow Muon Source

Introduction of PRISM (2)

• PRISM consists of

– Pion Capture System – Pion Decay and Muon Transport System – Phase Rotation System

To Obtain a Muon Beam with Low Momentum Spread,

• Several Ideas
• Cooling in Synchrotron
• Linac Option

etc. But Short Life Time of Muon,

• Solution:

Bunch Rotation in a FFAG!

Phase Rotation

• Accelerates Slow Muon and Decelerates Fast Muon

by a RF Field in PRISM-FFAG ring.

• Due to Muon Life Time, Bunch Rotation should be

completed in 1µs(5turns).

High Gradient RF System is required.

• Spec. for PRISM RF
• High Field Gradient (>200kV/m)

– Muon has shrot life time

• Low Frequency RF (4~5MHz)

– Muons of low energy spread longitudinally – Difficulty to get High Voltage at Low Frequency

• Saw tooth like RF shape

– Low-Q cavity to allow Higher Harmonics – Magnetic Alloy Core (Finemet) is employed

High Field Gradient

Proton Synchrotron RF System 50 100 150 200 250 2 4 6 8 10 12 Frequency (MHz) Field Gradient (kV/m) SATUNE MIMAS CERN PSB CERN PS AGS ISIS KEK BSTR KEK PS JKJ 50GeV MR JKJ 3GeV RCS 50GeV MR Upgrade KEK-HGC

!"#$%

High Gap Voltage (×3) & Short Cavity (×2) Very High Gradient for very short moment (10ms)

To Obtain High Voltage at Low Frequency.

• Magnetic Alloy

– High Field Gradient ( -200kV/m) might be possible by an optimum design.

• Ceramic Cavity

– Very high field gradient might be possible. – Need R&D

Magnetic Cores for Cavity

Magnetic Alloys Ferrites Requirements for PRISM B=V/ΩS=400Gauss

MA Core for PRISM

1.7m

Parameters of MA Cavity

air cooling (Duty 0.1%) Cooling 1.7m X 1.0m (1 m X 0.3m aperture) Size of core 6 cores/gap (3.5cm core) # of cores 0.9kΩ/gap, Impedance 33cm/gap Length 3-4 gaps, >50 kV/gap Gaps/cavity 200- kV/cavity, -200kV/m Field gradient 4CW100,000E, DC 33-37kV, 1.5 MW(peak for 10m s) Power tube

Saw Tooth RF Shape

Not a sinusoidal but a saw tooth shape is needed. RF 5MHz, 250kV/m Δp/p=±3%

±5ns Muon width at given momentum Geant3 Simulation by A.Sato

PRISM RF R&D

• FY2003:

– Production of AMP, Power Supply etc.

• FY2004:

– AMP Commissioning by a test cavity @ RCNP, Osaka-U. – Design & production

• f 33 cm Cavity

Test Cavity

• 否

呟

Test RF System

M-Experimental Hall, RCNP,Osaka-Univ.

Cavity Power Supply AMP Core

RF System R&D

• 43 kV/gap using 700Ω

test cavity

• Design goal (60A RF

current) of AMP was achieved.

• 33 cm cavity will be

>900Ω:

• Very compact design

for AMP and APS. 86.6kV

PRISM Cavity Design

APS AMP Cavity

By C. Ohmori, Y. Kuriyama

Beam Pipe Side View 33cm

• 1 Gap will be produced in this FY04.

APS

Beam Pipe

AMP Cavity

Summary

• R&D for PRISM RF has been started in RCNP,

Osaka-U.

• AMP, PS, D-AMP and MA Cores have been

produced.

• AMP has been tested using a test cavity and

achieved 43 kV at 5MHz.

• Ultra High Field Gradient Cavity will be

produced in FY2004.

• Test of Ultra High Field Gradient in FY2005.