review of tbl pets prototype production

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Review of TBL PETS prototype production

David Carrillo on behalf of Accelerators Group, CIEMAT

CLIC09 WORKSHOP 14/10/2009

D. Carrillo. CLIC09 WORKSHOP

2

General layout

Copper rods

Power extractor Vacuum port

WR90 waveguide

Supports

Fiducials

Coolingpipes


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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


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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

-400 -200 0 200 400-0.1

-0.05

0

0.05

0.1

Longitudinal postion (mm)

Err

or (m

m)

-400 -200 0 200 400-0.1

0

0.1

0.2

0.3

Longitudinal position (mm)

Z er

ror (

mm

)


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Cooling pipes production


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Waveguides

Waveguides brazed in Spanish company AIMEN


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Waveguide. Brazing problems in Spain

•In the first test, the company used AgCu alloy. Afterwards the company chose the NiAu 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


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Power extractor. Problems with brazing in Spain


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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


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RF structure assembly


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Mechanical measurements on the assembly

ROD 1-5 ROD 4-8 ROD 7-3 ROD 6-2R L R L R L R L AVERAGE

DOWN 113.045 113.035 112.950 112.990 113.045 113.010 112.950 112.950 112.997MID-DOWN 113.040 113.040 112.960 112.980 112.930 112.925 112.955 112.960 112.974BELOW RING 113.055 113.040 113.045 113.055 113.035 113.010 113.045 113.035 113.040ABOVE RING 113.040 113.020 113.045 113.060 113.070 113.050 113.065 113.055 113.051MID-UP 112.965 112.980 112.990 112.995 112.980 112.985 113.035 113.020 112.994UP 112.990 113.010 113.040 113.050 112.970 112.940 113.080 113.060 113.018

AVERAGE 113.023 113.021 113.005 113.022 113.005 112.987 113.022 113.013 113.012

113mm

113mm


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PETS tank assembly (I)


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PETS tank assembly (II)

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TBL PETS MEASUREMENTS

David Carrillo on behalf of Accelerators Group CIEMAT

CLIC09 WORKSHOP 14/10/2009


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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 (TE10) with same phase advance, vg, etc as the decelerating mode

Single PETS bar measurements:Test device

Phase/period=90ºFrequency =11.994 GHzVg/c=0.466

E field and probe

Copper rod

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 3D measuring machine were quite repetitive no more copper rod have been tested using this device

*Under Igor Syratchev’s supervision


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Mode launcher was needed to produce working mode in order to do RF measurements on PETS before final assembly

Two mode launchers were manufactured and measured and they were ok for measuring PETS final assembly

The two mode launchers were tested together. S11=-30dB S22=-41 dB (Min At 11,989GHz )

Mode launcher

Input couplers manufactured

HFSS input coupler model


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Power extractor test bench

InputCoupler

InputCoupler

Coax to

WR90

Power Extractor

Absorber

Absorber

Port1Port4Port2

Port3

Choke

Absorber

Coax to

WR90


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Power extractor measurements

No visible change in S11 when removing wire, or absorber from port 4

Both S21 and S31 are aprox. -3dB at 12 GHz

11.5 11.6 11.7 11.8 11.9 12 12.1 12.2 12.3 12.4 12.5

-50-45-40-35-30-25-20-15-10-50

Frequency (GHz)

S11

(dB)

S11 HFSS Simulation


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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


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PETS Test bench

Port3

InputCoupler

Coax to

WR90

Power Extractor

Absorber

Absorber

Port1

Port4Port2

Choke

Absorber

InputCouplerPETS

Antenna. Port 5


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S51 Amplitude (Port1 -> Antenna)

0 100 200 300 400 500 600 700 800

-60.0

-50.0

-40.0

-30.0

-20.0

-10.0

0.0

Probe position (mm)

S51

(dB)

Upper partLower part

Here the ring used to hold the bars is placed


PETS phase shift measurements

Origin is placed in one of the peaks near power extractor

Here the ring used to hold the bars is placed

22


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Dispersion CurveUpper part

88.5 88.7 88.9 89.1 89.3 89.5 89.7 89.9 90.1 90.3 90.5 90.7 90.911700

11725

11750

11775

11800

11825

11850

11875

11900

11925

11950

11975

12000

12025

12050

12075

12100

Dispersion curveLinear (Dispersion curve)

Phase advance (degrees)

Freq

(MHz

)

11933 MHz 61 MHz detuning


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Dispersion CurveLower part

88.5 88.7 88.9 89.1 89.3 89.5 89.7 89.9 90.1 90.3 90.5 90.7 90.911700

11725

11750

11775

11800

11825

11850

11875

11900

11925

11950

11975

12000

12025

12050

12075

12100

Dispersion curveLinear (Dis-persion curve)

Phase advance (degrees)

Freq

(MHz

)

11944 MHz 50 MHz detuning

In the worst case a 10% power loss extraction is expected


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Mechanical measurements

ROD 1-5 ROD 4-8 ROD 7-3 ROD 6-2 AVERAGER L R L R L R L


AVERAGE 113.006 112.999 112.997 112.968 112.960 112.978 112.985 112.994 112.986

ROD 1-5 ROD 4-8 ROD 7-3 ROD 6-2R L R L R L R L AVERAGE


AVERAGE 113.023 113.021 113.005 113.022 113.005 112.987 113.022 113.013 113.012

After shims

Before shims


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Sensitivity Analysism

MHzdRadf

2.0

mMHz

dIncRbdf

1.1

Distance from PETS cell peak to axis

Radius of curvature

deg2MHz

edRcurvaturdf

Distance from peak to valley

R curvature

Beam axis

Ra

IncRb

A sensitivity analysis is ongoing to understand the cause of this detuning

In principle frequency looks quite sensitive to the profile flatness and to the distance from peak to valley


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0 50 100 150 200 250 300 350 400 450 500-100

-80

-60

-40

-20

0

20

40

60

80

100

Time (ns)

RF

phas

es (d

eg)

Pout leftPout right

0 100 200 300 400 500 600-16

-14

-12

-10

-8

-6

-4

-2

0

2

Time (ns)

Bea

m c

urre

nt (A

)

BPM0150BPS0210BPS0250BPS0310BPM0310

-100 0 100 200 300 400 500-1

0

1

2

3

4

5

6

7

8

9

Time (ns)

RF

pow

er (M

W)

Pout leftPout rightPref leftPref rightP predict

TBL Commissioning StatusRF power produced RF pulse phase

Beam current along the line

Courtesy Steffen Doebert, CERN

up to 10 A through PETS 20 MW max produced at a pulse length of 280 ns Power production consistent assuming a form factor of 0.9PETS series production launched together wit CIEMAT(series of 8)


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TBL prototype beam line spring 2009

BPM, Quad Mover, Quad, PETS-tank

Courtesy Steffen Doebert, CERN


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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

review of tbl pets prototype production

Documents

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copper transformation

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