PS Review Jun. 07, 2004

Overview of KEK 12 GeV PS Accelerator
Kotaro SATOH
Head, PS Division

1. Facility
Accelerator Complex
Beam Utility
Personnel

2. Operation
Operation Statistics
Beam Intensity
Intensity Upgrade for K2K
Recent Major Upgrades

3. Future of KEK PS Complex
Possibility of Operation Extension
Shutdown Scenario1. Facility
Accelerator Complex (completed in 1976)
Pre-accelerator
750 keV Cockcroft-Walton, H- ion source
Injector
40 MeV, 200 MHz Drift-Tube Linac
Booster
500 MeV, Rapid Cycle Synchrotron (20 Hz)
Main Ring
12 GeV, Fast Ext. (2.2 second cycle),Slow Ext. & Internal Target (4 second cycle)

Beam Utility
500 MeV Protons from Booster
NML(Neutron Meson Laboratory)
Neutron Science
Meson Science(Proton Therapy :closed in July, 2000)

12 GeV protons
EP1 K2K Experiment (Fast Ext.)
Kaon Experiment (Slow Ext.)
EP2

Physics Experiment (Slow Ext.)IT

Test Experiment (Internal Target)

Personnel
Professor
5
Associate Profess or 4
Research Associate 10
Technical Staff
16
Most are engaged in, supporting, or advising J-PARC construction.

2. Operation
a. History of Operation Statistics
b. Beam Intensityc. MR Beam Intensity Upgrades for K2K

ExperimentTransition Crossing Improvement
Remove cavity -like chambers and reduce the longitudinal
impedance causing the microwave instability at the transition
crossing.
Bunch Shaping with Band-limited White Noise Signal
In crease the bunch length to reduce the space charge effect.
1212

 Average intensity hadincreased from 4x10 ppp to 6x10 ppp.
 d. Integrated Proton Number for K2K Experimente. Recent Major Hardware Upgrades
Booster Synchrotron Magnet Power Supply (FY2000~2001)
Booster RF Cavities and Power Amplifiers ( FY2001~2004)3. Future of PS Complex
Hardware Status
None of PS components is reused in J
extraction kicker power supplies.

-PARC, except for MR fast

1. Pre-injector and Linac
Good beam condition
Drift Tube Tanks are stable.
Spar e parts and tubes are stored for two more year operation.
For much longer operation extension,
renewal of the RF amplifier system may be needed.
2. Booster
Good beam condition
Magnet power supply was renewed in 2001.
One of the tw o RF systems was upgraded in 2003.
The other is also to be replaced in 2004.
Spare units for injection and extraction,
spare units for bellows chamber are prepared.
Hard to increase the intensity much further,restricted by residua
l activities.
Laminated core at the magnet edge may need to be fixed.

Able to run for longer years, together with J -PARC.

3. Main Ring
Good beam condition
Spare units for injection and extraction are prepared.

Hard to increase the intensity much further.
Residual activity level is too high for maintenance.
Beam loss must be less than 500W at the extraction.
Unable to align magnets to reduce the orbit distortion.
Unable to avoid the beam loss by the scattering at extraction;
Beam traverses atmosphere along septum magnets,
and window foils. Estimated to be 5%.

Components of the magnet power supply are over -aged.
They have not been overhauled or replaced for years.
No spare u nits for condensers and transformers.
Interrupt operation for several months in case of the failure.

Hard to guarantee stable operation for longer years,
unless reasonable maintenance is planned soon.

Man Power
Half or a third of PS accelerator staff will be busy for J -PARC
from a latter half of FY2005.
MR operation in a first half of FY2005 may be supported.
PS Booster operation can be supported by about 10 staff members
and 10 operators for one or two years. In caseof heavy failures,
call OB/OG for help.
For further operation extension,
DECISION should be made soon on the PS activity.

Shutdown Scenario
For at least ten years after shutdown:
All accelerator components in the tunnel are to be kept as they are.
They are periodically inspected as radioactive materials.
The tunnel is always dehumidified to avoid rusting.
The tunnel is sometimes ventilated for inspection and maintenance.

No final plan exists for cleansing the PS.
Reuse the tunnel?
R ecycle the accelerator components?