MYRRHA Injector Design - Institut national de physique

Institut für Angewandte Physik

LINAC AG

MYRRHA Accelerator 1st International Design Review, Nov. 12-13, 2012 1

MYRRHA Injector Design

Horst Klein

Dominik Mäder, Holger Podlech, Ulrich Ratzinger,

Alwin Schempp, Rudolf Tiede, Markus Vossberg, Chuan Zhang

Institute for Applied Physics, Goethe-University Frankfurt am Main


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Driver Linac Layout


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Injector Part

C. Zhang, H. Klein, H. Podlech et al., LINAC 2012, THPB005

0.03 MeV


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ECR Ion Source

• Pantechnik Monogan M-1000

• 20 mA capable

• 45 kV capable

• emittance measurement

(Allison scanner) included

• delivery and installation I-2013

εrms: 0.1 - 0.15 π mm mrad

(requested)

Courtesy of D. Vandeplassche


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LEBT Design & Space-Charge Compensation

0.12 T 0.15 T

Ltotal=2.3m

Courtesy of

J.-L. Biarrotte


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LEBT Beam Dynamics

Courtesy of J.-L. Biarrotte


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Injector Part

300kW 41kW 47kW ∑=388kW

94kW 16kW 20kW ∑=130kW

ε=0.2 0.22 0.27π mm mrad


0.03 MeV


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4-Vane Structure vs. 4-Rod Structure

Mini Vanes


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RFQ Rp Values vs. Frequency

Rp~ f -1.5

Plot source: MAX_Deliverable_2.1.

The value for the IFMIF-EVEDA RFQ was kindly provided by Dr. A. Pisent.


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CH-DTL Shunt Impedance

Zeff ~ β -1


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Why change the frequency from 352MHz

(EUROTRANS) to 176MHz (MAX)?

For all RFQs: the value of Rp=U2/P is increasing by a factor of ~2.5.

Nevertheless the best choice for f≥300MHz is the 4-vane RFQ. The

low frequencies allow the use of the simple 4-rod RFQ, which has

some advantages: the chain of /4 resonators are strongly coupled,

resulting in a stable longitudinal field, so for example only 2 plungers

are needed for a 4m long RFQ. The outer conductor plays a small

role, so it can have a lid, which allows a direct access to the

electrodes for mounting and repair, increasing the reliability and

availability. It has a compact size, low weight, is relatively easy to

manufacture at low cost. And it can be built in a rather short time. Its

application allows to reduce the injection energy into the CH-linac to

1.5MeV, which reduces the overall power consumption considerably.


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Parameter EUROTRANS MAX SARAF (H+)

f [MHz] 352 176 176

I [mA] 5 5 5

Win / Wout [MeV] 0,05 / 3 0,03 / 1.5 0,02 / 1.5

U [kV] 65 40 32,5

Es, max / Ek 1,1 1 0,8

amin [mm] 2,3 2,9 2,7

mmax 1,8 2,3 2,7

gmin [mm] 2,6 3,6 3,7

εint., n., rms [π mm‐mrad] 0,2 0,2 0,175

εoutt., n., rms [π mm‐mrad] 0,21 / 0,20 0,22 / 0,22 0,19 / 0,19

εoutl., rms [π keV‐deg] 109 64,6 36

L [m] 4,3 4 3,8

T [%] ~100 ~100 95,5

T10mA [%] ~100 ~100 92,3

Rp [kΩm] 61 (MWS) 67 (after SARAF) 67 (meas.)

Pc [kW] 300 (MWS, +20%) 94 60

RFQ parameters for EUROTRANS & MAX

See Chuan Zhang’s

talk for more details

Exp.: 85% @1mA

65% @4mA


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Several improvements of the RFQ were necessary to

fulfill the MYRRHA requirements (CW operation,

high reliability and availability)

Complete new design of the RFQ structure (e.g. outer conductor,

stems inserted from bottom) by A. Schempp, Lit.: Overview of Recent

RFQ Projects, Proc. LINAC08, MO302, p.41-43. Together with A.

Bechtold (NTG): New methods for production of stems and

electrodes, higher precision (~15m), an improved cooling system,

new techniques for production of cooling channels (milling and

galvanic copper plating, new rf contacts at the tuning plates, better

alignment).


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SARAF RFQ


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E-Field and H-Field simulation with MWS


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RFQ Test Section

Length [mm] 532 (432)

Stem distance [mm] 97

Electrodelength [mm] 342

Beam axis [mm] 145

Frequency [MHz] 176

Quality factor 4900

Tuner (diameter) [mm] 40

45 mm 40 mm 30 mm


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Surface Current

Power: 25 kW/m (design)

Power Test RFQ: 12 kW

Thermal losses: 8 kW

(simulated)


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Stems with the new coolingsystem design (NTG)

Because of the thermal

losses, a very good

water cooling system is

required to hold the

frequency steady during

cw-operation.The new

cooling system of the

stem is split into two

paths. Booth sides of

the stems are well

cooled. In addition the

stems have a channel

for the electrode

cooling.


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Electrodes with the new coolingsystem design (NTG)


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Silverplated Tuningplates


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Flow rate measurement (stems)

y = -0.0025x2 + 0.055x + 0.0344

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 2 4 6 8

Flo

w r

ate

[l/sec]

Pressure [bar]

Flow rate [l/sec]

Poly. (Flow rate [l/sec])

Reynolds Number

4700

8100

11400

16100

18800

19400

20800

Pressure[bar] Flow rate [l/sec] Water speed [m/s]

0,8 0,07 1,04

1,6 0,12 1,73

2,9 0,17 2,48

4,9 0,24 3,45

6,2 0,28 3,96

6,9 0,29 4,20

7,6 0,31 4,40


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Expansion measurement

accuracy 10 m

T [°C] x [mm]} y [mm] z [mm]

T ΔT x1 x2 Δx Δy1 Δy2 z1 z2 Δz

20,7 0 95,54 205,52 109,98 - - 181,11 156,17 24,94

30 9,3 95,52 205,52 0,02 0,01 0,01 181,11 156,16 0,01

40 19,3 95,52 205,54 0,04 0,02 0,02 181,13 156,18 0,01

50 29,3 95,52 205,55 0,05 0,04 0,03 181,15 156,19 0,02 Expansioncoefficient [mm/°C*m]

1,7*10-5 0,5*10-5 3,0*10-5 Lit: 1,6*10-5


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Pressure [bar] Coolingwater in [°C] Coolingwater out [°C] Copper Temperature [°C] Thermal bath [°C]

1,7 19 21,5 27,6 70

3 19 20,65 26 70

5,2 19 20,2 24,5 70

6,5 19 20 23,8 70

7,6 18,7 19,65 23,5 70

Thermal measurement

dm/dt [l/sec]] c [J/(kg*K]] DT [°C] P [W]

0,12 4182 2,5 1261

0,17 4182 1,65 1220

0,25 4182 1,2 1268

0,28 4182 1 1197

0,30 4182 0,95 1223

Power losses for a single Stem: 1350 W

→ DTK = 1,05 °C (for 7,6 bar)


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Thermal measurements on a single stem

Different temperatures during the measurement. The stem was cooled down to nearly

water temperature after 30 seconds with a water flow rate of only 0.08 l/s at a water

pressure of 1 bar.


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Thermal simulation with cooling (25 kW/m)


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Injector Part

300kW 41kW 47kW ∑=388kW

94kW 16kW 20kW ∑=130kW

ε=0.2 0.22 0.27π mm mrad


0.03 MeV


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CH-DTL parameters for EUROTRANS & MAX

EUROTRANS MAX

Veff Lcell ßavg Ea Veff Lcell ßavg Ea

[MV] [m] [MV/m] [MV] [m] [MV/m]

RB1 0.19 0.07 0.08 2.79 0.15 0.10 0.06 1.56

RT1 1.16 0.40 0.09 2.91 1.03 0.54 0.06 1.92

RT2 1.30 0.50 0.10 2.59 1.14 0.66 0.08 1.74

RB2 0.47 0.09 0.10 5.23 0.53 0.36 0.09 1.44

SC1 2.54 0.63 0.11 4.00 3.50 0.86 0.10 4.06

SC2 3.22 0.81 0.14 3.99 3.98 0.99 0.13 4.00

SC3 3.74 0.94 0.16 3.99 4.18 1.07 0.16 3.91

SC4 3.76 1.05 0.18 3.57 4.09 1.07 0.18 3.83

See Holger Podlech’s talk for more details


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Transverse Beam Envelopes along the CH-DTL


See Chuan Zhang’s

talk for more details


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Room Temperature CH-Cavities

Prototype cavity presently under

construction

RF test up to 40 kW/m

Parameter CH-1 CH-2 Unit

Frequency 176 176 MHz

Duty factor 100 100 %

Zeff 113 100 MW/m

Ueff 1.03 1.14 MV

Pc 16.5 18.5 kW

CH-1


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Test Results SC CH-Prototype

MYRRHA


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CH3

CH4 CH5 CH6

sc CH-Cavities Parameter Unit SC-CH-1 SC-CH-2 SC-CH-3 SC-CH-4

Frequency MHz 176.1 176.1 176.1 176.1

Gap number --- 10 9 8 7

Aperture Diam. mm 30 30 40 40

Average b --- 0.102 0.131 0.157 0.178

Ltot mm 916 1060 1129 1127

Ea MV/m 3.88 3.71 3.59 3.47

Ua MV 3.55 3.93 4.05 3.91


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Bellow Tuner Static Tuners

Helium Vessel Coupler Flanges

325 MHz CH-Cavity


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Parameter Unit CH-1

Beta 0.059

Frequency MHz 216.816

Gap number 15

Total length mm 687

Cavity diameter mm 409

Cell length mm 40.82

Aperture mm 20

Ua MV 3.369

Energy gain MeV 2.97

Accelerating gradient MV/ m 5.1

Ep/ Ea 6.4

Bp/ Ea mT/ (MV/m) 5.4

R/ Q Ω 3320

Static tuner 9

Dynamic bellow tuner 3

Main parameters of the 217 MHz CH-structure

Construction has started

3D-view of the 217 MHz cavity with helium vessel, without tuners

Helium vessel

Coupler flange Pickup flange

Inclined

end stem

Tuner flange

Preparation

flange

217 MHz CH-Cavity

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MYRRHA Injector Design - Institut national de physique