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Conditioning in RF structures

A. Degiovanni, J. Giner Navarro, W. Wuensch02-04-2014

CLIC RF Structure Development Meeting

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Conditioning history of two structures at KEK and CERN

• CERN TD26R05CC conditioning history plot 11168 BDs

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TD26R05 CC conditioned at CERN

61

301

pulsetBDRE

61

pulsetE

equivalent conditioning curve with constant pulse length of 250 ns since the beginning

equivalent conditioning curve with:- constant pulse

length of 250 ns since the beginning

- constant BDR of 1e-6 bpp/m

7e-05 2e-05automatic conditioning ON

It would take longer time to reach the same gradient with smaller BDR (as expected)

BDR[bpp]

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Conditioning history of two structures at KEK and CERN

• TD24R05#4 at KEK

T. Higo CLIC Workshop 2014

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TD24R05#4 conditioned at KEK - history

Conditioning BDR measurements

1060 BDs 591 BDs

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TD24R05#4 conditioned at KEK

61

301

0

pulsetBDRE

equivalent conditioning curve with:- constant pulse

length of 250 ns since the beginning

- constant BDR of 1e-6 bpp/m

6.6e-06 5.7e-06

2.8e-063.2e-06

1.6e-061.1e-06Conditioning curve

of TD24R05 at KEK

BDR[bpp]=

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BDR during conditioning

Moving average with a window of the last 10 MPulses

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Comparison of conditioning curves

gradient

normalized gradient𝐸0

𝑡𝑝−1 /6 BDR1/30

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Comparison of E0* vs #BD

Same conditioning level at different number of BD.

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Normalized gradient in LOG-LOG scale

Linear behaviour in this region, which means that conditioning can follow a power law

𝐸0∗∝𝑁 𝑝𝑢𝑙𝑠𝑒𝑠

𝑨

log (𝐸¿¿0∗ )∝ 𝑨 log (𝑁¿¿𝑝𝑢𝑙𝑠𝑒𝑠❑)¿¿

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Normalized gradient in LOG-LOG scale – Linear fit

A = 0.287 +/- 0.001

A = 0.2579 +/- 0.0006

𝐸0

𝑡𝑝−1 /6 BDR1/30

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Normalized BDR in LOG-LOG scale𝐵𝐷𝑅𝐸𝑎30 𝑡𝑝5

𝐵𝐷𝑅❑∗ ∝𝑁 𝑝𝑢𝑙𝑠𝑒𝑠

𝑨′

log (𝐵𝐷𝑅¿¿❑∗)∝ 𝑨 ′ log (𝑁¿¿𝑝𝑢𝑙𝑠𝑒𝑠❑)¿ ¿

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Normalized BDR in LOG-LOG scale – Linear fit

A’ = -8.35 +/- 0.02

A’ = -7.74 +/- 0.02

𝐵𝐷𝑅𝐸𝑎30 𝑡𝑝5

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EXTRA SLIDES

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Normalized Gradient𝐸𝑎

𝑡𝑝−1 /6 BDR1/30

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Normalized Gradient𝐸𝑎

𝑡𝑝−1 /6 BDR1/30

VS #RF Periods (tpulsex12GHz)

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Normalized Gradient

Overlapped

𝐸𝑎

𝑡𝑝−1 /6 BDR1/30

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Linear-Log and Log-Log scale plots

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Normalized Surface E field