Report from trip to ATF R. Toms CLIC seminar - 2008 Rogelio Tom - - PowerPoint PPT Presentation

Report from trip to ATF

• R. Tomás

CLIC seminar - 2008

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.1/20

Contents

• IP configuration
• Shintake monitor
• Honda monitor
• FONT: Fast Feedback system
• ATF2 FFS tuning simulations
• Flight simulator
• Damping Ring BPMs
• Measurement of resonance terms in the DR

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.2/20

IP configuration

t d

Shintake Sweeping Magnet Honda Monitor Carbon Wire Scanner

presented a

Monitor Area

• ✁

• ✄

• ☎

S-band BPM

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• ✆

• ☎

C-band BPM

• ✆

Screen Monitor

• ☎

200

Small

QD0

• ✂

IP

IP-BPM

• ☎
• ✂

Very cluttered IP area!!

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.3/20

Shintake monitor

New Shintake monitor with extra laser channels with larger angle to extend the measurable size range up to the 5µm.

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.4/20

Honda beam size monitor

New conceptual beam size monitor to be tested and used in ATF2, the range is 0.3-2µm

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.5/20

FONT: Fast Feedback system

FB off FB off

nts)

154ns

DC cou

FB on

tion (AD

FB on

am Posi

‘banana’ effect

corrected!

Bea

P.N. Burrows ATF2 meeting, KEK, 19/12/07 13

banana effect corrected!

Oxford + Daresbury managed to prove 140ns latency feedback!

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.6/20

ATF2 FFS tuning simulations I

• G. White predicts one week of tuning for achieving

≈35nm vertical spot size.

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.7/20

ATF2 FFS tuning simulations II

2 4 6 8 10 12 500 1000 1500 2000 2500 3000 3500 Counts Number of iterations

• A. Latina and myself predicted 3 days of tuning with

more optimistic assumptions.

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.8/20

Flight Simulator

• The machine should be operated by computers
• Algorithms should be tested with simulations
• Code philosophy: any code should be usable

(SAD, MAD, Lucretia, PLACET, etc)

• G. White has built a server that would

communicate with the machine from any code.

• We are very interested on using PLACET!

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.9/20

Damping Ring BPMs

36 13 15 38 36 40 42 7 9 11 13 44 42 46 3 5 7

48 52 50 93 95 1 52 56 93

8 BPMs Feb07

54

12x BPMs May07 CAL signal May07 CAL prototype test Dec07 (extra VME crate)

FNAL people are installing turn-by-turn electronic boards for the BPMs.

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.10/20

Measurement of resonance terms

0.01 0.02 0.03 0.04 0.05 60 70 80 90 100 110 120 Line(-2,0)/Line(1,0) Longitudinal location[m] Oscillation amplitude: 2.25mm at start of ATFDR Experiment (06apr11-033144) Simulation (with decoherence)

ATF report 06-08 2006 experience

Horizontal resonance (3,0) successfully probed via spectral line -2Qx. However vertical plane totally unprobed.

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.11/20

Spectrum from November’s data

5 10 15 20 25 30 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5 Amplitude Frequency [tune units] Vertical spectrum BPM47 (amplitude= 82 units) Qy Qx 2Qy? 2Qs?

Qx line comes from linear coupling. 2Qy line related to resonance (0,3). This resonance is driven by skew sextupoles.

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.12/20

Coupling: December’s tune scan

• ✁

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• ✂✁

• ✁

• ✁

• ✁

• ✁

• ✁

• ☎

• ☛

Average coupling = 2.5% ± 0.3%, (quite flat).

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.13/20

Skew sextupolar resonances

• Skew sextupoles produce non-linear coupling that

deteriorates ǫy, trough the term yx2.

• The nearest skew resonance to the ATF tunes is

(2,1)

• and its spectral line is 2Qx in the vertical plane.
• Can we measure it?

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.14/20

Skew resonance (2,1): December’s tune scan

• ✂✁

• ✁

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• ✂✁

• ✁

• ✁

• ✁

• ✁

• ✁

• ✁

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• ✁

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• ✄

• Rogelio

Tom´ as Garc´ ıa Report from trip to ATF – p.15/20

New BPMs

10 20 30 40 50 60 70 0.1 0.2 0.3 0.4 0.5 Amplitude [µm] Frequency [tune units] Spectrum of Vertical New BPM #44 Qx Qy 2Qx Qx+Qy Garbage

New DR BPMs are still under commissioning. They have low frequency noise and synchronization problems, but let’s look!

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.16/20

New BPMs, 2Qx line around the ring

• ✁
• ✂
• ✄
• ☎
• ✆
• ✝

• ✆

This might indicate source of skew sextupolar fields

• r faulty BPM...

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.17/20

Correction

• Linear coupling can be corrected with existing

skew quads.

• Non-linear coupling correction can be achieved

in two ways:

• Localization of source and direct fix
• or needs installation of skew sextpoles.

Before action, estimates on ǫy improvement should be computed.

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.18/20

Coupling correction simulation

• 0.2
• 0.15
• 0.1
• 0.05

0.05 0.1 0.15 0.2 20 40 60 80 100 W- BPM # W- Real (uncorrected) Real (corrected) Imaginary (uncorrected) Imaginary (corrected)

(identical to f1001)

• E. Gianfelice and Y. Alexain propose simultaneous

correction of coupling and vertical dispersion at the BPMs to get lowest ǫy in the ATF DR.

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.19/20

Summary

• A good fraction of LC technology is being tested

in ATF/2

• We should use this facility to test CLIC concepts
• Measurement of resonance terms might improve

electron rings performance

Rogelio Tom´ as Garc´ ıa Report from trip to ATF – p.20/20