Analysis of the Energy Gain Measurements in TBTS

Oleksiy Kononenko23/Mar/2011

2

Motivation

PRELIMINARY

Javier Barranco

New calibration + effective power increase

3

Energy Gain Measurements in TBTSAnalyzed acceleration measurements (events) in TBTS including the corresponding timestamps are gathered by Javier Barranco Garcia here:

• http://elogbook.cern.ch/eLogbook/eLogbook.jsp?shiftId=1032364• http://elogbook.cern.ch/eLogbook/eLogbook.jsp?shiftId=1032385• http://elogbook.cern.ch/eLogbook/eLogbook.jsp?shiftId=1032677

Temperature, C Total Number of Events37 1750 655 560 11

4

One quarter of the TD24_tank (12WDSDVG1.8T) AS installed in TBTS

5

Results of the S-parameters HFSS Simulation

11.85 11.9 11.95 12 12.05

-40

-35

-30

-25

-20

-15

-10

-5

0

Frequency, GHz

dB

S11

S12

6

Accelerating Voltage in TD24(Pin = 4W)

11.96 11.97 11.98 11.99 12 12.01 12.02 12.03 12.040

1000

2000

3000

4000

5000

6000

7000

Frequency,GHz

Vo

lta

ge

, V

abs(V+)

11.994 GHz

7

Layout of the Instrumentation for the CTF3 Two-beam Test-stand

Important input from Alexey Dubrovskiy: to use PPI0431 signal instead of the PSI0631 one and then take into account recirculation in PETS and waveguide network between PETS and AS. In this way more reliable input pulse is obtained for AS.

8

90 MW Pulse in CTF3 vs CLIC nominal (100 MV/m unloaded) pulse

0 50 100 150 200 250 300 3500

10

20

30

40

50

60

70

80

90

Time, ns

Po

we

r, M

W /

Ph

as

e,

de

g

CTF3,

CTF3, |P|CLIC nominal

9

Simulation of the Transmission

0 50 100 150 200 2500

5

10

15

20

25

30

35

Time, ns

Po

we

r, M

W

Simulation

Measurement

Ptrans(t) = conv (S12(t), sqrt(|P(t)|) * exp (i*(ω0*t+Δφ)) )

10

Simulation of the Energy Gain (no detuning)

0 10 20 30 40 50 60 70 80 90 1000

5

10

15

20

25

30

35

Peak Power, MWt

En

erg

y G

ain

, M

eV

CTF3, t=37CSimulation, f=0MHzSteady-state, f=0MHzCTF3, t=50CSimulation, f=0MHzCTF3, t=55CSimulation, f=0MHzCTF3, t=60CSimulation, f=0MHzSteady-state, f=0MHz

Vacc(t) = conv (RV(t), sqrt(|P(t)|) * exp (i*(ω0*t+Δφ(t))) )

11

Simulation of the Energy

0 10 20 30 40 50 60 70 80 90 1000

5

10

15

20

25

30

35

Peak Power, MWt

En

erg

y G

ain

, M

eV

CTF3, t=37CSimulation, f=9MHzSteady-state, f=9MHzCTF3, t=50CSimulation, f=6MHzSteady-state, f=6MHzCTF3, t=55CSimulation, f=5MHzSteady-state, f=5MHzCTF3, t=60CSimulation, f=4MHzSteady-state, f=4MHzSteady-state, f=0MHz

Vacc detuned (f) := Vacc (f - Δf), assuming that Δf=+10MHz at 30C and Δf = -1MHz/5C

12

Effect of the detuning in the comparison with the steady-state

0 50 100 150 200 250 300 350 400 4500

0.5

1

1.5

2

2.5

3

3.5x 10

7

Time, ns

Vo

lta

ge

, V

CTF3, df=0Steady-state, df=0CTF3, df=9MHzSteady-state, df=9MHz

Steady-state, df=9MHzCTF3, df=9MHz

13

Pulse-Surface Heating for 90MW CTF3 pulse vs CLIC nominal pulse

0 100 200 300 400 500 600 7000

5

10

15

20

25

30

35

40

45

Time, ns

T

, K

CLIC nominal, TCTF3, T

ΔT(t) = α * conv (1/sqrt(t), |P(t)|), normalization: ΔT (100ns, 100MV/m) = 28K

14

Conclusions

• Introducing detuning we’ve got rather good correlation between the simulations and measurements of the acceleration

• Pulse shape effect can also be clearly seen now, even though there is an interesting detuning effect

• There are still some calibration errors in the TBTS instrumentation

• Pulse-surface heating was comparable with the one for the CLIC nominal pulse