2007/2/111 A Report to the Advisory Committee of CNS The Accelerator Group Outline Progress in April – December 2006 Schedule in Jan. 2007 – March 2008.

2007/2/11 1

A Report to the Advisory Committee of CNS The Accelerator Group

•Outline

•Progress in April – December 2006

•Schedule in Jan. 2007 – March 2008

Upgrade of AVF Cyclotron

Shigeru Kubono, Yukimitsu Ohshiro, Shin-ichi Watanabe. Syoichi 　 Yamaka(CNS)

Sergey B. Vorozhtsov, Alexey S. Vorozhtsov, Evegeny E. Perepelkin (JINR)

Akira Goto, Masayuki Kase (RIKEN)

Toshinori Mitsumoto (SHI), Mitsuhiro Fukuda (RCNP)

2007/2/11 2

１０１０ GHGHｚｚECRECR

Layout of AVF Cyclotron

HyperECR

AVF Cyclotron

Room E7

Rext=0.714m

Bmax=1. 7 T

Vrf = 50 kV

h =2

F0=12~24MHz

FC-I36FC-C01a

FC-I10

Cycro center

FC-F0CRIB

2007/2/11 3

K-value 70 MeV M/Q2

Acc.Beam 14N5+ 8.4 MeV/uAverage Max.field 17 kGExtraction radius 714 mmDee angle 83°x2 DeesVoltage peak 50 kVRF frequency 12-24 MHzRF power 2 x 50 kWMain coil power 180 kW (1100 A)Circular coil 8 pairsHarmonic coil 4 pairsVacuum pump 1500 l/s TMP x1

4000 l/s CRYO x18500 l/s CRYO x1

Manufactured 1989

Specifications of RIKEN AVF

2007/2/11 4

１９９７

１９９８

１９９９

２０００

２００１

２００２

２００３

２００４

２００５

２００６

２００７

HyperECR

Improve

SF ECR BT

Charge breeder

AVF Flat top

High power RF

Main & Trim coil

Center region

Improvements

Beam line

E7(CRIB)

SF clean up

PA

Monitor

DCCT

Cluster

Rf buncher

VIS

JSPS foundation

Atomic　Physics

10 years over view

Cold model hot model Tuning Beam test Operation

K=80

InstallationMove to RIKEN Operation

Design

Monitor

R&D

Modify

Improvement

DesignH=2,3 H=1

Deflector

CRIB

Sputtering

Ion source

Mesh

Move to RIKEN

HiECR

Accel-decel

Metal ions

Insulator Condenser

F0 focus

Contribution to AVF upgrade

Metal IS

Glaser lens

Insulator

VIS

Sputtering ISRf buncher

SQUID monitor

2007/2/11 5

Directivity of upgrade of the RIKEN AVF cyclotron (K70) *The advancement which aimed at the beam performance needed for Nuclear Astrophysics research.

①High energy by K value reinforcement (acceleration h = 2) →　Main coil & trim coil power supply reconstruction

②Extension of an acceleration energy domain 　

(Acceleration harmonics h = 1, 3) →　 Center region reconstruction

High Energy by K80,15N5+ 9MeV/u, 10pA

Acceleration harmonics h = 1, 2, 3

Energy per Nucleon (MeV/u)

磁場

(T

)

15 60

ｈ＝１center region

42

②

ｈ＝２　 (K-value ）

Now in used

①

②

ｈ＝３center region

The main point of AVF Upgrade

2007/2/11 6

What is advanced in 2006?1. Ion source HyperECR Ion source / Metal ions 　 New ion source /Charge breeder ECR, Super ECR 2. Development of AVF Cyclotron Glaser lens New AVF control room / Shared RIBF space Dee RF / up to 52 kV

3. Upgrade of RIKEN/CNS AVF cyclotron Design study of B-field, E-field, Centering, Inflector, Dee

chips, RF-shield, Injection, Extraction, Beam losses　　

2007/2/11 7

1. Ion Source

A. Hyper ECR

The half of the machine schedule of RIKEN cyclotron uses the our HyperECR ion source.

B. Metal Ion Source

Si, Ca, P extracted from HyperECR

C. Super ECR

5.5K is continued

D. CBECR

Under the setup and vacuum test

Y. Ohshiro

2007/2/11 8

Ion Energy C10 C01/I36(MeV/u) (eA) (%)

H+ 14 9.1 11

H2+ 3.97 2.8 8.236Li3+ 9.5 1.55 2.67Li2+ 3.4 3.7 3.712C4+ 7 1.3 3.313C4+ 5.54 6.2 18.214N6+ 8.2 5.2 34.715N4+ 5 3.8 4.818O5+ 3.89 2.5 9.618O6+ 6.27 5.2 14.420Ne7+ 7 0.77 10.722Ne７+ 6.25 4.6 35.483Kr23+ 5.45 0.033 4.5

★Extracted beam from AVF cyclotron○The typical beam intensity in this year (2006) is shown in the Table 1. ○Beam transmission efficiency of ECR-AVF cyclotron (C01/I36) 35% is realized. ○The half of the machine schedule of RIKEN cyclotron uses the our HyperECR ion.source.

★Metal ion○ Since the hot liner in the plasma chamber is attached, Li ion generation which used crucible can be stable and can take out the ions of large intensity.○By having doubled the capacity of crucible, sample use time for one week or more was realized.

A. Hyper ECR Ion SourceTable 1

Y. Ohshiro

2007/2/11 9

Second stageECR zone

First stageECR zone

⑦ ⑥

④③②

Center

①

⑤

⑧

Fig. 2. The distance of the tips of the crucible and the rod placed in the plasma chamber.

Table 2. Beam intensities of metallic ions obtained Ion Beam Intensity Charged Material

(eA)7Li3+ 75 Li pure metal (crucible)7Li2+ 200 Li pure metal (crucible)28Si9+ 32 SiO2 (rod)

40Ca11+ 50 CaF2 (rod)31P9+ 29 P2O5 (Crucible)

B. Development of Metal Ions

★Sample insertion optimum position ○When a crucible or a rod is placed near 1st ECR zone with efficient consumption rate, the metal ions of large intensity is obtained. ○The metal ions which can be used now is shown in Table 2.

ECR

Bz　(kG)

Thi

s ye

ar

Y. Ohshiro

Fig. 1 Schematic drawing of Hyper ECR ion source together with mirror field distribution used for 40Ca11+ ions production.　① Plasma chamber, RF wall, Solid ② ③material, Movable rod, Sextupole magnet, MC1, ④ ⑤ ⑥

MC2, Extractor⑦ ⑧

2007/2/11 10

C. Development of SC-ECR Ion Source

★Purpose. Extraction of multicharge ion beam reinforcement by AVF cyclotron. 　For example, since an Ar11+ ion beam is 100eA, compared with HyperECR, an about 3 times as many increase as this is expected. * Present condition. O It installed on the test bench of RIBF-B1. O Electric power and cooling water were fixed. O The freezer was overhauled. O The cooling test of a superconductivity wire was completed. O Cooling temperature is stable at 5.5 k. O A mirror coil power supply is under manufacture.

Fig. 3. The superconductivity ECR ion source installed by the test bench at RIBF-B1 (SC-ECR)

Y. Ohshiro,

Tsukuba Univ.

2007/2/11 11

* Purpose. 1) Inject Ar+ to CBECR, and generates Ar11+ of large intensity. 2) Inject the metal ion from the external metal ion source, and generate the metal ion (Li, etc) of large intensity. * The feature. 1) More than Ar+ 10eA incidence. 2)Large differential pumping system because of an improvement of the vacuum pressure. 3) Strengthening of slowdown efficiency. * Present status. 1) Under an setup end and a vacuum test. 2) Source test; end of the volume type ion source = 40Ar+ 100 eA O sputtering type ion source; Test end. 　　 Al+=66 [enA], Li+=2 [enA]. .

Fig. 4. The charge breeder attached in the

electromagnetic analyzer

D. Development of CNS Charge BreederY. Ohshiro

2007/2/11 12

①

②③

④

⑤

14GHz RF

⑥⑦⑧

TMP1 TMP2 TMP3

0 20cm

E2 E3 E4

Deceleration Acceleration

Incident beam energy (10 keV +5 eV)

ΔV

0Voltage [kV]

Fig. 5. A cross-sectional view of the CNS charges breeding system and potential map for injection of interest ions. Volume ①type ion source, Insulator (MC ②④nylon), Einzel lens (E③ 1-4), Charge ⑤breeder ECR ion source (CBECR),

Plasma chamber, Decelerator, ⑥ ⑦Conical wall.⑧

E1

Table 3. Specification of each device 　　 designed.

First stage ion source (IS)

・Volume type IS E.g. Ar+, 15N+ production

・Spattering type IS E.g. Li+ - Cu+ production

・Extraction voltage 10 kV + 5 VBeam transport system・Max. Einzel lens voltage 20 kV (E1 - E4)

・Deceleration voltage 10 kVCharge breeder ECRIS ・RF frequency 14 GHz ・Max. Mirror field 12 kG

・Surface field of sextupol 10.4 kG・Correction coil 13500 AT (C1 - C3)

・Acceleration voltage 10 kV

Y. Ohshiro

Charge Breeder (continued)

2007/2/11 13

2. Development of AVF in 2006 Glaser Lens

•Old Glaser lens was damaged by coil trouble

•New Glaser lens 'GLI38' is installed.

New Glaser lensPull out the old lens

S. Watanabe

2007/2/11 14

2. Development of AVF in 2006

Glaser Lens (continued )

MCI vs GLI

0

50

100

150

200

250

300

350

0 200 400 600 800 1000 1200

MCI (A)

GLI (

A)1系列2系列3系列4系列

Beam focusing power is improved up to 2 times (F B∝ 2)

With New GLI38 With Old GLI38

Magnetic Field of Glaser Lens

S. Watanabe

Mag

neti

c field

(G

auss

)

Distance from medium plane

GLI38 (Imax)

GLI37 (Imax)

Performance of GLI38

GLI37

GLI38New / Old

Main coil current (A)

Gla

ser

lens

curr

ent

(A)

2007/2/11 15

2. Development of AVF in 2006Beam Extraction

•Magnet channel and Deflector chips are improved. •Extraction efficiency is confirmed by using 14N6+ 8.2 MeV/u.

I645

I825

~ 97% obtained

I825 /I645

8.2 MeV/u, Iecr=17eA,

I645=4.1eA, I825=4.0eA

I825 ; after magnetic channelI645 ; Before deflector entrance

Goto/Kubono

2007/2/11 16

Beam Extraction (continued)Transmission efficiency of ESD, I825 /I645, is optimized by changing the Deflector

Chip & Magnetic Channel to new one’s. The of 97 % was then obtained when ECR

current is 17 eA*1. The ratio of A/rN. in proportional to is evaluated as follows.

SF PSI TRIUMF

AVF

Te (MeV) 42 (p) 590 (p) 520 (p)

114.8 (14N6+)

Rext (m) 0.73 4.45 7.8 0.714

rN (mm) 0.98 3.9 1.3 3.05/3.07*2

(mm mrad) 10 5 5 16 11 5

A (mm) 3.8 3.7 5.2 3.36/3.52*2 2.78 1.9

A/rN 3.9 0.95 2.4 1.10/1.17 0.91 0.6

rR qnV

TNext

e e

d

e

1

ARext

n=number of Acc. Gap=4

Vd= Dee voltage=45kV

Table. Calculated A/rN

A = beam envelope at Rext , rN = Turn separation at Rext

ecr e

*2=measured by main probe

*1 Data; Nov. 28, 06 R&D, Dec. 11, 06 Exp. 8.2 MeV/u, Iecr=17eA, I645=4.1

eA, I825=4.0eA. Beam emittance, ECR, of 110 mm mrad to be taken into account A/rN., is derived from former Exp at E=6.4 MeV/u.

Details of parameters

2007/2/11 17

3. Upgrade of RIKEN/CNS AVF cyclotron - Subjects

1. TOSCA model construction Magnetic field calculation Electric field calculation

2. Study of Beam dynamics (examples) AVF beam dynamics modeling in the 3D E-map

Bunch acceleration from the inflector exit to the final energy

Optimization perspectives

Transmission increase, beam quality improvement

3. Report / Proposal /Schedule Report to RIKEN/CNS from Accelerator group

Proposal of New Inflector, RF shield, Dee chips for h=1, 3

2007/2/11 18

1. TOSCA model constructionAVF magnetic field

►Field at the surface are Field at the surface are compared with measurements compared with measurements in the radial range 0-75cmin the radial range 0-75cm..

In the first stage, mesh model is generated from the drawings. In the second stage, corrective mesh model has been made on the basis of measurement.

A.S. VorozhtsovA.S. Vorozhtsov

The optimizations of remaining differences in the simulations and measurements are still in progress.

2007/2/11 19

1. TOSCA model construction AVF Electric Field

Central region modelCentral region model Acceleration region modelAcceleration region modelNumber of nodes = 3.2 million.Number of nodes = 3.2 million.

grid size in the very grid size in the very center is less than 1 center is less than 1 mmmm

A.S. VorozhtsovA.S. Vorozhtsov

2007/2/11 20

1. TOSCA model construction Acceleration region DC-E map

R(150mm-750mm)

A.S. VorozhtsovA.S. Vorozhtsov

2007/2/11 21

1. TOSCA model constructionCentral region DC-E map Rmax=149mm

A.S. VorozhtsovA.S. Vorozhtsov

2007/2/11 22

2. Study of Beam Dynamics　Confirmation of Inflector parameter and Trajectory

B & E fields model are taken into account the beam dynamics calculation. Inflector (center) , RF shield and Dee chips are shown.

A.S. VorozhtsovA.S. Vorozhtsov & & E.E. Perepelkin

2007/2/11 23

2. Study of Beam DynamicsConfirmation of Acceleration parameter and Trajectory

Injected bunched beam is accelerated along with reference orbits

A.S. VorozhtsovA.S. Vorozhtsov & E.E. Perepelkin & E.E. Perepelkin

2007/2/11 24

2. Study of Beam DynamicsFlat-top acceleration

E.E. PerepelkinE.E. Perepelkin

Expanded radial distribution

FT OFF

FT ON

Narrowed radial distribution

ESDESD

2007/2/11 25

3. Report / Proposal /Schedule• Resume of the RIKEN/CNS AVF cyclotron

upgrade meeting is distributed to the meeting member.

• Presentations at the RIKEN/CNS AVF cyclotron upgrade meeting are distributed to the meeting member.

• Report on Study of h=2 acceleration will be published

• Following meeting will be held in August, 2007.

2007/2/11 26

Summary

• Status of ECR Ion sources HyperECR, Metal IS, Super ECR, Charge breeder are

advanced.

• Development of the AVF cyclotron Axial injection line is improved. Dee voltage and Extraction

efficiency are improved.

• Upgrade of AVF cyclotron TOSCA model of AVF is completed, Beam dynamics model

is advanced, Center region for h=1, 3 is to be proposed. Fine tuning of the TOSCA model is required. electrode, etc.