PRISM RF Ultra High Field Gradient RF for Bunch Rotation

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PRISM RFUltra High Field Gradient RF for Bunch
Rotation

• Y.KURIYAMA
• OSAKA UNIV.

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Contents

• Introduction of PRISM
• PRISM RF Techniques
• RF System RD
• Summary

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Introduction of PRISM (1)
Phase Rotated Intense Slow Muon Source
105MeV e-

• Search for Lepton Flavor Violation
• B(µ-N?e-N) lt 10-18
• High Intensity
• Intence 101112 µ/sec
• Beam Repetitaion 1001000Hz
• Muon Kiematic Energy 20MeV(68MeV/c)
• High Quality
• Muon Energy Spread 0.51.0MeV
• High Purity
• Pion Contamination lt 10-18

Low E µ-
Stop µ Experiment
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Introduction of PRISM (2)

• PRISM consists of
• Pion Capture System
• Pion Decay and Muon Transport System
• Phase Rotation System

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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!

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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.
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Spec. for PRISM RF

• High Field Gradient (gt200kV/m)
• Muon has shrot life time
• Low Frequency RF (45MHz)
• 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

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

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Magnetic Cores for Cavity
Ferrites
Requirements for PRISM BV/OS400Gauss
Magnetic Alloys
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MA Core for PRISM
1.7m
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Parameters of MA Cavity
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Saw Tooth RF Shape
5ns Muon width at given momentum
RF 5MHz, 250kV/m
?p/p3
Geant3 Simulation by A.Sato
Not a sinusoidal but a saw tooth shape is needed.
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PRISM RF RD

• FY2003
• Production of AMP, Power Supply etc.
• FY2004
• AMP Commissioning by a test cavity _at_ RCNP,
  Osaka-U.
• Design production of 33 cm Cavity

????
Test Cavity
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Test RF System
AMP
Cavity
Power Supply
M-Experimental Hall, RCNP,Osaka-Univ.
Core
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RF System RD

• 43 kV/gap using 700O test cavity
• Design goal (60A RF current) of AMP was achieved.
• 33 cm cavity will be gt900O
• Very compact design for AMP and APS.

86.6kV
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PRISM Cavity Design
AMP
AMP
Cavity
Cavity
APS
APS
Beam Pipe
Beam Pipe
33cm
Side View

• 1 Gap will be produced in this FY04.

By C. Ohmori, Y. Kuriyama
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Summary

• RD 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.