TEST OF A 3 GHz HIGH-GRADIENT ACCELERATING CAVITY

TEST OF A 3 GHz HIGH-GRADIENT ACCELERATING CAVITY

U. Amaldi, R. Bonomi, A Degiovanni, M. Garlasché, A. Garonna, I. Mondino, P. Pearce, P.L. Riboni, V. Rizzoglio and S. Verdù Andrès

1CTF3 Committee - UA - 24.3.11

General Concept of a CyclinacGeneral Concept of a Cyclinac

2

The energy can be varied in 2-3 ms in the full range by changing the power pulses sent to the 16-22 accelerating modules (forming 8-11 RF Units)

computer controlled

source

(synchro)cyclotron

gantry

chopped beam at 100-400 Hz

linac Units

fast-cycling beam for tumour multi-painting

RF generators

beams used for other medical

purposes

IBA

CTF3 Committee - UA - 24.3.11

CTF3 Committee - UA - 24.3.11 3

source

General Concept of a CyclinacGeneral Concept of a Cyclinac

LINAC

CyclinacsCyclinacs

4

1993: first Cyclinac proposal

30 MeV cyclotron


5


30 MeV cyclotron CyclinacsCyclinacs


6

2003: test of LIBO-62 MeV (M. Weiss - TERA-CERN-INFN)


30 MeV cyclotron CyclinacsCyclinacs




30 MeV cyclotron

2007: first CABOTO design

CyclinacsCyclinacs

7

8



30 MeV cyclotron


2008: Pediatric IDRA for Biella

CyclinacsCyclinacs

9



30 MeV cyclotron


2010: First Unit of LIGHT ADAM=Application of Detectors

and Accelerators to Medicine


CyclinacsCyclinacs

10



30 MeV cyclotron


2009: First Unit of LIGHT ADAM=Application of Detectors

and Accelerators to Medicine


CyclinacsCyclinacs

2010TULIP +

CABOTO


400MeV/u

CABOTO – C =

CArbon BOoster for Therapy in Oncology

150MeV/u

CABOTO-C components

Source EBIS - SC

Cyclotron K 600 - SC210 tons

Linac CCL @ 5.7 GHz14 modules

RF power system

14 Klystrons (Ppeak = 12 MW)

150-400 MeV/u

The last design of a cyclinac for carbon ions: The last design of a cyclinac for carbon ions: CABOTO-CCABOTO-C

Dimensional comparison among carbon ion accelerators


TULIP = TUrning LInac for Proton therapy35 MeV cyclotron

3 or 5.7 GHz linac


Proton trajectory

15-20 MV/m

14

62 MeV

74 MeV

4 MW at 3 GHz

LIBO

LIBO and LIGHT at 3 GHz: gradient E ≤ 20 MV/m

Surface field Es ≤ 90 MV/m(Kilpatrick ≤ 2)

SW Cell Coupled Linac for SW Cell Coupled Linac for ββ = 0.25-0.60= 0.25-0.60


Proton trajectory

15-20 MV/m

15

62 MeV

74 MeV

4 MW at 3 GHz

LIBO




For CABOTO and TULIP:E ≤ 35-40 MV/m

At 3 GHz or higher


Proton trajectory

15-20 MV/m

16

62 MeV

74 MeV

4 MW at 3 GHz

LIBO





At 3 GHz or higher


Es / E ≤ 4.5 - 5

Problem: ‘the Nose’

Proton trajectory

15-20 MV/m

17

62 MeV

74 MeV

4 MW at 3 GHz

LIBO





At 3 GHz or higherEs / E ≤ 4.5 - 5

‘Nose’

As far as Es is concerned:

TERA’s 40 MV/mare equivalent to CLIC’s 100 MV/m

Problem: ‘the Nose’

Proton trajectory

15-20 MV/m

18

62 MeV

74 MeV

4 MW at 3 GHz

LIBO






BDR for TERA:Linac is 15 m long and a treatment is (20x100 Hz x120s) pulses

BDR ≤ 3 10-7 CTF3 Committee - UA - 24.3.11Problem: ‘the Nose’

Proton trajectory

15-20 MV/m

19

62 MeV

74 MeV

4 MW at 3 GHz

LIBO






TERA is facing the same challenges as CLIC BUT

cannot go to freguencies larger than 6 GHz:

tranverse acceptance,distributed sources

CTF3 Committee - UA - 24.3.11Problem: ‘the Nose’

Since 2009 TERA has started an high gradient Since 2009 TERA has started an high gradient test Programtest Program

Prototype test structures:3 GHz single-cell cavity5.7 GHz single-cell cavitymulti-cell structure


3 GHz Test Cavity general layout3 GHz Test Cavity general layout• Single accelerating cell

• H-coupled to WR284 waveguide

• Cooling system (two plates, in-out pipes)


Preliminary high power testPreliminary high power test

High Power Test (@CTF3 – Feb 2010)

Preliminary results compared with literature data[A. Grudiev et al, Phys. Rev. ST Accel. Beam 12 (2009)]

Indirect measurments of field through Faraday Cup

BD event

S. Verdú Andrés et al. (2010) LINAC10 Proceedings

3 µs1 µs

Low Power Measurments (Jan 2010)

short position



High power test: first results after few nights and no conditioning

x = 30 (other expriments)x= 6 TERA @ 3 GHz

acceptable range

150 – 170 MV/m

Microscopy surface InspectionMicroscopy surface Inspection

Microscope’s inside view on nose region: several craters and sparse activity can be observed.

Difficulties in reconstructing the actual position of the craters.

Final conclusion will come after cutting and opening the cavity.


To complete the measurementTo complete the measurement


we request 4 weeks

for mounting, conditioning and testing

this cavity

The pieces of the 5.7 GHz test cavity are inhouse The pieces of the 5.7 GHz test cavity are inhouse


Low power tuning in 10 daysTo be tested after the 3 Ghz cavity in Frascati (L. Picardi)

(with ADAM’s magnetron)

Prototype # 1 & 2 3 tendering

Material C10100 Copper

Dimensional tolerance band 10 μm 5 μm

Surface roughness (Ra) 0.4 μm 0.025 μm

TEST OF A 3 GHz HIGH-GRADIENT ACCELERATING CAVITY

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