status of the high current proton accelerator for the ... · (352 mhz) microwave rf source high...

Status of the High Current Proton Accelerator for the TRASCO Program

Paolo PieriniINFN Milano - LASA

on behalf of the TRASCO_ACC group

EPAC 2002 Paris, 3-7 June 2002

TRASCO_ACCD. Barnia, G. Bellomoa, G. Bisoffib, A. Bosottia, L. Celonac, A. Chincarinid, G. Ciavolac, M. Comunianb, A. Faccob, S. Gamminoc, G. Gemmed, G. Lamannae, A. Lombardib, P. Michelatoa, M. Napolitanof, C. Pagania, A. Palmierib, R. Parodid, P. Pierinia, A. Pisentb, F. Scarpab, D. Sertorea, V. Zviagintsevb,

aINFN Milano LASA http://wwwlasa.infn.itbINFN-LNL http://www.lnl.infn.itcINFN-LNS http://www.lns.infn.itdINFN Genova http://www.ge.infn.it eINFN Bari http://www.ba.infn.itfUniversity and INFN, Napoli http://www.na.infn.it

P. Pierini EPAC 2002, Paris, 3-7 June 2002 2

The TRASCO Program

TRASCO: conceptual study and the prototyping of components for an accelerator driven system for nuclear waste transmutation, and involves research agencies and Italian companies

TRASCO/ACC Accelerator studies: lead by INFN

TRASCO/SS Subcritical reactor studies: lead by ENEA

TRASCO/ACC (1998-2004, in three funding stages) is devoted to: Conceptual design of a high current superconducting proton linac

I=30 mA, E = 1 GeV Construction and R&D activities on key items:

an 80 kV, 35 mA proton source (INFN - LNS) a 5 MeV, 30 mA, CW RFQ (INFN - LNL) SC cavity prototypes for low β cavities (


Beam Dynamics

The Reference Linac Design

3 section linac: 85/100 - 200 MeV, β=0.47 200 - 500 MeV, β=0.65 500 1000/2000 MeV, β=0.85

Five(six) cell elliptical cavitiesQuadrupole doublet focussing: multi-cavity cryostats between doublets

704.4 MHz

5 - 85/100 MeV SC linac

Baseline design:Reentrant cavities (352 MHz)

Alternative design:Spoke, λ/2, λ/4, ladder

8βλ FODO focussing with sc magnets

High transm

ission 95%30 m

A, 5 M

eV(352 M

Hz)

Microwave

RF SourceH

igh current (35m

A)

80keV

High Energy SC LinacISCLRFQSource

Proton Source RFQ Medium energy ISCL linac 3 sections high energy SC linac

80 keV 5 MeV ~100 MeV 200 MeV 500 MeV >1000 MeV


TRIPS: TRASCO Intense Proton Source

High intensity (tens mA) proton sources exist Chalk River, Los Alamos, CEA-Saclay

ADS asks for high reliability and availabilityAdditional efforts are required for:

Voltage and current stability Control of the low beam emittance

Design in 1999, source in LNS in May 2000Achievements:

First beam of 20 mA @ 60 kV in Jan 2001 80 kV, 55 mA operation in Aug 2001

Off-resonance microwave discharge source (2.45 GHz), based on SILHI (CEA/Saclay)

80 kV

To be measured

55 mA (~90% p.f.)

Achieved

80 kVOperating voltage

0.2 π mm mradBeam emittance

35 mAProton Beam current

TRIPS Goals:

Reported at EPAC2000, PAC2001


2 kW RF generator

Plasma chamber

Layout of the Source and LEBT

Extraction electrodes

Studies on SILHI extraction system lead to: Pentode

configuration with new geometry

Lowered voltage: from 95 kV to 80 kV


2 kW RF generator

Plasma chamber

Layout of the Source and LEBT

Extraction electrodes

Studies on SILHI extraction system lead to: Pentode

configuration with new geometry

Lowered voltage: from 95 kV to 80 kV

Matching transformer (impedance match)

Moving coils to adjust ECR region

4-step binomial transformer for waveguide to plasma impedance matching


Performances and recent development

A rms emittance below 0.2 π mm mrad has been calculated with beam dynamics simulations, crosschecking different codes

Emittance unit from CEA is being shipped to Catania for measurementsLEBT for beam analysis and characterization:

Solenoid (focussing) Beam alignment monitor 2 current transformers for beam current measurements 10 kW beam stop

Reliability tests have been performed: at 65 kV/15 mA: 24 h with no beam

interruptions Tests at 80 kV are underway (improving)

A new control system for automatic restart procedures after discharge is being implemented

10 kW beam stop

LEBT line


Low Energy Linac

The low energy linac is split in two components: A normal conducting CW Radio Frequency Quadrupole (RFQ): from 80 keV

to 5 MeV RFQ design: 3 resonantly coupled segments. Modulation:

Radial match in the structure Shaper Gentle buncher (from dc to 352.2 MHz bunches) Accelerator (boosts up to 5 MeV, longest portion)

A superconducting linac (ISCL): from 5 MeV to 100 MeV Reentrant cavities for highest availability (allowing beam on with 1 cavity off) λ/4, λ/2 cavities Spoke cavities

Papers contributed to this Conference (TU and TH)Papers contributed to this Conference (TU and TH)

coupling cells

wave guide RF loop

7.13 mtechn. model

tuners wave guide vacuum ports RF loop


RFQ Design

Different optimization procedure for TRASCO RFQ w.r.t. LEDA Limit to 1 RF source (1.3 MW CERN-LEP klystron) Lower design current of 30 mA (transmission of 96%) Peak surface electric field is 33 MV/m, 1.8 Kilpatrick limit Simplified engineering/manufacturing choices

Substantial heat dissipation in the structure ~ 600 kW totalThree resonantly coupled segments

1.8 KilpatrickPeak Field

600 kW (structure)

150 kW (beam)RF Power

7.13 m (3 sections)Length

0.2 π mm mrad TBeam emittance

5 MeVFinal Energy

0.18 π deg MeV L

30 mA (96 % transmission)Beam current

TRASCO RFQ:

Poster THPLE083: Field tuning of the TRASCO RFQ



RFQ Design

Different optimization procedure for TRASCO RFQ w.r.t. LEDA Limit to 1 RF source (1.3 MW CERN-LEP klystron) Lower design current of 30 mA (transmission of 96%) Peak surface electric field is 33 MV/m, 1.8 Kilpatrick limit Simplified engineering/manufacturing choices

Substantial heat dissipation in the structure ~ 600 kW totalThree resonantly coupled segments

1.8 KilpatrickPeak Field

600 kW (structure)

150 kW (beam)RF Power

7.13 m (3 sections)Length

0.2 π mm mrad TBeam emittance

5 MeVFinal Energy

0.18 π deg MeV L

30 mA (96 % transmission)Beam current

TRASCO RFQ:



Copper dominated Not space charge limited Not beam loading limited 150 kW to beam 600 kW to copper


RFQ: fabrication tests

A 3 m Al model of the structure has been built and measured at LNL, and achieved the necessary field stabilizationA 220 mm part of the structure has been built to test the full fabrication procedures

Brazing Water channels by long (1 m) drilling

Full structure is under fabrication


Superconducting low energy linac

Single or two-gap structure linac Moderate energy gain/cavity Solid state RF amplifiers 8 βλ focussing lattice

Various options, are being considered Reentrant cavities Spoke cavities λ/4 cavities ladderQuarter Wave resonator (QWR) 2 gap structure of the ALPI linac in INFN-LNL

Reentrant cavity single gap structure. He Vessel integrated in the cavity2 gap spoke cavity

Poster THPDO022: RF testing of the TRASCO SC Reentrant Cavity for High Intensity Proton Beams

Poster THPDO022: RF testing of the TRASCO SC Reentrant Cavity for High Intensity Proton Beams

Poster TUPLE121: A 2.5 kW, Low Cost 352 MHz Solid State RF Amplifier for CW and Pulsed Operation

Poster TUPLE121: A 2.5 kW, Low Cost 352 MHz Solid State RF Amplifier for CW and Pulsed Operation

4βλ

tuning

F D

4βλ


The high energy linac

Designed with high current beam dynamics criteria to avoid emittance growth (smooth, tune resonances, ...)

655# cells/cavity

1 GeV480 MeV190 MeV

12.3 MV/m10.2 MV/m8.5 MV/mMax. Eacc (MV/m)

484824# cavities in section

12

8.5 m

480 MeV

102 m

0.85

16

5.8 m

190 MeV

93 m

0.65

12# periods

4.2 mDoublet period

100 MeVInitial/Final Energy

0.47Section β

50 mLength

Conceptual design of the 3 section linacDevelopment and test of prototype cavities

At 352 MHz with the LEP II sputtering technology At 704 MHz, bulk niobium, for the lowest β

Design and engineering of cavity components and ancillaries Cryomodule, tuner system, piezo damping,

RF Test infrastructure

Papers contributed to this Conference (WE and TH)Papers contributed to this Conference (WE and TH)

Clean room and HPR

UPurewater

RF Test Bunker


Conceptual design: cavity design

Parametric tool for the analysis of the cavity shape on the electromagnetic (and mechanical) parametersInner cell tuning is performed through the diameter, all the characteristic cell parameters stay constant: R, r, α, d, L, RirisEnd cell tuning is performed through the wall angle inclination, α,or distance, d. R, L and Riris are set independentlyEnd groups for a 4 die cavity can be tuned using the end cell diameter (and a,d,R,L, Riris are set independently)

βg = 0.81 Cavity for SNS 4 dies

Ep/Eacc 2.19 (2.14 inner cell)Bp/Eacc [mT/(MV/m)] 4.79 (4.58 inner cell)R/Q [Ω] 485G [Ω] 233k [%] 1.52QBCS @ 2 K [109] 36.2Frequency [MHz] 805.00Field Flatness [%] 1.1

KL70 = -0.7 [Hz/(MV/m)2] KL80 = -0.8 [Hz/(MV/m)2]

Nb thickness = 3.8 mm

Effective β that matches the TTF curve = 0.830

Geometrical ParametersInner cell End Cell Left End Group (coupler)

Left RightL [mm] 75.5 75.5 75.5Riris [mm] 48.8 48.8 48.8 70.0D [mm] 164.15 164.15 166.11d [mm] 15.0 13.0 15.0 13.0r 1.8 1.6 1.8 1.6R 1.0 1.0 1.0α [deg] 7.0 10.072 7.0 10.0

Tool used also for the SNS cavity design

Longitudinal eigenmode analysis


Conceptual design: linac design

Build linac from simple rules, with control of longitudinal & transverse phase advances

10.0 mm X 3.000 mrad

A= -2.479 B= 8.6115 HA= -0.467 B= 3.0957 V

10.0 Deg X 1000.0 KeV

A= 0.001 B= 0.0476 Z

10.0 mm X 3.000 mrad

10.0 Deg X 1000.0 KeV

10.0 mm 10. Deg Length= 506397.mmVert

Horiz, Long

1

Q

2 3

Q

4 5

TNK

6 7

TNK

8 9

Q

10 11

Q

12 13

TNK

14 15

TNK

16 17

Q

18 19

Q

20 21

TNK

22 23

TNK

24 25

Q

26 27

Q

28 29

TNK

30 31

TNK

32 33

Q

34 35

Q

36 37

TNK

38 39

TNK

40 41

Q

42 43

Q

44 45

TNK

46 47

TNK

48 49

Q

50 51

Q

52 53

TNK

54 55

TNK

56 57

Q

58 59

Q

60 61

TNK

62 63

TNK

64 65

Q

66 67

Q

68 69

TNK

70 71

TNK

72 73

Q

74 75

Q

76 77

TNK

78 79

TNK

80 81

Q

82 83

Q

84 85

TNK

86 87

TNK

88 89

Q

90 91

Q

92 93

TNK

94 95

TNK

96 97

Q

98 99

Q

100101

TNK

102103

TNK

104105

Q

106107

Q

108109

TNK

110111

TNK

112113

Q

114115

Q

116117

TNK

118119

TNK

120121

Q

122123

Q

124125

TNK

126127

TNK

128129

Q

130131

Q

132133

TNK

134135

TNK

136137

Q

138139

Q

140141

TNK

142143

TNK

144145

Q

146147

Q

148149

TNK

150151

TNK

152153

Q

154155

Q

156157

TNK

158159

TNK

160161

Q

162163

Q

164165

TNK

166167

TNK

168169

Q

170171

Q

172173

TNK

174175

TNK

176177

Q

178179

Q

180181

TNK

182183

TNK

184185

Q

186187

Q

188189

TNK

190191

TNK

192193

Q

194195

Q

196197

TNK

198199

TNK

200201

Q

202203

Q

204205

TNK

206207

TNK

208209

Q

210211

Q

212213

TNK

214215

TNK

216217

Q

218219

Q

220221

TNK

222223

TNK

224225

Q

226227

Q

228229

TNK

230231

TNK

232233

Q

234235

Q

236237

TNK

238239

TNK

240241

Q

242243

Q

244245

TNK

246247

TNK

248249

Q

250251

Q

252253

TNK

254255

TNK

256257

Q

258259

Q

260261

TNK

262263

TNK

264265

Q

266267

Q

268269

TNK

270271

TNK

272273

Q

274275

Q

276277

TNK

278279

TNK

280281

Q

282283

Q

284285

TNK

286287

TNK

288289

Q

290291

Q

292293

TNK

294295

TNK

296297

Q

298299

Q

300301

TNK

302303

TNK

304305

Q

306307

Q

308309

TNK

310311

TNK

312313

Q

314315

Q

316317

TNK

318319

TNK

320321

Q

322323

Q

324325

TNK

326327

TNK

328329

Q

330331

Q

332333

TNK

334335

TNK

336337

Q

338339

Q

340341

TNK

342343

TNK

344345

Q

346347

Q

348349

TNK

350351

TNK

352353

Q

354355

Q

356357

TNK

358359

TNK

360361

Q

362363

Q

364365

TNK

366367

TNK

368369

Q

370371

Q

372373

TNK

374375

TNK

376377

Q

378379

Q

380381

TNK

382383

TNK

384385

TNK

386387

TNK

388389

Q

390391

Q

392393

TNK

394395

TNK

396397

TNK

398399

TNK

400401

Q

402403

Q

404405

TNK

406407

TNK

408409

TNK

410411

TNK

412413

Q

414415

Q

416417

TNK

418419

TNK

420421

TNK

422423

TNK

424425

Q

426427

Q

428429

TNK

430431

TNK

432433

TNK

434435

TNK

436437

Q

438439

Q

440441

TNK

442443

TNK

444445

TNK

446447

TNK

448449

Q

450451

Q

452453

TNK

454455

TNK

456457

TNK

458459

TNK

460461

Q

462463

Q

464465

TNK

466467

TNK

468469

TNK

470471

TNK

472473

Q

474475

Q

476477

TNK

478479

TNK

480481

TNK

482483

TNK

484485

Q

486487

Q

488489

TNK

490491

TNK

492493

TNK

494495

TNK

496497

Q

498499

Q

500501

TNK

502503

TNK

504505

TNK

506507

TNK

508509

Q

510511

Q

512513

TNK

514515

TNK

516517

TNK

518519

TNK

520521

Q

522523

Q

524525

TNK

526527

TNK

528529

TNK

530531

TNK

532533

Q

534535

Q

536537

TNK

538539

TNK

540541

TNK

542543

TNK

544545

Q

546547

Q

548549

TNK

550551

TNK

552553

TNK

554555

TNK

556557

Q

558559

Q

560561

TNK

562563

TNK

564565

TNK

566567

TNK

568569

Q

570571

Q

572573

TNK

574575

TNK

576577

TNK

578579

TNK

580581

Q

582583

Q

584585

TNK

586587

TNK

588589

TNK

590591

TNK

592593

Q

594595

Q

596597

TNK

598599

TNK

600601

TNK

602603

TNK

604605

Q

606607

Q

608609

TNK

610611

TNK

612613

TNK

614615

TNK

616617

Q

618619

Q

620621

TNK

622623

TNK

624625

TNK

626627

TNK

628629

Q

630631

Q

632633

TNK

634635

TNK

636637

TNK

638639

TNK

640641

Q

642643

Q

644645

TNK

646647

TNK

648649

TNK

650651

TNK

652653

Q

654655

Q

656657

TNK

658659

TNK

660661

TNK

662663

TNK

664665

Q

666667

Q

668669

TNK

670671

TNK

672673

TNK

674675

TNK

676677

Q

678679

Q

680681

TNK

682683

TNK

684685

TNK

686687

TNK

688689

Q

690691

Q

692693

TNK

694695

TNK

696697

TNK

698699

TNK

700701

Q

702703

Q

704705

TNK

706707

TNK

708709

TNK

710711

TNK

712713

Q

714715

Q

716717

TNK

718719

TNK

720721

TNK

722723

TNK

724725

Q

726727

Q

728729

TNK

730731

TNK

732733

TNK

734735

TNK

736737

Q

738739

Q

740741

TNK

742743

TNK

744745

TNK

746747

TNK

748749

Q

750751

Q

752753

TNK

754755

TNK

756757

TNK

758759

TNK

760761

Q

762763

Q

764765

TNK

766767

TNK

768769

TNK

770771

TNK

772773

Q

774775

Q

776777

TNK

778779

TNK

780781

TNK

782783

TNK

784785

Q

786787

Q

788789

TNK

790791

TNK

792793

TNK

794795

TNK

796

A= -0.957 B= 15.5345 HA= -0.210 B= 10.0358 V

A= -0.122 B= 0.0015 Z

I= 40.00 mAW = 87.000 2007.422 MeVFREQ= 704.40 MHz WL= 425.60 mmEMITI= 4.221 4.221 1000.00EMITO= 0.625 0.625 1000.00

PRINTOUT VALUES NP NE VALUE 1 1 8.2720 1 6 468.0000 2 6 0.0000 3 6 0.0000

MATCHING TYPE = 9DESIRED VALUES (BEAMF) alpha betax -2.0553 15.4239y -0.7381 7.3608z -0.0259 0.0060

MATCH VARIABLES (NC=6) MP ME VALUE 3 373 -31.6848 3 381 -16.8251 1 369 14.2740 1 371 -14.1363 1 377 15.0778 1 379 -14.6226

CODE: TRACE3D vMI1FILE: G:\dynrash\224\cav\cav-quad.t3dDATE: 22/12/1999TIME: 17:56:59

Find matched beam solution in all linac

Poster WEPLE109: Adiabatic Matching in Periodic Accelerating Lattices for Superconducting Proton Linacs

Poster WEPLE109: Adiabatic Matching in Periodic Accelerating Lattices for Superconducting Proton Linacs

Run non-linear multi-particle simulations for confirmation of design


352 MHz cavities with CERN (MOU) Use LEP II sputtering technology Single cell and 5 cell sputtered β = 0.85 Cavity integrated in a LEP type cryostatAll tests reached the design goals, indeed performed as the best LEP batchBut: Bulk niobium is needed at lower β, and the gradient is moderate w.r.t 704 MHz

352 MHz β=0.85 prototypes with CERN

Test in a modified LEPII cryomodule (Aug. 2001)

Powered to 250 kW 7 MV/m


0 20 40 60 80 100 120 140109

1010

1011

Quench No quench Quench

design value, Bp=50 mT

Ep=30.3 MV/m,

Eacc

=8.5 MV/m

Q0

Bp [mT], E

p [MV/m], E

acc [MV/m]

Z101 RRR=30 Z102 RRR=30 Z103 RRR=250 Z104 RRR=250

0 10 20 30 40 50 60 70

0 2 4 6 8 10 12 14 16 18 20 22

Poster THPDO023: RF Tests of the Single Cell Prototypes for the TRASCO β=0.47 Cavities

Poster THPDO023: RF Tests of the Single Cell Prototypes for the TRASCO β=0.47 Cavities

β=0.47 single cell cavities prototypes

For 1-cell:Ep/Eacc = 2.90Bp/Eacc = 5.38 mT/(MV/m)

For 5-cell:Ep/Eacc = 3.57Bp/Eacc = 5.88 mT/(MV/m)

Max Epeak = 74 MV/mMax Bpeak = 138 mT

Fabricated with RRR>30 & RRR>250 Niobium at ZanonBCP, HPR and tests at TJNAF (Z104) and Saclay (Z101-Z103)

Two 5 cell cavities are under fabrication

BpEpEacc


Baseline of the smooth linac design

Continuous phase advances at transitions

RFQ


Full SC linac from 5 MeV to 1 GeV

Results of non-linear simulationsNo particle losses, beams well confined

x rms envelope

y rms envelope

Phase rms envelope

Input @ 5 MeV 105 ptcl

Output @ 1 GeV


Rms emittances growth (from end of RFQ to full energy) < 2%

Avoided: Structure resonances Tune resonances Big tune depression

Guaranteed: Smooth beamline changes Good matching procedures


The effort to build a complete ADS system exceeds the capabilities (and the funding availability) of any national program like TRASCO

TRASCO means to provide significant R&D and prototipical effort along the road to the design of a transmuter system

cfr. A European Roadmap for Developing Accelerator Driven Systems (ADS) for Nuclear Waste Incineration, by the European Technical Working Group on ADS, April 2001 (available in http://itumagill.fzk.de/ADS/)

Already in the FP5 of the European Commission a Program has beenfunded: PDS-XADS Preliminary Design Studies for an eXperimental Accelerator Driven System

25 Partners, from Research Institutions to EU Industries 12 M Program (50% supported by the Commission) Several Working Packages, dealing with various aspects of an ADS WP3 is dedicated to the Accelerator

More to come in the FP6

Perspectives

status of the high current proton accelerator for the ... · (352 mhz) microwave rf source high...

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