Review of TBL PETS prototype production David Carrillo

Review of TBL PETS prototype production David Carrillo on behalf of Accelerators Group, CIEMAT CLIC 09 WORKSHOP 14/10/2009 1

General layout Fiducials Cooling pipes WR 90 waveguide Copper rods Power extractor Vacuum port Supports D. Carrillo. CLIC 09 WORKSHOP 2

Copper rods � � Each PETS was made of eight OFE copper rods (800 mm) These were the most difficult parts to fabricate: overall tolerance is +/- 0. 02 mm and roughness should be better than 0. 4 micron � The coupling cell is smaller: two different tools were necessary � Two intermediate thermal treatments for stress relaxation Copper rod D. Carrillo. CLIC 09 WORKSHOP 3

Copper rods problems • Problems with temperature control during machining • Internal stresses are higher than those in OF copper (previous prototype) • The copper rods were not measured while screwed to a flat plate D. Carrillo. CLIC 09 WORKSHOP 4

Cooling pipes production D. Carrillo. CLIC 09 WORKSHOP 5

Waveguides brazed in Spanish company AIMEN D. Carrillo. CLIC 09 WORKSHOP 6

Waveguide. Brazing problems in Spain • In the first test, the company used Ag. Cu alloy. Afterwards the company chose the Ni. Au alloy because in case of leaks, reparation is easier and to avoid nickel coating of steel flanges. Risk of leaks due to copper transformation • One waveguide was bent due to deficient packing Solution: to unbend the waveguide as it is soft enough and polish the contact surface to get a good thermal contact and parallelism • Copper parts were cleaned by ultrasonic bath only • The oven at the Spanish company: • has not view port • It has graphite heating elements • The temperature measurement error is unknown D. Carrillo. CLIC 09 WORKSHOP 7

Power extractor. Problems with brazing in Spain D. Carrillo. CLIC 09 WORKSHOP 8

Power extractor. Brazing at CERN Courtesy Serge Mathot, CERN • Copper parts were polished at CERN, because they were not flat enough (machining error in Spain) • Copper parts were cleaned by ultrasonic bath, and at CERN, they were also etched and passivated • Power extractor was successfully brazed at CERN D. Carrillo. CLIC 09 WORKSHOP 9

RF structure assembly D. Carrillo. CLIC 09 WORKSHOP 10

Mechanical measurements on the assembly 113 mm D. Carrillo. CLIC 09 WORKSHOP 11

PETS tank assembly (I) D. Carrillo. CLIC 09 WORKSHOP 12

PETS tank assembly (II) D. Carrillo. CLIC 09 WORKSHOP 13

TBL PETS MEASUREMENTS David Carrillo on behalf of Accelerators Group CIEMAT CLIC 09 WORKSHOP 14/10/2009 14

Single PETS bar measurements: Test device � � A device was designed* to do RF tests of the single PETS bar It consisted of two side blocks put together with a single PETS bar in order to create inside a mode (TE 10) with same phase advance, vg, etc as the decelerating mode E field and probe Phase/period=90º Copper rod Frequency =11. 994 GHz Vg/c=0. 466 � The first 800 mm long bar has been successfully measured with the RF test bench � Measurements strongly depend on electrical contact between device and copper rod and we could observe some deformations in the copper. As 3 D measuring machine were quite repetitive no more copper rod have been tested using this device *Under Igor Syratchev’s supervision D. Carrillo. CLIC 09 WORKSHOP 15

Mode launcher � � � Mode launcher was needed to produce working mode in order to do RF measurements on PETS before final assembly HFSS input coupler model Two mode launchers were manufactured and measured and they were ok for measuring PETS final assembly The two mode launchers were tested together. S 11=-30 d. B S 22=-41 d. B (Min At 11, 989 GHz ) Input couplers manufactured D. Carrillo. CLIC 09 WORKSHOP 16

Power extractor test bench Port 1 Port 2 Coax to WR 90 Input Coupler A b s o r b e r Port 4 Choke Power Extractor A b s o r b e r Coax to WR 90 Input Coupler Port 3 D. Carrillo. CLIC 09 WORKSHOP 17

Power extractor measurements 0 -5 11. 5 12 -10 -15 12. 5 S 11 HFSS Simulation S 11 (d. B) -20 -25 -30 -35 -40 -45 -50 Frequency (GHz) No visible change in S 11 when removing wire, or absorber from port 4 Both S 21 and S 31 are aprox. -3 d. B at 12 GHz D. Carrillo. CLIC 09 WORKSHOP 18

PETS RF measurement bench • A special test bench was designed to measure the assembly of rods • A coaxial antenna was used to measure the field through the slots between the rods D. Carrillo. CLIC 09 WORKSHOP 19

PETS Test bench Port 1 Antenna. Port 5 Coax to WR 90 Input Coupler PETS Port 2 A b s o r b e r Port 4 Choke Power Extractor A b s o r b e r Input Coupler A b s o r b e r Port 3 D. Carrillo. CLIC 09 WORKSHOP 20

S 51 Amplitude (Port 1 -> Antenna) Here the ring used to hold the bars is placed 0. 0 0 100 200 300 400 500 600 700 800 -10. 0 S 51 (d. B) -20. 0 Upper part Lower part -30. 0 -40. 0 -50. 0 -60. 0 Probe position (mm) D. Carrillo. CLIC 09 WORKSHOP 21

PETS phase shift measurements Here the ring used to hold the bars is placed Origin is placed in one of the peaks near power extractor D. Carrillo. CLIC 09 WORKSHOP 22

Dispersion Curve Upper part 12100 12075 12050 12025 12000 11975 Freq (MHz) 11950 11925 Dispersion curve 11900 11875 11850 11825 11800 11775 11750 11725 11700 88. 5 88. 7 88. 9 89. 1 11933 MHz 89. 3 89. 5 89. 7 89. 9 90. 1 90. 3 Phase advance (degrees) 90. 5 90. 7 90. 9 61 MHz detuning D. Carrillo. CLIC 09 WORKSHOP 23

Dispersion Curve In the worst case a 10% power loss Lower part extraction is expected 12100 12075 12050 12025 12000 11975 11950 Freq (MHz) 11925 Dispersion curve 11900 11875 11850 11825 11800 11775 11750 11725 11700 88. 5 88. 7 88. 9 89. 1 11944 MHz 89. 3 89. 5 89. 7 89. 9 90. 1 90. 3 Phase advance (degrees) 90. 5 90. 7 90. 9 50 MHz detuning D. Carrillo. CLIC 09 WORKSHOP 24

Mechanical measurements Before shims After shims D. Carrillo. CLIC 09 WORKSHOP 25

Sensitivity Analysis Distance from PETS cell peak to axis Distance from peak to valley In principle frequency looks quite sensitive to the profile flatness and to the distance from peak to valley Beam axis Inc. Rb Radius of curvature Ra A sensitivity analysis is ongoing to understand the cause of this detuning D. Carrillo. CLIC 09 WORKSHOP 26

TBL Commissioning Status RF power produced Courtesy Steffen Doebert, CERN RF pulse phase Beam current along the line Ø up to 10 A through PETS Ø 20 MW max produced at a pulse length of 280 ns Ø Power production consistent assuming a form factor of 0. 9 ØPETS series production launched together wit CIEMAT(series of 8) D. Carrillo. CLIC 09 WORKSHOP 27

TBL prototype beam line spring 2009 Courtesy Steffen Doebert, CERN BPM, Quad Mover, Quad, PETS-tank D. Carrillo. CLIC 09 WORKSHOP 28

Conclusions & near future work • TBL PETS prototype manufactured, assembled and its RF properties measured • It has been installed in the beam line and is doing ok • We are taking care of the assembly of three more TBL PETS units. Parts production is shared between CERN and CIEMAT • We are going to contribute in the Test Module with the production of 1 double length PETS unit and a hammer choke mode flange D. Carrillo. CLIC 09 WORKSHOP 29