TITLEAccelerator
Progress of Design
Construction Status
Linac Energy Recovery Scenario

Yoshi Yamazaki
J-PARC Accelerator GroupThe 2nd International Advisory Committee Meeting
KEK, Tsukuba, March 10th to 11th, 2003

Content
1.
2.
3.
4.
5.

ReminderProgress in Design
Present Status of Costruction
Linac Energy Recovery Scenario
SummarySite View of the Project
MaterialsandLifeScience（１３０ｍ７０ｍ１４ｍ）

NuclearandParticle
Physics（１００ｍ８０ｍ １９ｍ）

NuclearWaste
Transmutation

NeutrinoProduction

Linac(350m)

Phase I50GeVMR
Synchrotron(1600m)3GeVRCS（350m）

Phase II

Proton linac

RCS Configuratiion

Injection Scheme to 50-GeV MR

Acceleration Cycle

Construction, Commissioning Schedule
Year
Item

200120022003200420052006200720082009

LinacBldg
LinacAccel

10％~100％

Power0.1%1%
Construction

Installation BeamTest
10％~100％

Power0.1%1%

3GeVBldg

Installation

Construction

BeamTest

3GeVAccel
3GeVBT
3GeVExpBldg
3GeVExpFac

Installation

Construction

BeamTest

Installation

BeamTest

Power0.1%1%50GeVBldg
Construction

10％~100％

Installation BeamTest

50GeVAccel
50GeVExpBldg
50GeVExpFac

Construction

Installation

BeamTest

TestPeriod OpentoUsers▲
StartUsage

Accelerator Group Organization (Instrument Construction) as May, 2002

Linac RF Source (9.5)
Linac Accelerating Structure (13.5)
Superconducting Linac(4.5)
Ring RF Acceleration (5)GroupLeader

Leaders
Board(3)Magnet & Power Supply (9.5)
Total Design(7.5)

Vacuum (4)Injection/Extraction (9)(FTE)
78 FTE’s in total
Additionally 32 FTE’s are from industries and from post-docs

Control (5.5)
Beam Monitor (7)Accelerator Group Organization (Instrument Construction) as March, 2003

Linac RF Source (10+2)
Linac Accelerating Structure (13+1)
Superconducting Linac(4+3)
Ring RF Acceleration (5+1)
GroupLeader

Leaders
Board(3)Magnet & Power Supply (10+3)
Total Design(8+4)

Vacuum (5+5)
Injection/Extraction (16+6)(FTE)
93 FTE’s in total
Additionally 36 FTE’s arefrom industries and from post-docs

Control (7+2)
Beam Monitor (7+2)
Facility (4+6)

2. Progress in Design
Linac to RCS Beam Transport (L3BT). More stableagainst the space charge effect ---- Takao Katon Injection Scheme to RCS ----------- Izumi Sakain The number of Q families reduced from 11 to 7------------Kazami Yamamoton Longitudinal Bucket Manipulation----------- Masanobu YamamotonNew Injection System to RCSCollimation System for RCS
Comparioson of the two beam-loss
simulations

Impedance Measurement with wire method

3. Present Status of Costruction (Linac)
Beam commissioning of MEBT ----- Masanori Ikegami
n Ion Source, present and future ------ Akira Uenon Most of the major components for 200-MeV linac wereordered (77 %). The remaining components include
l Computer Control
l Bus Duct for DTL magnets
l Installation/Alignment/Wiring/Pipingn30mA RFQ

Inside view of the RFQ
stabilized with PISLs

The 30mA RFQ
installed in the test area

MEBT PhotographWave Forms of Chopped Beam

Chopper Cavity installed at the MEBT

Beam Test Results at the MEBTCoil of Electromagnet in Drift Tube
The coil is electroformed andWire-cutted.

DTL Tank 1 with DT’s Installed

Conditioning of SDTL1

3. Present Status of Costruction (3-GeV RCS) (1)Rapid-Cycling Magnet System (including experimental
results on the stranded cables) ------- Norio Tanin Half of t he m ajor compone nts orde red (5 3 %)includingl Magnets
l Half of the magnet resonant power supplies
l Vacuum chambers in B and Q magnetsl Half of RF systeml Half of Beam Extraction Systeml Cooling Systemn

3. Present Status of Costruction (3-GeV RCS) (2)The remaining components (47 %) include
l Half of the magnet resonant power supplies
l Vacuum system including pumps and monitors
l Half of RF system including cavities
l Beam Monitors
l Beam Injection Systemsl Half of Beam Extraction Systeml Computer Controln

Ceramics Vacuum Chamber with RF ShieldR&D Bending Magnets for the RCS (1)Temperature Measurments of the End Plates3. Present Status of Costruction (50-GeV MR) (1)MA-loaded cavity system --------------- Chihiro Ohmorin Fabrication and Field Measurement of the Magnet------ Masafumi Muton Half of the major components ordered includingl Magnets and power supplies
l Vacuum systeml Beam monitor systeml Part of RF systemn

3. Present Status of Costruction (50-GeV MR) (2)The remaining components include
l Most of RF systeml Beam Injection/Extraction Systemsl Cooling systeml Computer Controll Installation/Alignment/Wiring/PipingnRF Accelerating Cavity
500 kW peak power
50 % duty
50 hours

4. Linac Energy Recovery Scenario (1)Budget Overflow
lPresent estimate of the budget overflow is approximately 85-oku yen(6.4 % of total cost).
lThe exact value is dependent upon the result of the biddings of theremaining main components.
n Increase in the RCS circumference by 10/9
n Increase in RCS aperture by a factor of 1.5 both horizontal andverticaln Much more sophist icated i njecti on system with many bumpmagnets.
n (More precise fi eld control in both phase and amplitude isnecessary for the linac in order to overcome the space charge
problem by controlling Dp/p within 0.1 %(control system, coolingwater syst em, tig hter speci fica t io n fo r t he a ccelera t ingstructures).)Comparison of the Lattice Parameters of the 3-GeV RCS (1)----- The Circumference is increased by a factor of 10/9 ---New Lattice
Circumference
348.3 mTypical Tune
(6.68, 6.27)
Transition Gamma
9.17
Maximum RF Voltage
467 kV
Maximum RF Voltage per Cavity
42 kV
The Number of RF Cavities
11 (+1)

Previous
313.5 m(7.35, 5.8)
9.05
420 kV
42 kV
10 (+1)Comparison of the Lattice Parameters of the 3-GeV Synchrotron (2)----- The Emittance is increased by a factor of 3/2 --New Lattice
Painting Emittance at Injection(p mm.mrad)
216
Collimator Acceptance324
Physical Aperture
486

Previous
144
216
324

Bunching Factor with 2nd harmonic
Incoherent Tune Shift with

0.41
0.16

0.41
0.23

Bunching Factor without
Incoherent Tune Shift

0.27
0.24

0.27
0.35

Comparison of the Lattice Parameters of the 3-GeV Synchrotron (3)The Emittance is increased by a factor of 3/2,while the gap of the BM is as it is.
The number of families is increased.

Bending
The Number of Magnets
Gap Height
Good Field Region
Quadrupole
The Number of Magnets
The Number of Families

New LatticePrevious

24210 mm
240 mm24210 mm
190 mm60766
7

4. Linac Energy Recovery Scenario (2)What to do ?
lWe have to close the ring.
lWe can inject the beam with a lower energy. Experiments with a lower
beam power are possible.
nnn

Set the minimum injection energy to 200 MeV.
Order and complete the building, the tunnel, the infrastructure,the 200-MeV linac, the 3-GeV RCS and 50-GeV MR. Thebuilding and the tunnel can accommodate the 400-MeV linac.
Waiting for the results of the bidding of the major components,
we will try to increase the linac energy as high as possible.

4. Linac Energy Recovery Scenario (3)nnThe project director and the JAERI/KEK managements have been
making and will make every effort to obtain the budget to complete the200-400 MeV linac.
Actually, the Ministry of Education, Science, Technology, Culture, andSport (Monbu-Kagaku-Sho, Mon-Ka-Sho) tried to fund this by asupplementary budget, last year, although the result was not successful.

Problem◆ Even if the proposal is approved the earliest possible, the recovery canstart in 2004, two years later than originally planned.
◆Nearly one year beam shut-down is necessary for the installation at the
midst of the high time of the experiment with a few-100 kW beam power.

This will be never approved by the users.

4. Linac Energy Recovery Scenario (4)Recovery Scenario
The components to be installed outside the tunnel can be installed
and tested without any disturbance on the beam operation.
On the other hand, the components to be installed inside the tunnel
needs the beam shut down.
nll■

Usually, the machine operation is shut down for three months inevery summer, since the electricity cost is very high in the summer
season. These three months will be used to install the cavities.
■ If the cavities are not used for the acceleration, the recovery of thebeam intensity will not take much more time than the start-up after
the usual summer shut down.
■ For this, all the lattice quadrupole magnets without the CCL should
be set in the same way as the case with the CCL. (There will be no
problem for the beam transport through the detuned CCL, althoughsome worry exists, regarding the beam blow up by the resonancehitting.)Linac Energy Recovery Schedule Proposed
2003.2.18

LINAC 400 MeV Recovery Schedule
Shut DownOperation

The First YearThe 2-nd Year

The 3-rd YearThe 4-th Year

The 5-th Year

July,Aug.
Scheduled Operation

July-Sept.

July-Sept.

July-Sept.

July-Dec.
400MeV Commissioning

Distribution Step up

Electricity

Sep.-Dec.

WiringCooling Water

Step up Work

Test RunDevice Control Program

ControlWirig
Commissioning Program
ACS Assembly Test Area Set up
RF System Set up
ACS Cavity Production
ACS Cavity Assembly ,High Power Test
ACS+Q-Mag Assembly, Alignment
Q-Mag,Beam Monitor Production and Test
Set upKly.PS

WiringProduction

RF System

Set up ,Test
ACS System Test, Tuning (Occasional)
Beam Acceleration Test (If Possible)
TunnelWG Set up

Wiring,Piping
ACS Installation

Wiring,Piping
ACS Installation

Buncher(MEBT2) Installation

Wiring,Piping
ACS Installation

RFQ,Debuncher Replace
RF System Tuning
LINAC Commissioning
3GeVCommissioning4. Linac Energy Recovery Scenario (5)nnnll

It will take three summer shut-downs for the installation.
During the beam operation, one can finish the power test and ot her
component test without any disturbance on the beam operation.
During the fourth shut down, the beam will be accelerated up to 400 MeV,
will be injected to the RCS and so forth.
It is very hard to estimate how long it takes to recover the same beam
intensity as that of the lower injection energy. We hope we need, at most,additional two or three months to the three-month shut down.
If the funding is not too late, the 400-MeV injection can start just after themaximum beam power of around 0.6 MW with the 200-MeV injection isachieved. Then, little delay in the gradual beam power up.
This scenario was reviewed by Director’s Ad Hoc Committee,
on March 5, 2003.

We would like the ATAC and IAC to support the above specification
change and the injection-energy recovery scenario from theviewpoints of the beam power margin.

Comparison of the space-charge tune shifts
Tune shift has the meaning as a scaling tool.
Table: Comparison of the Tune Shifts for Various Beam Currents and Energies.
JHF

J-PARC

J-PARCBeam Power

0.6 MW

1 MW

0.6 MW

Beam Current
Number of Particles N

200 mA
5 x 1013

333 mA
8.3 x 1013

200 mA
5 x 1013

200 MeV

400 MeV

180 MeVb g at injection

0.572

1.475

0.501

Painting Emittance e(unnormalized, p mm mrad)
Bunching Factor Bf

214
0.27

216
0.41

216
0.41

– 0.37– 0.16– 0.27

Injection Energy
2 3Tune Shift Dn

Classical Proton Radius: rp = 1.53 x 10-18
Lasslett Tune Shift: Dn = – rp N / 2pb2 g3 (e/p) Bf
1) The collimator aperture is 1.5 times as large as the painting emittance, while the physical aperture is 1.5 times as large as thecollimator one.
2) The tune shift of the SNS is – 0.20 at the injection energy of 1 GeV.
3) The collimator can stand 3% beam loss at the injection of 400 MeV. It can stand the 10% beam loss or more at 200 MeV, 200 mA.

Beam Loss in RCS with 400-MeV and 181-MeV Injections

20 mA: 0.4 MW
30 mA: 0.6 MW
40 mA: 0.8 MW
50 mA: 1.0 MW

Two Injection Schemes from 3-GeV RCS to 50-GeV MR

Fast Extraction : 15 mA (3.52 s)18.6 mA (2.84 s)
Slow Extraction: 15 mA (3.52 s)

18 mA (3.28 s)
15 mA (3.96 s)
if 0.6-MW RCS, andif 0.6-s injection is possible with this beam current (tune shift is - 0.14).

Summary■

Progress in the accelerator design has been achieved on the beam
injection system, the BT from linac to RCS, and so forth.
■ The construction of the accelerator components is on schedule, except
for the CCL.
■ The recovery scenario of the CCL is formed with little disturbance on
the beam operation.
■ Archaeological excavation of the salt pans remains may delay the civilengineering construction for the 50-GeV MR longer than half a year,
having a big impact on the beam commissioning of the MR.

Emittance Growth in RCS (400-MeV injection, 1.5 MW)
220

240

By Takayama et al.

90%

250

280

95%

320

430

99%

30A

The tuneshift of the 400-MeVinjection, 1.5-MW extractionis the same as that ofthe 180-MeV injection, 0.5-MWextraction.

Emittance Growth in RCS (400-MeV injection, 1 MW )200
By Takayama et al.
90 %
140

The 97 % emittance should
be confined in324 p mm mrad.

24095%14040099%
150Horizontal

VerticalEmittance Growth in RCS with 181-MeV Injection
80097%

700

90% Case: Emittancemust be confinedwithin 324 p mm mrad

60095%500p mm mrad)
Emittance (400300200
100001090%

203040Linac Peak Current (mA)

5060

1 MW @ 3 GeV