6/12/2006 1

Test Facility Experimental ProgramILC Division RD report

June 12, 2006Marc Ross

ATF2 cavity BPMs

ATF nanoBPM system - nanoGrid

ATF2 Movers

TTF HOM – dipole / monopole

ESA/LCLS bunch length

ILCTA

4/24/2006 Marc Ross - SLAC 2

ATF2 Cavity BPM

• SLAC group will provide the full cavity system from the hybrid combiner to data server– 70 + channels

• Beam tests April 10 – 22.– Single ATF2 cavity between the two triplets (no mover)– First look is ‘good’– Data analysis started

• Full system delivery delayed – (was to have been June 5) – delay is mid-August.– Following discussions with group at ATF2 meeting– Our first cavity BPM System – Test result documentation (acceptance)– Mechanical– Calibration algorithm

4/24/2006 Marc Ross - SLAC 3

ATF2 Cavity BPM Production electronics

• 6 GHz receiver board layout• Realistic system design including packaging and mounting

hardware• Tested successfully at ATF April 2006

4/24/2006 4

LO locking chassis

CAL tone locking chassis

714MHz

2.16 MHz

BPM electronics box

BPM hybrid

ATF2 BPM System

RF coupler

Local configuration

System design

4/24/2006 Marc Ross - SLAC 5

Beam Tests of ATF2 electronics (Y. Honda)

4/24/2006 Marc Ross - SLAC 6

Beam Tests

4/24/2006 Marc Ross - SLAC 7

Beam Tests

4/24/2006 Marc Ross - SLAC 8

Schedule

4/24/2006 Marc Ross - SLAC 9

• 96 events at nominal position

• 64 events at +/-20 microns to calibrate

• Resolution, no nanogrids

19.1 nm

• Resolution, with nanogrids

15.6 nm

Do the Nanogrids Help?Data from 13 April 2006 at 22:56:

4/24/2006 Marc Ross - SLAC 10

ATF Laserwire

• extraction line near old Compton IP• requires special optics• need wire scanner to confirm

• backup lens – real one delayed and lost in the mail (Oxford)

• now testing fully corrected lens for operation in November

• two graduate students to be posted at ATF all year• Miryam Qureishi (Oxford) and Lawrence Deacon (RHUL)

• Guidance from Pavel Karataev (RHUL)

4/24/2006 Marc Ross - SLAC 11

ATF laser – wire scan (May 25)

• First scans• Optics and

laser aberrations

• (factor 10 scale error)

σ = 17.6 +/- 0.4 µm

4/24/2006 Marc Ross - SLAC 12

ATF2 Mover System

4/24/2006 Marc Ross - SLAC 13

Mover shipping and requirements:

4/24/2006 Marc Ross - SLAC 14

TTF HOM studies – plan for August

• Goals:– install and commission the HOM BPM DOOCs server– beam tests of HOM SVD algorithm– fast processor HOM board (FNAL)– HOM phase feedback

• 7 shifts; 2 weeks of beam time July 28 to August 13 – A lot of time allocated – 3 DESY, 5 Fermilab, 2 SLAC, 2 Saclay staff, ANL, JLab,

Cockroft. – Steve Molloy (SLAC) and Nathan Eddy (Fermi) working on

analysis

4/24/2006 Marc Ross - SLAC 15

Phase Measurement from Monopole modes

• Phase of monopole modes determined by beam phase. • Use fast (5GS/s, 6GHz BW) scope directly measuring

HOM signals• Compare HOM monopole phases with 1.3 GHz

reference– Not completely straightforward since TTF trigger jitter > 1 cycle of

1.3GHz

• Plot phase vs. machine cycle for TM011-7 and TM011-8, and phase difference between modes

• Note: measurent uses “accidental” data, taken during other experiment, not optimized.

4/24/2006 Marc Ross - SLAC 16

Higher Order Monopole Modes

• 2300 – 2500 MHz• Both couplers for 1 cavity shown• 0.1 degree (L-band) precision 0.2 ps

Note that different lines have different couplings to the 2 couplers

Monopole lines due to beam, and phase is related to beam time of arrival

Fundamental 1.3GHz line also couples out – provides precise RF to beam phase for control

4/24/2006 Marc Ross - SLAC 17

Beam Phase vs. RF Measurement During 5 Degree Phase Shift

Measure 5 degree phase shift commanded by control system

2 cavities, same structure give 0.34 degree L-band RMS phase difference

4/24/2006 Marc Ross - SLAC 18

What is System Resolution, Drift

Compare 2 couplers on same cavity, RMS difference 0.12 degrees L-band.

Electronics noise ~0.08 degreescavity to cavity difference (0.3 degrees may be due to microphonics)

Compare 2 cavities for long (7 hour) run. RMS difference 0.69 degrees L-band.

Combination of electronics drift and cavity to cavity phase shifts.

4/24/2006 Marc Ross - SLAC 19

Summary of Phase System Performance

• System noise ~0.08 degrees L-band, 1 minute timescales.– Also measured ~0.1 degree for 10 minutes

• Cavity to cavity difference ~0.3 degrees, possibly microphonics.

• Drift <0.7 degrees over 7 hours – probably dominated by real cavity to cavity variations.

• Cable length change of 10 degrees results in <0.25 degree (consistent with 0) change in measured phase

4/24/2006 Marc Ross - SLAC 20

ESA/LCLS bunch length monitor• This is a ‘single-pass’ device – intended as a

‘relative’ monitor to complement LOLA• Two devices to be built for LCLS BC1

– Deadline November 2006– Testing until November 2007

• ‘CSR’ or focused wave (BL11) and gap monitor (BL12)– Both may use pyroelectric devices– Beam tests in ESA this month– Accurate mm-wave measurements are difficult

• Full system relies on integration with LOLA (29-4)– No LOLA in ESA

4/24/2006 Marc Ross - SLAC 21

BL12 Bunch Length Monitor

• Located just after the BL11 monitor• Uses gap and diode detectors• Only vacuum component is conventional ceramic gap• Initially instrument with 100GHz diodes• Add higher frequency diodes as needed• Diodes used in pairs to reduce effect of beam motion• 20cm waveguide used to disperse pulse (~1ns), keep

peak power reasonable on diodes. • 20dB gain horns on diodes

4/24/2006 Marc Ross - SLAC 22

BL12

4/24/2006 Marc Ross - SLAC 23

BL12 Development Plan

• Similar diodes operating at 100GHz have been tested in End Station B. • Additional test in end station B in April 2006, using same electronics as

LCLS• Will use pair of diodes to check measurement noise.• Initial test in LCLS will be done with a pair of 100GHz detectors. • As shorter bunch length measurements are required, additional diodes and

waveguide can be added• Use of optical breadboard makes installation of new diodes (on optical

clamp mount) straightforward.• Will try using a pyroelectric detector mounted next to the gap.

– Should be able to measure total mm-wave power, and compare with toroid current measurement to get bunch length signal

– Very simple and inexpensive system if it works. – In principal extends to very short bunch lengths– Must be calibrated with LOLA

4/24/2006 Marc Ross - SLAC 24

100GHz Diode, WR10 waveguide and horn

WR10 and WR90 waveguidesat ceramic gap

ESA Bunch Length Monitor

• simple ceramic gap and diode detector

• diode and waveguide form crude bandpass filter

• 200 to 400 um bunch length sensitivity (ILC)

Two 100 GHz detectors track with RMS error of 1.5%

Summary – ongoing work and developments since April 2006

• ATF cavity BPM’s (UK, UCB, LLNL, KEK)– Near a spectrometer result with 2 triplets+1 (?)– Nanogrid tests – first results

• ATF2 BPM cavities (Pohang, KEK, UCL)– 1/3 copper cavities done– Electronics delayed 2 months system issues

• ATF extraction kicker (LLNL, KEK) delivered in June – To be used in September 2006

• TTF HOM (DESY, KEK, Saclay, FNAL)– System implementation in August– Phase measurements excellent (April 21)

• LCLS BLM– first results in May