The SARAF CW 40 MeV Proton/Deuteron AcceleratorRFQ voltage squared vs. forward power 250 300 4-Jul...

The SARAF CW 40 MeV Proton/Deuteron Accelerator

A. Nagler, D. Berkovits, I. Gertz, I. Mardor, J. Rodnizki, L. WeissmanS NRC Y I lSoreq NRC, Yavne, Israel

K. Dunkel, M. Pekeler, F. Kremer, C. Piel, P. vom SteinAccel Instruments, Bergisch Gladbach, Germany

LINAC08, MO203, September 29th, 2008

SARAFSARAF – SSoreq AApplied RResearch AAccelerator FFacilityAAccelerator FFacility

To modernize the source of neutrons atTo modernize the source of neutrons at Soreq and extend neutron based research and applicationsresearch and applications. To develop and produce radioisotopes primarily for bio medical applicationsprimarily for bio-medical applications.To enlarge the experimental nuclear

i i f d hscience infrastructure and promote the research in Israel.

A. Nagler et al., LINAC08, MO203 29/29/2008 2

Accelerator Basic Characteristics

A RF Superconducting Linear Accelerator

ParameterParameter Val eVal e CommentCommentParameterParameter ValueValue CommentCommentIon Species Protons/Deuterons M/q ≤ 2

Energy Range 5 – 40 MeV

Current Range 0.04 – 2 mA Upgradeable to 4 mA

Operation mode CW and Pulsed PW: 0.1-1 ms; rep. rate: 0.1-1000 Hz

Operation 6000 hours/yearOperation 6000 hours/year

Reliability 90%


Maintenance Hands-On beam loss < 1 nA/m

SARAF Layout

RF Superconducting Linear Accelerator Target Hallp g g


A. Nagler et al., LINAC 2006

SARAF project organization

Construction and Commissioning of a (Beyond-)State-of-the-Art accelerator within an international business collaboration

Accelerator – Accel Instruments (Germany)Cryogenics Linde Kryotechnik (Switzerland)Cryogenics – Linde Kryotechnik (Switzerland)Building and Infrastructure – U. Doron (Israel)Applications - Soreq

Overall Integration Soreq

A. Nagler et al., LINAC08, MO203 59/29/2008

Overall Integration – Soreq

SARAF Phase I – Upstream View

PSM

EIS

RFQMEBT

S

EISLEBT


SARAF Phase I – Downstream View

PSM

D-Plate

B D 1Beam Dump 1Beam Dump 2


ECR Ion Source (ECRIS)C Pi l EPAC 2006

Plasma chamber

High voltage

extractor

Magnetic solenoid

Focusingl id

C. Piel EPAC 2006

F. Kremer ICIS 2007

K. Dunkel PAC 2007

beam

Vacuum pump

RF Waveguide& DC-breaker

solenoid

magnetic lipump 5x10-6

mbar

RF power

gcoils on ground

cooling water

gas inlet

p800 W

RF power supply

extraction electrodes

20 kV/u

g1 sccm


20 kV/u

107 mminsulator

LEBT – emittance measurement

C. Piel EPAC 2006

F. Kremer ICIS 2007

magnetic mass

analyzer

FC

K. Dunkel PAC 2007

P. Forck JUAS 2003ECRaperture

wireslitaperture

2003ECR

5 mA proton beam optics


beam optics

RFQ entranceECR

EIS: measured emittance values

ε 100% [π mm mrad]Particles

Beam currentProtons

X / YH2+

X / YDeuterons

X / Y

εrms_norm._100% [π mm mrad]

5.0 mA 0.20 / 0.17 0.34 / 0.36 0.13 / 0.12

2 0 mA 0 13 / 0 13 0 30 / 0 34 0 14 / 0 132.0 mA 0.13 / 0.13 0.30 / 0.34 0.14 / 0.13

0.04 mA 0.18 / 0.19 0.05 / 0.05

Specified value = 0.2 / 0.2 [π mm mrad]


deuterons emittance resultsπ mm mrad2D plot current scale

1 0

3 0

Elliptical Exclusion

0 2

0.25

0.3

Emit. deuterons

2D plot current scale is enhanced in order to present the tail

- 3 0

- 1 0

1 0 x' [mrad]

0.05

0.1

0.15

0.2

Nor

m. R

MS

E

6.1 mAopen

aperture

SCUBEEx Analysis

- 3 0 - 1 0 1 0 3 0- 5 0

x [ m m ]

00 1400 2800 4200 5600 7000

Exclusion Ellipse SAP

B. Bazak

0 06

0.08

0.1

0.12

RM

S Em

it.aperture

1 0

3 0

x' [mrad

JINST 2008

0

0.02

0.04

0.06

0 1400 2800 4200 5600 7000

Nor

m. R cut to

5.0 mA- 3 0

- 1 0

d]


0 1400 2800 4200 5600 7000Exclusion Ellipse SAP- 3 0 - 1 0 1 0 3 0

- 5 0

x [ m m ]

emittance analysis with the SCUBEEx code by M. P. Stockli and R.F. Welton, Rev. Sci. Instr. 75 (2004) 1646

176 MHz Radio Frequency Quadrupole

On site 2006

In factory 2005

P. Fischer EPAC 2006


RFQ commissioning resultsSpecifications in parentheses

Protons Parameter 1.5 1.5 (1.5)(1.5)Output energy [MeV/u]4.0 4.0 (4.0)(4.0)Maximal CW current [mA]

Transverse emittance, r.m.s., normalized, 100% [π·mm·mrad]

0.17 0.17 (0.30)(0.30)normalized, 100% [π mm mrad](at 0.5 mA, closed LEBT aperture)

0.25 / 0.29 0.25 / 0.29 (0.30)(0.30)(at 4.0 mA, open LEBT aperture)

30 30 (120)(120)Longitudinal emittance, r.m.s [π·keV·deg/u](at 3.0 mA)

80 80 (90)(90)Transmission [%] (at 0.5 mA) ( )( )[ ] ( )70 70 (90)(90)(at 2.0 mA)65 65 (90)(90)(at 4.0 mA)6262 (55)(55)R i d RF ( ) [kW]


62 62 (55)(55)Required RF power (protons) [kW]248 248 (220)(220)(deuterons) [kW]

Diagnostic plate (D-Plate) for beam commissioningfor beam commissioning


Proton energy at RFQ exit by TOFBeam Energy Measurement using TOF

between 2 BPMs sum signals, 145 mm apart, E =E = 11..504504 ±± 00..012012 MeVMeV C. Piel PAC 2007E E 11..504 504 ±± 00..012 012 MeVMeV

Button pickup for 2 mA pulse and

15 mm bore radius gives a

signal high above noise.

Bunch width measured atmeasured at

β=0.056 is larger than the predicted value due to the induced charge


induced charge broadening.

Current downstream RFQ vs. RFQ forward power for 3 mA injectionforward power for 3 mA injection

sum of 4 BPM2.5

D-Plate MPCT [mA]

Optimum power for p = 61.5 kW

sum of 4 BPM current signals

2.0

D-Plate_MPCT [mA]

A_MBPM1 [V_p]

A_MBPM2 [V_p]

4D-WB simulation [mA]

MPCT current1.5

m c

urre

nt

4D WB simulation [mA]

0.5

1.0

Bea

m

0.0

0.5

45 50 55 60 65 70 75


45 50 55 60 65 70 75

RFQ power (PS forward) [kW]J. Rodnizki et al. EPAC 2008

RFQ: Bunch profiles measurements

Wire scan profiles0.8

1meanm 0.00 cmFWHMs 0.40 cmFWHMm 0.46 cm

meanm 0.00 cmFWHMs 3.70 cmFWHMm 3.57 cm

M t

C. Piel PAC 2007

0.2

0.4

0.6

coun

ts

32.0 kV

61.5 kW

MEBT Entrance

D-PlateMeasurement

results are backed up by simulations

(TRACK)

-4 -2 0 2 40

position (cm)4 -2 0 2 4

position (cm)1.2

gauss fitsimulated

gauss fitmeasurementFFC1 FFC1

Entrance

(TRACK)

FFC time profiles0.6

0.8

1.0

nt (a

rb.)

simulatedgauss fit

measurement

32.5 kV 63.5 kWSimulation Measured

Rodnizki et al. EPAC 2008

p

0.2

0.4curr

en


EPAC 20080.0

0 100 200 300proton relative phase (deg)

0 100 200 300proton relative phase (deg)

Approximated rms εZ extracted from bunch width measurementsfrom bunch width measurements

75

90ez (RFQ) [pi deg keV]1s at FFC1 [deg]1s at FFC2 [deg]

C. Piel EPAC 2008

60

75 1s at FFC2 [deg]s_f at RFQ [deg]s_E at RFQ [keV]

30

45 Optimum power for p = 61.5 kW

15

30

055 60 65 70 75

power RFQ [kW]


p Q [ ]

Specified rms εZ = 120 120 ππ deg keVdeg keV Value for simulations = 74 74 ππ deg keVdeg keV

RFQ voltage squared vs. forward power

250

3004-Jul9July10J l

080808

200

^2(k

W)

10JulyLinear

08

100

150

Pick

up V

^

0

50

00 50 100 150 200 250 300

FPower (kV)Forward power (kW)


Parting from the linear relation indicates onset of dark current due to poor conditioning

RFQ Conditioning – current statusA few hundred conditioning hours for two yearsA few hundred conditioning hours for two yearsConditioning schemes

Set ma im m po er and increase d t c cleSet maximum power and increase duty cycleSet CW duty cycle and increase power

Special actions to improve conditioning rate:Special actions to improve conditioning rate:Rounding off sharp edges of rods bottom partCleaning of rodsCleaning of rodsInstallation of circuit for fast recovery after sparks

Maximal power reached so far:p195 195 kW CWkW CW280 280 kWkW with duty cycle of 1515%%


75°C baking performed recently for 3 days. Effect on conditioning tp be measured soon

Prototype SC Module (PSM)General Design:• Houses 6 HWR and 3

superconducting solenoids• Accelerates protons and

deuterons from 1.5 MeV/u on• Very compact design in

longitudinal direction• Cavity vacuum and

insulation vacuum separated

A. Nagler et al., LINAC08, MO203 219/29/2008 21M. Peiniger, LINAC 2004 M. Pekeler, SRF 2003 M. Pekeler, LINAC 2006

HWR – Basic parameters

• f = 176 MHz & bandwidth ~ 130 Hz

height 85 cm high• height ~ 85 cm high

• Optimized forβ=0 09 @ first 12 cavities (2 modules)β=0.09 @ first 12 cavities (2 modules)

β=0.15 @ 32 cavities (4 modules)

B lk Nb 3 @ 4 45 K• Bulk Nb 3 mm @ 4.45 K

• Epeak, max = 25 MV/m & Epeak / Eacc ~ 2.5

• Q0 ~ 109

• Designed cryogenic Load < 10 W (@Emax)


HWR measured fields and dissipated power

Closed loop operation with a voltage

At Accel (single cavity) At Soreq (inside PSM)max field limit Q at Q at losses at losses at

Closed loop operation with a voltage controlled oscillator (VCO)

20 MV/m 25 MV/m 20 MV/m 25 MV/m[MV/m] [W] [W]

30 8,0E+08 7,0E+08 3,5 6,3

28 l 2 0E 08 1 4E 08 14 1 31 428 coupler temp. 2,0E+08 1,4E+08 14,1 31,4

32 4,0E+08 2,0E+08 7,0 22,0

29 4,0E+08 2,0E+08 7,0 22,0

31 7,0E+08 4,0E+08 4,0 11,0

29 coupler temp. 7,0E+08 3,0E+08 4,0 14,7

Σ 39,7 107,3 , ,

Target values 25 4.7E+08 25 4.7E+08 72


C. Piel et al. EPAC 2008

Phase and amplitude stability results

SARAF LLRF:Generator driven resonator (GDR)resonator (GDR) cavity tuning loop

• Above results are for operation of one cavity at a time• Stability measurement period was a few minutes for each cavity


• Stability values are peak-to-peak and are limited by ADC least significant bit Recent commissioning: simultaneous operation of 6 HWRs at ~20 MV/m for several hours

Residual activation from beam loss

A beam loss value of 00 44 nA/mnA/m at 40 MeVA beam loss value of 00..4 4 nA/mnA/m at 40 MeV generates 2 mRem/hr after a 1 year irradiation

30 cm from beam line4 hours after h td

Conditions

shutdownEffects of 40 MeV applied for entire linacAccelerator isAccelerator is operating 365 days per year (~65%)Run deuterons at 40Run deuterons at 40 MeV all the time (25-50%)Accelerator made


entirely of stainless steel (~50% Nb)40 MeV Linac (22 m) Beam line (10 m)

SARAF Phase II simulations with error analysiswith error analysis

Si l i h iSimulations shown in next slides:• 4 mA deuterons at RFQ entrance.entrance. • Last macro-particle=1 nA

B. Bazak et al., Submitted for Publication


Errors are double than in: J. Rodnizki et al. LINAC 2006, M. Pekeler HPSL 2005

J. Rodnizki et al., HB2008

Deuteron beam envelope radius at SARAF SC Linacradius at SARAF SC Linac

200 realizations 70 realizationsSolenoids 19 Tail emphasis simulationsTail emphasis simulations

Bore

rmax

rRM

S

nominal

RFQ exit3.4 mA deuterons

32k/193k particles in core/tailLast macro-particle = 1 nA

S


pGeneral Particle Tracer 2.80 2006, Pulsar Physics S.B. van der Geer, M.J. de Loos http://www.pulsar.nl/

B. Bazak et al., Submitted for PublicationJ. Rodnizki et al., HB2008

Summary and OutlookSARAF Phase I Commissioning status:SARAF Phase I Commissioning status:

Extensive proton beam commissioning through RFQ performedperformedFirst deuteron and H2

+ beams accelerated in RFQOn-going RFQ RF conditioning to enable CW deuteron andOn going RFQ RF conditioning to enable CW deuteron and H2

+ beamsRF commissioning of the PSM to enable beam acceleration through it

Simulations of Phase IIBeam loss criterion for hands-on maintenance is 0.4 nA/m at 40 MeVTail emphasis sim lations indicate beam loss belo 1 nA/m


Tail emphasis simulations indicate beam loss below 1 nA/m

The SARAF CW 40 MeV Proton/Deuteron AcceleratorRFQ voltage squared vs. forward power 250 300 4-Jul...

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