Synchrotron Overview Tadashi Koseki J-PARC center, KEK&JAEA - - PowerPoint PPT Presentation

Synchrotron Overview

Tadashi Koseki J-PARC center, KEK&JAEA Accelerator Laboratory, KEK ICFA mini-Workshop on Beam Commissioning for High Intensity Accelerators CSNS site, June 8, 2015

Contents

• 1. High power proton synchrotrons
• 2. High luminosity colliders
• 2. Challenges for high power accelerator operation
• 2. Acknowledgements

High power proton synchrotrons

Hadron accelerators in the world

Jie Wei / Y. Yamazaki 1 MW

High power proton synchrotrons/rings operating as a front-runner

Spallation Neutron Source, ORNL 1-GeV AR, 1.4 MW Main Injector, FNAL 120-GeV Synchrotron, 700 kW J-PARC, KEK&JAEA 3-GeV RCS, 1 MW / 30-GeV MR , 750 kW ISIS, STFC 800-MeV RCS, 200 kW

SNS Accelerator Complex

Front-End:

Produce a 1-msec long, chopped, H- beam

1 GeV LINAC Accumulator Ring:

Compress 1 msec long pulse to 700 nsec

2.5 MeV

LINAC LINAC Front-End Front-End

Accumulator Ring

RTBT HEBT

Injection Extraction RF Collimators

945 ns 1 ms macropulse

Current mini-pulse Chopper system makes gaps Current

1ms

Liquid Hg Target

1000 MeV

Courtesy of M. Plum

SNS beam power vs time

1.4 MW

Target issues

1.0 MW

• Demonstrated full design beam power for >24 hours for neutron scattering experiments, at the end
• f a run cycle, in June 2014.
• At the beginning of the next run cycle, had a target failure, then other one in October 2014.
• Operated at reduced power, about 850 kW, until they could get more spare targets. Restarted high

power operations in April 2015.

• Now operating at 1.1-1.3 MW, depending on warm linac cavity conditioning after an RF window

replacement and/or condition of the ion source.

Challenge for target improvement

• Target failures

– 5 out of the last 11 targets have failed at weld joints – New designs to improve / eliminate weld joints

Leak detector fluid “bubbling” through weld failure on the Target

2014

J-PARC had a trouble on a mercury target in the end of April 2015. Tiny water leak occurred at a weld joint on the target.

SNS future plans – 2nd target station

• Plan to add a second target station
• Not funded yet, but project could start soon
• Have baseline design, Technical Design

Report

• Working toward start of CD-1 preparations

Fermilab Accelerator Complex in PIP

H- linac : accelerates H- to 400 MeV Booster : 4.2×1012 protons, 400 MeV  8 GeV at 7.5 Hz, h=84 Recycler: a permanent magnet accumulator ring in the MI tunnel Main Injector: 8 GeV 120 GeV at 1.33 s cycle time, h=588 ( 7*84) 2+6 booster batches are injected to MI using slip-stacking Simultaneous operations of NOvA and SY120 (slow extraction beam) Courtesy of S. Nagaitsev

0.5 sec. Revolution time of Recycler

Beam power history for NuMI

MI only RR 6-batch RR 2+6-batch

Shutdown for the PIP; Recycler upgrade

• installed Booster-to-RR and RR-to-

MI transfer lines

• new rf system, transverse dampers
• instrumentation upgrades

MI upgrade

• 2 more cavities,
• quad. power suppy..

Installation of 700 kW target /horns

On-going upgrade for 700 kW NOvA

• Factor 2 increase in repetition rate ( 7.5  15 Hz ) of the booster by

rf cavity refurbishment and tuner cooling upgrade

• Loss reduction/mitigation in the Booster
• 6+6 slip stacking in RR

 700 kW by February 2016 Testing 4+6 operation green line shows beam in the Recycler

PIP-II

Performance Parameter PIP-II Linac Beam Energy 800 MeV Linac Beam Current 2 mA Linac Beam Pulse Length 0.5 msec Linac Pulse Repetition Rate 20 Hz Linac Beam Power to Booster 13 kW Linac Beam Power Capability (@>10% Duty Factor) ~200 kW Mu2e Upgrade Potential (800 MeV) >100 kW Booster Protons per Pulse 6.4×1012 Booster Pulse Repetition Rate 20 Hz Booster Beam Power @ 8 GeV 120 kW Beam Power to 8 GeV Program (max) 80 kW Main Injector Protons per Pulse 7.5×1013 Main Injector Cycle Time @ 120 GeV 1.2 sec LBNF Beam Power @ 120 GeV* 1.2 MW LBNF Upgrade Potential @ 60- 120 GeV >2 MW

Goal: Provide >1 MW at the time of LBNF startup (~2023) 800 MeV superconducting pulsed linac + enhancements to existing complex

PIP-III

P I P - I I I “ m ul t i

• M W ”
• O pt

i

• n

A 8 GeV SRF Linac =0.838 120 GeV Main Injector 8 GeV Recycler >2-MW target P I P - I I I “ m ul t i

• M W ”
• O pt

i

• n

B ~2=0.8+1.2 GeV SRF Linac New 8 GeV RCS

(or “greatly upgraded” Booster?)

120 GeV Main Injector 8 GeV Recycler >2 MW target P I P - I I I “ m ul t i

• M W ”
• O pt

i

• n

C 800 MeV SRF Linac new 8-12 GeV “smart” RCS i

• Booster

120 GeV Main Injector 8 GeV Recycler ? >2 MW target

From “High Power Proton Beams for Particle Physics ” Sergei Nagaitsev, 11th ICFA seminar on Futre Perspective in High Energy Physics

ISIS synchrotron

Injection Energy 70 MeV Extraction Energy 800 MeV Injection scheme H- Charge Exchange Circumference 163.36 m Repetition 50 Hz Total beam power 0.2 MW

The beam is split between TS-1 and TS-2, 40 pps to TS-1 and 10 pps to TS-2. Typical beam powers on each targets are 0.16 MW to TS-1; 0.032 MW to TS-2

Courtesy J. Thomason

0.8-3.2 GeV RCS 0.8-3.2 GeV FFAG

Upgrade and future plans of ISIS

TS-1 upgrade (~2019)

• A newly optimized solid plate tungsten target, modulator and reflector are planned
• Beam power is 0.16 MW as before,

but expected to give at least 2 times larger neutron flux on every instrument

• Also smaller incremental steps possible

ISIS II – Next Generation Short Pulse Source (new machine)

• Study options e.g. 1-10 MW flexible, upgradable, multi-target facility
• Present ideas based on 5 MW RCS or FFAG (studies with ASTeC Intense Beams Group)

Courtesy J. Thomason

Accelerator development and upgrade plans Upgrade of existing machine

• Extensive studies of 180 MeV injection

into the existing ring – would give 0.5 MW

J-PARC

N eut ri no beam s t

• S K

Ｍ Ｍ Ｒ Ｒ H adron experi m ent al hal l M LF ( M at eri al and Li f e sci ence experi m ent al Faci l i t y) R C S Li nac

• 400-MeV H- linac
• 3-GeV RCS with 25 Hz
• 30-GeV MR with cycle time of 2.48/6.0 sec

RCS is proton driver for neutron/muon production in MLF and booster for the MR.

MR has a lattice of imaginary transition  and two extraction modes.

Earthquake

300 kW

Hg-target replacement Incident at Hadron Facility 532 kW

300 kW

• as of 3rd of June 2015

〜560 kW ～10 months interruption due to the earthquake 593 kW ～1 month interruption due to the fire in MLF

Beam Power History at MLF

Interruption due a trouble

• f Hg-target

500 kW 400 kW

Time (ms)

Number of particles / pulse (x1013)

Demonstration of 1 MW-eq. beam

8.41 x 1013 :1010 kW-eq. 6.87 x 1013 :825 kW-eq. 4.73 x 1013 :568 kW-eq. 7.86 x 1013 :944 kW-eq. 5.80 x 1013 :696 kW-eq.

2015/1/10

Reinforcement of the anode power supplies of the rf power amplifiers is planned in 2015 summer shutdown periods. After the reinforcement, 1-MW user operation will start within this JFY.

BLM signal (a.u.)

Collimator section First arc section (near the dispersion peak)

Mainly from foil scattering during injection

8.41 x 1013 6.87 x 1013 4.73 x 1013 7.86 x 1013 5.80 x 1013

Time (ms)

BLM signals @ collimator & arc sections

Longitudinal beam loss

50 100 150 200 250 300 350 400 2010/01/01 2011/01/01 2012/01/01 2012/12/31 2014/01/01 2015/01/01 MR Beam Power (kW) Date

MR Beam Power

History of MR beam power

Delivered beam power is 360 kW for the T2K experiment. Total number is > 1.1x1021 POT as of June 3.

Slow extraction operation in April, 2015

After the long shutdown for 1 year and 11 months due to the radioactive material leak incident, beam operation resumed for users in the hadron experimental facility.

2 2

Power upgrade plan of MR

JFY 2014 2015 2016 2017 2018 2019

Event

• Li. current

30 -> 50 mA

FX [kW] (study/trial) SX [kW] (study/trial) 240-320

• >350

24~50 ~400 >50 >400 50~100 ~750 ~100 >750 100 Period of magnet PS New magnet PS 2.48 s 1.3 s Present RF system High gradient rf system Ring collimators

Back to JFY2012 (2kW)

• Add. colli.

C,D

• Add. colli.

E,F

Injection system FX system SX collimator / Local shields Ti ducts and SX devices with Ti chamber Beam ducts ESS

R&D Mass production Kicker PS improvement, Septa manufacture /test Kicker PS improvement, LF & HF septa manufacture /test Local shields

FX: The high rep. rate scheme is adopted to achieve the design beam intensity, 750 kW.

• Rep. rate will be increased from ~ 0.4 Hz to ~1 Hz by replacing magnet PS’s and RF cavities.

SX: After replacement of stainless steel ducts to titanium ducts to reduce residual radiation dose, 50 kW operation for users will be started. Beam power will be gradually increased toward 100 kW carefully watching the residual activity. Local shields will also be installed if necessary.

Manufacture, installation & test

Low cost R&D New power supply Buildings

Feasibility of the RCS

RCS intensity Loss Loss power at 25 Hz 1.0 MW ~0.3% 400 W 1.1 MW ~0.3% 440W 1.2 MW ~0.3% 480 W 1.3 MW ~0.3% 520 W 1.4 MW ~0.3% 560 W 1.6 MW ~0.5% 1067 W 1.8 MW ~0.7% 1680 W 2.0 MW ~1.5% 4000 W

Loss (%)

Injection beam parameters: Energy : 400 MeV Peak current : 50 mA~100 mA Pulse length: 0.5 ms Chopper-beam on duty : 0.53

Beam intensity

RCS collimator limit ~4 kW → RCS has a feasibility to operate 2 MW

• Linac 100 mA/0.5 ms (50 mA/1.0 ms) operation is required.

R&D of ion source / long pulse operation of linac

• The rf system should be replaced to compensate a heavy beam loading.
• The collimator capability should be upgraded to get a margin for the beam loss.
• Activation downstream of the charge exchange foils should be reduced.

….

Beta & Dispersion for 1-superperiod

x,y (m) x,y (m)

H & V

s (m)

The 8-GeV booster ring

(x,x’) (y,y’) @ 3GeV @ 8GeV >125.5 ~0.04% >54 ~0.06% Phase plot @ inj.(3GeV) & extr.(8GeV)

• 0.2
• 0.1

0.1 0.2 0.3 0.4 0.5 0.6 0.7 20 25 30 35 40 45 50 MS00 MS10 MS20 KM01 2.36 mrad KM02 2.36 mrad KM03 2.36 mrad Collimator QFP004 QDT005 QFR006 QDR007 BP01 BP02 ZSH006 Injection Beam 81 pi Baseline design x(m) s(m)

8 GeV injection in the MR using new septa&kickers RCS : 1.6 MW MR > 2.6 MW RCS : 2 MW MR > 3.2 MW

8-GeV BR

INJ+COLL RF CAVs RF CAVs EXT

Injection energy 3 GeV Extraction energy 8 GeV Circumference 696.666 m Superperiodicity 4 Transition gamma ~15 GeV Collimator Aperture 126π.mm.mrad Physical Aperture 189 π.mm.mrad

Accelerator major design parameters

Linac

Project Phase I II Beam Power on target [kW] 100 500 Proton energy [GeV] 1.6 1.6 Average beam current [μA] 62.5 312.5 Pulse repetition rate [Hz] 25 25 Linac energy [MeV] 80 250 Linac type DTL +Spoke Linac RF frequency [MHz] 324 324

• Macropulse. ave current [mA]

15 40 Macropulse duty factor 1.0 1.7 RCS circumference [m] 228 228 RCS harmonic number 2 2 RCS Acceptance [mm-mrad] 540 540

CSNS

Courtesy S. Wang

 Lattice of 4-fold symmetry, triplet.  227.92m circumference.  Four long straight sections for injection, acceleration, collimation and extraction.  24 main dipoles with one power supply.  48 main quadrupoles with 5 power supplies.  Ceramic vacuum chambers for the AC&pulsed magnets.  8 RF ferrite loaded cavities to provide 165 kV.

RCS Design

27

RCS Tunnel is now ready for installation

Magnets and power supplies

24 dipoles and 48 quadrupoles for RCS have been fabricated and delivered to CSNS. The field measurements for dipoles have been

• completed. For quadrupoles, half of them have

been measured. The first set of the power supply for RCS main magnets is completed and the other 5 sets are under mass production.

The first set of the power supply

Ring rf and vacuum system

The first ferrite-loaded cavity and high power RF source have been successfully manufactured and tested. The remaining 7 sets will be delivered to CSNS site soon.

Ferrite-loaded cavity

RF power supply All 25 ceramic chambers for main dipoles and most

• f ceramic chambers for quadruples have been

fabricated and delivered to CSNS site. TiN coating have been started for the ceramic chambers. Dipole ceramic chamber under vacuum check Newly invented RF cage

2 bump power supplies have been manufactured and tested with dummy load. The prototype kicker power supply has been upgraded, and tested. Based on the upgraded design, mass production has been started.

Pulse power supplies, beam diagnostics and control

Power supply for bump magnets. Power supply for kicker magnet.

The fabrication and test of diagnostics and control components are on schedule. Test of BLM in a proton cyclotron

High luminosity colliders

Past, present, future of energy frontier

FCC-hh16T magnets)

Courtesy of O. Bruning

Energy frontier should be a global project because of the ambitious scope, high cost, huge manpower, and long R&D time. It needs more long time to realize than the accelerators in the past.

LHC

Linac 0 - 50 MeV PSB 0.05 - 1.4 GeV PS 1.4 - 26 GeV SPS 26 - 450 GeV LHC 0.45 - 7 TeV

CERN proton accelerator chain

HL-LHC LHC Injector Upgrade (LIU)

RUN 1 : Integrated luminosity ~ 30 fb-1 2010: Commissioning Integrated Luminosity ~ 0.04 fb-1 CM energy ~7 TeV 2011: .. exploring limit Integrated Luminosity ~ 6.1 fb-1 CM energy ~7 TeV 2012: .. production Integrated Luminosity ~ 23.3 fb-1 CM energy ~8 TeV

From “LHC upgrade: High Luminosity” Frederick Bordry, 11th ICFA seminar on Futre Perspective in High Energy Physics

LHC luminosity goals

2015 : 10 fb-1 RUN2: ~100 -120 fb-1

RUN1 RUN2 RUN3

LIU in LS2:

• Linac4 replaces Linac 2.
• H- injection and increase PSB injection energy 50 160 MeV
• New rf system for PSB (collaboration with J-PARC)
• Increase PSB extraction energy 1.4 2 GeV
• Increase PS injection energy 1.4 2 GeV
• Transverse resonance compensation in PS
• New RF Longitudinal feedback system in PS
• Electron Cloud mitigation in SPS
• Impedance reduction, improved feedbacks in SPS
• Large-scale modification to the main RF system in SPS

RUN4 RUN5

Goal of 3,000 fb-1 by mid 2030ies 300 fb-1 before LS3

Courtesy of O. Bruning

KEKB to SuperKEKB

KEKB: 1998 — 2010

Design luminosity 8 x 1035 cm-2s-1

Peak luminosity 2.1 x 1034 cm-2s-1

SuperKEKB

35

40 times higher luminosity 2.1x1034 --> 8x1035 cm-2s-1 Nano-Beam scheme extremely small y

*

low emittance Beam current double

New e+ Damping Ring

e- :7 GeV, 2.6A e+ :4 GeV, 3.6A

L   2er

e

1  y

*

 x

*

      Iy y

*

RL Ry      

Redesign the lattice to squeeze emittance (replace short dipoles with longer ones, increase wiggler cycles) Upgrade Belle II detector

SuperKEKB

Collision Point

Reinforce RF systems for higher beam currents Upgrading (LER) and new (HER) wiggler sections Replace beam pipes with TiN-coated beam pipes with antechambers New superconducting final focusing magnets near the IP Magnets installed for DR  Low emittance RF electron gun  Upgrade positron capture section

JFY2010 Dismantle KEKB

KEKB

• peration

SuperKEKB construction SuperKEKB

• peration

Startup, Conditioning, etc

SuperKEKB master schedule

JFY2011 JFY2012 JFY2013 JFY2014 JFY2015 JFY2016 JFY2017 For about 10 years QCS install Belle II roll in Phase 1 Phase 2, 3 ・・・ ・・・ DR

Challenges for high power beam operation

• Mainly experience in J-PARC synchrotrons -

High power charge stripping

RUN # Beam power [kw] Painting condition Average foil hit number #57-60 300 100  37.5 #61 300 to 400 100  37.5 #62 400 to 500 150  18.4

–2014/10/22 (12:00:31)

#57

–2014/11/03 (00:00:30)

#58

–2014/11/26 (00:00:22)

#59

–2015/01/05 (09:54:04)

#60

–2015/02/19 (03:00:00)

#61

Experience of J-PARC RCS in the routine operation with 300 - 500 kW

4x10

18

3 2 1

injection particle

2014/10/01 2014/11/01 2014/12/01 2015/01/01 2015/02/01 2015/03/01 2015/04/01

RUN 57 - 62

4x10

21

3 2 1

total inj. particle

RUN57 RUN58 RUN59 RUN60 RUN61 RUN62

Accumulate particles from Linac Beam Power [kW] 300 [kW] 400 [kW] 500 [kW] HBC (Hybrid Boron doped Carbon Thickness：340μg/cm2 Irradiation history: Start： November 22th 2014 Total dose @April 18th 2015

• Number of injection particles :

4.40x1021

• Number of total particles pass

through the foil (including circulating particles at RCS)：1.56x1023

High power charge stripping (cont’d)

Innovative methods like laser stripping are developed for the future much higher beam power.

Experience of SNS ( > 1.2 MW )

• Damaged by reflected convoy

electrons when power >1.2 MW

• Designing new brackets
• Plan to redesign electron collector

Courtesy M. Plum

ID Trans.-paint ( mm mrad) RF V2/V1 (%)  (deg) dp/p (%) 1

• 2

100

• 3
• 80
• 100
• 0.0

4

• 80
• 100
• 0.1

5

• 80
• 100
• 0.2

6 100 80

• 100
• 0.0

7 100 80

• 100
• 0.1

8 100 80

• 100
• 0.2

Painting beam injection in J-PARC RCS

○ Einj=181 MeV, 540 kW-eq. ○ Einj=400 MeV, 553 kW-eq. ○ Einj=400 MeV, 553 kW-eq.

Beam intensity (x1013) Einj=181 MeV Einj=400 MeV Time (ms)

Collimator and beam loss localization

Collimators plays an important role to reduce uncontrolled beam loss and keep low residual radioactivity for hands-on maintenance.

by Roderik Bruce, CERN LHC from WS at ESS Lund, May 2014

LHC Collimator system:

• LHC has separate insertions for betatron and

momentum cleaning.

• In total about 100 collimators.

J-PARC MR

Space charge

Space charge can limit performance of high intensity synchrotrons. For high power beam operation, it is necessary to avoid betatron resonances in the presence of space charge tune shift .

• resonance correction
• large bunching factor

J-PARC MR :

• Power 310 kW
• Number of protons: 2e13 ppb
• Transverse Emittance: 12π mmmrad
• Bunching Factor: 0.25
• Space Charge Tune Shift: 0.4

  2RNr 4 2 / (v / c)2 3Bf  0.4

Correction of linear coupling resonance with skew quadrupoles in J-PARC MR

(22.41, 20.76)

SQs OFF SQs ON

Skew-Q off ---

• n ---

Number of protons ( x1013 ppp) Two bunches, 3-GeV accumulation (not accelerated) 4.0 6.0 SQs reduces the beam loss > 1kW for 330 kW beam operation.

Space charge (cont’d)

This correction makes possible to adopt higher vertical tune to reduce the effect of the half-integer resonance. Correction of third-order resonances with trim sextupoles in J-PARC MR

Trim-SFA048 = 0.3 A To correct Qx+2Qy=64

Number of protons ( x1012 ppb)

Space charge (cont’d)

2nd harmonic RF voltage in J-PARC MR

(V1, V2) = (100 kV, 0 kV) Bunching factor is increased by the 2nd rf voltage (V1, V2) = (100 kV, 36 kV) Beam survival ratio for 360 kW operation

2nd on 2nd off

Space charge (cont’d)

Feedback system for suppression of beam instability

Transverse instabilities are observed at the injection and the beginning of acceleration at the MR. The instabilities are suppressed by the bunch feedback systems.

BxB FB since 2012

Acceleration start 4 times beam injection

400 ms

Intra-bunch FB since 2014

Without FB BxB on intra-B on

Feedback ON Feedback OFF

Bunch signal at 100 turns

Feedback ON Feedback OFF

Without FB BxB FB on intra-bunch FB on

Oscillation of one bunch slice

Head-tail Instabilities in ISIS

In the ISIS synchrotron, the head-tail beam instability causes beam loss at 2

• ms. It limits the beam intensity for the operation.

Courtesy J. Thomason

BPM electrode sum (top), difference (bottom) Head Tail Instability Signal

Injection, capture, head tail loss A new beam feedback system to damp the instabilities is under development.

Reliability and residual activation for proton facilities

• S. Cousineau, “High Power Proton Facilities: Operational Experience, Challenges, and the Future”, Proc. IPAC2015

Synchrotron and rings have much higher residual activation. But they should be improved by better understanding beam loss mechanism and reducing uncontrolled beam losses in spite of beam intensity increasing.

Acknowledgements

Thanks all the contributors;

• M. Plum (SNS)
• J. Thomason, Chris Warsop (ISIS)
• M. Convery , S. Nagaitsev (FNAL)

Sheng Wang (CSNS)

• O. Bruning (CERN)
• K. Akai, H. Koiso (SuperKEKB)
• S. Igarashi, M. Kinsho, H. Harada, H. Hotchi, Y. Irie, F. Naito, Y. Sato, M. Shirakata, J.

Takano, F. Tamura, T. Toyama (J-PARC)

Backup

New Proton Driver in the KEKB Tunnel

KEKB tunnel:

• fourfold symmetric configuration.
• Circumference: ~ 3 km
• Straight section： beam acceleration

200 m x 4 = 800 m

• Arc section： beam transportation to

the next straight section. 550 m x 4 = 2200 m Feasibility of 9 GeV proton linac in straight sections of 800 m. ⇒ High acceleration field is required. ⇒ ILC cavity is adopted. We start discussion as one of the post-Super KEKB project.

Outline of the Proton Driver using ILC Cavity

1.2 GeV 3.3 GeV 6.2 GeV 9 GeV 1.3 GHz g = 1.0 1.3 GHz g = 1.0 1.3 GHz g = 0.93 9 GeV

• Outline of acceleration :
• 1.2 GeV in 1st straight.
• 3.3 GeV in 2nd straight.
• +2.9 GeV in 3rd and 4th straight.

3.3 + 2.9 x 2 = 9.0 GeV

• Peak current : 100 mA (pulse)
• Beam duty : 1 %
• Beam power :

9000 MeV x 0.1 A x 1 % = 9 MW

• βg of SC cavities :
• 2nd straight

: βg = 0.93

• 3rd and 4th straight: βg = 1.0
• Normalized RMS emittance
• Transverse

: 0.30 π・mm・mrad

• Longitudinal : 0.37 π・MeV・deg

To Kamioka

650 MHz rebuncher x 3 1.3 GHz rebuncher x 3 1.3 GHz rebuncher x 3

55

PB1 ,2 PB3 ,4 QF L Q DL SB 1 SB 2 SB 3 SB 4

x

ISEP 1,2

1st foil

s

MWPM3 MWPM4 MWPM5 2nd foil 3rd foil

H- H- H0

Circulating beam

H+

H- H0

H+

• depress beam

density

• decrease foil

Beginni ng of paintin g End of paintin g

Painting injection <Injection scheme>

• Chopped beam
• H－charge

exchange

• 307 multi-turns

(400MeV)

2015/03/21

“Painting injection”

Transverse painting injection

Horizontal painting: by a horizontal closed orbit variation during injection Vertical painting: by a vertical injection angle change during injection Transverse painting makes use of a controlled phase space offset between the centroid of the injection beam and the ring closed orbit to form a different particle distribution of the circulating beam from the multi-turn injected beam.

Typical painting emittance is tp= 100 – 150  mm mrad

• H. Hotchi

Transverse painting injection (cont’d)

No transverse painting 100 correlated painting Horizontal Vertical

Numerical simulations Transverse beam distribution just after the beam injection (at 0.5 ms)

• H. Hotchi

Longitudinal painting injection

Longitudinal painting makes use of a controlled momentum offset to the rf bucket in combination with superposing a second harmonic rf to get a uniform bunch distribution after the multi-turn injection. Momentum offset injection

p/p=0, 0.1, 0.2%

RF voltage pattern

Uniform bunch distribution is formed through emittance dilution by the large synchrotron motion excited by momentum

• ffset.

The second harmonic rf fills the role in shaping flatter and wider rf bucket potential, leading to better longitudinal motion to make a flatter bunch distribution.

Fundamental rf Second harmonic rf

V2/V1=80%

• H. Hotchi

Longitudinal painting injection (cont’d)

V2/V1=0

Vrf=V1sinV2sin{2(s)+2} Phase sweep of the second harmonic rf

2=100 deg 2=50 deg 2=0

The second harmonic phase sweep method enables further bunch distribution control through a dynamical change of the rf bucket potential during injection.

Additional knob in the longitudinal painting ; phase sweep of V2

2=100 to 0 deg

V2/V1=80%

Longitudinal painting injection (cont’d)

No longitudinal painting V2/V1=80% 2=-100 to 0 deg p/p= 0.0% V2/V1=80% 2=-100 to 0 deg p/p=-0.1% V2/V1=80% 2=-100 to 0 deg p/p=-0.2%

Measurements (WCM) Numerical simulations Longitudinal beam distribution just after the beam injection (at 0.5 ms) Bunching factor : ~0.15 ⇒ >0.4

Bf=0.15 Bf=0.40

Wiggler magnets Nikko-side (L-side) of IR Beam pipes installed in Tsukuba IR area (Nikko side)

IP Arc

Horizontal type collimator

e- e+

6 ARES cavities in D5 relocated from HER to LER 6 ARES cavities in D5 relocated from HER to LER

Construction of Main Rings

Interaction Region (IR)

Iron support and concrete floor already set at IP for Phase 1 Beam pipes at IP

Additional shielding walls will be constructed in Oct. 2015. IR cover and large gate concrete shields will be set to IR in autumn 2015.

Wiggler magnets Nikko-side (L-side) of IR Beam pipes installed in Tsukuba IR area (Nikko side)

IP Arc

Horizontal type collimator

e- e+

6 ARES cavities in D5 relocated from HER to LER 6 ARES cavities in D5 relocated from HER to LER

Construction of Main Rings

Completed ESL compensation

• solenoid. The solenoid was

divided into 12 small solenoids.

Assemblies of the quadrupole magnets and corrector magnets are progressing for the construction of the QCSL cryostat.

Final Focus Superconducting Mangets (QCS)

Damping Ring

• Construction status

– Construction of the tunnel and buildings was completed. – Magnet installation was completed for the beam transport lines (LTR and RTL). – Installation of high power cables in the ring was completed. – All power supplies for the magnets were delivered. (except for steerings) – Beam pipes for the arcs were delivered and TiN coating is going on. – Beam pipes for straights are in fabrication. – Two RF cavities have been fabricated. Results of HP test exceeded specifications.

• Plan

– Installation and startup work continues in JFY2015. – Commissioning of DR will start in JFY2016 in the transition period between Phase 1 and 2.

Cross section Antechamber-type beam pipe for arcs Magnets in tunnel Cross section DR RF cavity Magnets in LTR