MYRRHA Injector Design

Transcription

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 1

2 Driver Linac Layout 2

3 Injector Part 0.03 MeV 3 C. Zhang, H. Klein, H. Podlech et al., LINAC 2012, THPB005

4 ECR Ion Source Pantechnik Monogan M ma capable 45 kv capable emittance measurement (Allison scanner) included delivery and installation I-2013 ε rms : π mm mrad (requested) Courtesy of D. Vandeplassche 4

5 LEBT Design & Space-Charge Compensation 0.12 T 0.15 T L total =2.3m Courtesy of J.-L. Biarrotte 5

6 LEBT Beam Dynamics Courtesy of J.-L. Biarrotte 6

7 Injector Part 300kW 41kW 47kW =388kW 0.03 MeV 94kW 16kW 20kW =130kW ε= π mm mrad 7 C. Zhang, H. Klein, H. Podlech et al., LINAC 2012, THPB005

8 4-Vane Structure vs. 4-Rod Structure Mini Vanes 8

9 RFQ Rp Values vs. Frequency R p ~ f -1.5 Plot source: MAX_Deliverable_2.1. The value for the IFMIF-EVEDA RFQ was kindly provided by Dr. A. Pisent. 9

10 CH-DTL Shunt Impedance Z eff ~ β -1 10

11 Why change the frequency from 352MHz (EUROTRANS) to 176MHz (MAX)? For all RFQs: the value of Rp=U 2 /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. 11

12 RFQ parameters for EUROTRANS & MAX Parameter EUROTRANS MAX SARAF (H+) f [MHz] I [ma] Win / Wout [MeV] 0,05 / 3 0,03 / 1.5 0,02 / 1.5 U [kv] ,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 ε in t., n., rms [π mm mrad] 0,2 0,2 0,175 ε out t., n., rms [π mm mrad] 0,21 / 0,20 0,22 / 0,22 0,19 / 0,19 ε out l., rms [π kev deg] ,6 36 L [m] 4,3 4 3,8 T [%] ~100 ~100 95,5 T 10mA [%] ~100 ~100 92,3 67 (after Rp [kωm] 61 (MWS) SARAF) 67 (meas.) Pc [kw] 300 (MWS, +20%) Exp.: See Chuan Zhang s talk for more details 12

13 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 Together with A. Bechtold (NTG): New methods for production of stems and electrodes, higher precision (~15 m), 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). 13

14 SARAF RFQ 14

15 E-Field and H-Field simulation with MWS 15

16 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] mm 40 mm 30 mm 16

17 Surface Current Power: 25 kw/m (design) Power Test RFQ: 12 kw Thermal losses: 8 kw (simulated) 17

18 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. 18

19 Electrodes with the new coolingsystem design (NTG) 19

20 Silverplated Tuningplates 20

21 Flow rate [l/sec] Institut für Angewandte Physik Flow rate measurement (stems) 0.35 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, Flow rate [l/sec] Poly. (Flow rate [l/sec]) y = x x Pressure [bar] Reynolds Number

22 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, ,11 156,17 24, ,3 95,52 205,52 0,02 0,01 0,01 181,11 156,16 0, ,3 95,52 205,54 0,04 0,02 0,02 181,13 156,18 0, ,3 95,52 205,55 0,05 0,04 0,03 181,15 156,19 0,02 Expansioncoefficient [mm/ C*m] Lit: 1,6*10-5 1,7*10-5 0,5*10-5 3,0*

23 Thermal measurement Pressure [bar] Coolingwater in [ C] Coolingwater out [ C] Copper Temperature [ C] Thermal bath [ C] 1, ,5 27, , , ,2 24,5 70 6, ,8 70 7,6 18,7 19,65 23,5 70 dm/dt [l/sec]] c [J/(kg*K]] DT [ C] P [W] 0, , , , , , , , , Power losses for a single Stem: 1350 W DT K = 1,05 C (for 7,6 bar) 23

24 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. 24

25 Thermal simulation with cooling (25 kw/m) 25

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33 Injector Part 300kW 41kW 47kW =388kW 0.03 MeV 94kW 16kW 20kW =130kW ε= π mm mrad 33 C. Zhang, H. Klein, H. Podlech et al., LINAC 2012, THPB005

34 CH-DTL parameters for EUROTRANS & MAX EUROTRANS MAX V eff L cell ß avg E a V eff L cell ß avg E a [MV] [m] [MV/m] [MV] [m] [MV/m] RB RT RT RB SC SC SC SC See Holger Podlech s talk for more details 34

35 Transverse Beam Envelopes along the CH-DTL 35 C. Zhang, H. Klein, H. Podlech et al., LINAC 2012, THPB005 See Chuan Zhang s talk for more details

36 CH-1 Institut für Angewandte Physik Room Temperature CH-Cavities Parameter CH-1 CH-2 Unit Frequency MHz Duty factor % Z eff MW/m U eff MV P c kw Prototype cavity presently under construction RF test up to 40 kw/m 36

37 Test Results SC CH-Prototype MYRRHA 37

38 sc CH-Cavities Parameter Unit SC-CH-1 SC-CH-2 SC-CH-3 SC-CH-4 Frequency MHz Gap number Aperture Diam. mm Average b L tot mm E a MV/m U a MV CH3 CH4 CH5 CH6 38

39 325 MHz CH-Cavity Bellow Tuner Static Tuners Helium Vessel Coupler Flanges 39

40 217 MHz CH-Cavity Construction has started Helium vessel Preparation flange Inclined end stem Tuner flange Coupler flange Pickup flange 3D-view of the 217 MHz cavity with helium vessel, without tuners Main parameters of the 217 MHz CH-structure Parameter Unit CH-1 Beta Frequency MHz Gap number 15 Total length mm 687 Cavity diameter mm 409 Cell length mm Aperture mm 20 U a MV Energy gain MeV 2.97 Accelerating gradient MV/ m 5.1 E p / E a 6.4 B p / E a mt/ (MV/m) 5.4 R/ Q Ω 3320 Static tuner 9 Dynamic bellow tuner 3 40