1. ILC Beam Tests in End Station A
ILC R&D Meeting, Dec. 18, 2006
M. Woods, SLAC
BPM energy spectrometer (T-474/491)
Synch Stripe energy spectrometer (T-475)
Collimator design, wakefields (T-480)
Bunch length diagnostics (w/ LCLS, T-487)
IP BPMs/kickers—background studies (T-488)
LCLS beam to ESA (T490)
Linac BPM prototypes
EMI (electro-magnetic interference)
M. Woods, SLAC

2. ILC Beam Tests in End Station A
6 test beam experiments approved: T-474/491, T-475, T-480,
T-487, T-488, T-490
2006 Runs:
January 5-9 commissioning run
April 24 – May 8, Run 1
July 7-19, Run 2
2007 Runs (dates tentative):
March 7-26, Run 3
July 5-8, T490 w/ LCLS beam
July 9-22, Run 4
+ requesting two 2-week runs in FY08
M. Woods, SLAC

3. ILC Beam Tests in End Station A
3 posters/papers presented at EPAC06:
M. Woods et al., “Test Beam Studies at SLAC End Station A, for the International Linear Collider,”
SLAC-PUB-11988, EUROTEV-REPORT , EPAC-2006-MOPLS067.
www-project.slac.stanford.edu/ilc/testfac/ESA/files/EPAC06/SLAC-PUB pdf
N. Watson et al., “Direct Measurement of Geometric and Resistive Wakefields in Tapered
Collimators for the International Linear Collider,” SLAC-PUB-12029, EUROTEV-REPORT ,
EPAC-2006-MOPLS
G. Christian et al., “The Electromagnetic Background Environment for the Interaction-point Beam
Feedback System at the International Linear Collider,” EUROTEV-REPORT ,
EPAC-2006-THPCH08.
9 abstracts submitted to PAC 07
T-474 (2), T-480 (3), T-488 (2), T-Bunchlength (1), T-EMI (1)
Status Report on ILC-ESA Test Beam Program to SLAC EPAC Dec. 5
M. Woods, SLAC

4. ESA Equipment Layout blue=FY06 red=new in FY07 Wakefield box
Wire Scanners
FONT-T488
rf BPMs
18 feet
Ceramic gap BLMs
T-487: long. bunch profile
Dipoles + Wiggler
Upstream (not shown)
Downstream (not shown)
4 rf BPMs for incoming trajectory Ceramic gap w/ rf diode detectors (16GHz, 23GHz, and 100GHz) and 2 EMI antennas
Ceramic gap for EMI studies T475 Detector for Wiggler SR stripe
M. Woods, SLAC

5. Energy Spectrometer Magnets
for 2007 Runs
1 Dipole currently at Magnet Test Lab
1 Dipole is installed on ESA Beamline
M. Woods, SLAC

6. T474: Resolution & stability within a BPM triplet
old cavities
200 nm =
40 ppm
Resolution : BPM 9-11: ~350 nm in x
BPM 3-5: ~ 700 nm in x,
<40 ppm stability for 20k pulses ~ 30 min
2006 Results
(Preliminary)
prototype
M. Woods, SLAC

7. T474: Resolution & Stability Linking BPM Stations in ESA
Run 1333
Wake-
Field
Box
4 chicane magnets will
go in this region
30 meters
use BPMs 1-2 and 9-11 to fit straight line
predict beam position at BPMs 3-5
plot residual of BPM 5 wrt predicted position
0.5mm → 100 ppm
Why jumps and drifts in residuals
when linking bpm stations?
Investigate possibilities:
analysis bug?
changes in LO phase or BPM electronics?
bias related to change in beam trajectory,
beam energy or other beam parameters?
relative alignment of bpm stations changed?
Run 1333
→ a primary purpose of T-474 is to investigate sensitivity
of energy measurement to changes in beam
parameters and electronics stability, and whether
goals for systematic errors <100ppm can be met
2006 Results
(Preliminary)
M. Woods, SLAC

8. T474: Resolution & Stability Linking BPM Stations
→ better stability on this run!
Run 1458
Run 1458
Run 1458
Run 1458
2006 Results
(Preliminary)
M. Woods, SLAC

9. Energy Spectrometer Tests: FY07/08 Plans
Performance tests of realistic spectrometers
Investigate calibration procedures and systematics due
to BPM electronics stability, mechanical stability,
magnetic fields, sensitivity to beam parameters
compare results from BPM, synch stripe msmts and
upstream beam diagnostics
Install 4 chicane magnets and 1 wiggler
Move BPM4 to BPM6 location
New BPM7, design optimized for spectrometry
Operate chicane in both polarities
Install Metrology grid (staged approach)
Install Detector for Wiggler SR stripe
BPM 3,5
BPM 6,7
BPM 9-11 D1 D2 D3
Vertical
Wiggler D4
Metrology Grid straightness monitor
BPM Station
Interferometer arms
~1m
“reference bar” for triangulation. Contains internal interferometer for monitoring
M. Woods, SLAC

10. Energy Spectrometer Tests: FY07/08 Plans
Performance tests of realistic spectrometers
Investigate calibration procedures and systematics due
to BPM electronics stability, mechanical stability,
magnetic fields, sensitivity to beam parameters
compare results from BPM, synch stripe msmts and
upstream beam diagnostics
Install 4 chicane magnets and 1 wiggler
Move BPM4 to BPM6 location
New BPM7, design optimized for spectrometry
Operate chicane in both polarities
Install Metrology grid (staged approach)
Install Detector for Wiggler SR stripe
BPM 3,5
BPM 6,7
BPM 9-11 D1 D2 D3
Vertical
Wiggler D4
3D2
Beam
R. Arnold
M. Woods, SLAC

11. T-480 Preliminary Results
Sandwich 1 Collimators:
a = 324 mrad
r = 1.9 mm
L=1000 mm
Slot 1
Slot 3
(r = ½ gap)
a = 324 mrad
r = 1.4 mm
a = 324 mrad
r = 1.4 mm
a = p/2
r = 3.8 mm
Slot 2
Slot 4
7mm
M. Woods, SLAC

12. Kick Factor V/pc/mm (c2/dof)
T-480 Preliminary Results
Collimator
Measured4
Kick Factor V/pc/mm (c2/dof)
Linear fit
Linear + Cubic Fit
Analytic Prediction1
Kick Factor V/pc/mm
3-D Modelling
Prediction2
Kick Factor
V/pc/mm
1 (Sand1,Slot1)
1.4 ± 0.1 (1.0)3
1.2 ± 0.3 (1.0)
1.1
1.7
2 (Sand1,Slot2)
1.4 ± 0.1 (1.3)
1.2 ± 0.3 (1.4)
2.3
3.1
3 (Sand1,Slot3)
4.4 ± 0.1 (1.5)
3.7 ± 0.3 (0.8)
6.6
7.1
4 (Sand1,Slot4)
0.9 ± 0.2 (0.8)
0.5 ± 0.4 (0.8)
0.3
0.8
5 (Sand2,Slot1)
1.7 ± 0.3 (2.0)
1.7 ± 0.3 (2.2)
2.4
6 (Sand2,Slot2)
1.7 ± 0.1 (0.7)
2.2 ± 0.3 (0.5)
2.7
7 (Sand2,Slot3)
0.9 ± 0.1 (0.9)
0.9 ± 0.3 (1.0)
8 (Sand2,Slot4)
3.7 ± 0.1 (7.9)
4.9 ± 0.2 (2.6)
6.8
1Assumes 500-micron bunch length
2Assumes 500-micron bunch length, includes analytic resistive wake; modelling in progress
3Kick Factor measured for similar collimator described in SLAC-PUB was (1.3 ± 0.1) V/pc/mm
4Still discussing use of linear and linear+cubic fits to extract kick factors and error bars
→ Goal is to measure kick factors to 10%
M. Woods, SLAC

13. T-480: FY07/08 Plans
7 New Collimators for Run 3 will be fabricated and tested
(keep 1 from Run 2 for cross check)
Compare importance of tapers in region away from gap centre –
acceptable to have shallow tapers necessary for transverse wakefield performance only in the immediate vicinity of beam axis??
(Can we make much shorter collimators?)
Flat section introduced equivalent in length to 0.6 r.l. of Ti6Al4V
Explicit tests of surface roughness
Allow one slot for non-linear taper, exponential form
Additional Collimators to test for Run 4 possible in FY07
+ plan to continue tests in FY08
M. Woods, SLAC

14. Bunch Length Measurements
vs Linac rf Phase
Energy Spread
100GHz Diode*
short bunches w/
small energy spread
Shorter bunches
LiTrack Simulation
Data
Pyroelectric Detector*
→ sensitive to shorter
bunches than
100GHz diode!
23GHz Diode*
→ insensitive to bunch length
*normalized
to toroid
M. Woods, SLAC

15. Bunch Length Studies for 2007
1. Will continue collaborative effort with LCLS
test 300-GHz diode detector
test large area pyroelectric detectors
discussing with F. Sannibale and M. Zolotorev at LBL & J. Frisch at SLAC
possibility for bunch length measurements from analyzing statistical fluctuations
in visible synchrotron radiation from T-475 wiggler magnet in energy spectrometer
chicane
→ do this with T-490 beam?
(this technique described in PRL 82, 5261 (1999) for 1-5ps bunches at 44 MeV)
2. T-487 experiment with Smith-Purcell radiation
M. Woods, SLAC

16. T487: Longitudinal Bunch Diagnostics
for the ILC
Goal: non-invasive determination of longitudinal bunch profile
Fundamental beam quantity; important for beam-beam effects.
Technique: Use Coherent Smith-Purcell radiation, emitted when a beam passes close to a
periodic structure (i.e. a metallic grating).
Grating produces dispersion of the wavelengths according to the angle of observation.
Wavelength distribution of emitted coherent radiation depends on the temporal profile of the bunch
Carousel of Gratings
Simple experimental set-up:
‘Carousel’ of 3 gratings with different periodicities.
Array of 11 room temperature pyroelectric detectors covering angular
range 40 – 140o w.r.t. the beam direction.
Winston Cone
Optical system:
Waveguide Array Plate filter designed for a
specific wavelength, attached to a light
concentrator (Winston cone).
Filter and Winston cone suppress
background radiation, while collecting and
concentrating desired wavelengths onto
the pyroelectric detectors.
Front View
Waveguide Array Plate Filter
M. Woods, SLAC

17. T487: Longitudinal Bunch Diagnostics
for the ILC
PI: G. Doucas (Oxford U.),
Collaborating Institutions: U. of Oxford, Rutherford Appleton Lab,
U. of Essex, Dartmouth College, SLAC
T-487 at SLAC-ESA
access to a much higher energy beam, with a different bunch structure to previously used beams.
An improved electronics system has been implemented, separating the electronics from the detectors,
so as to reduce X-ray interference.
Due to the higher energy and charge of the SLAC-ESA bunch, higher orders of Smith-Purcell
radiation may be exploitable.
Data obtained from higher orders will extend the measured range of wavelengths and
provide useful insights into Smith-Purcell theory itself.
New filters have been produced to explore these regions with our current gratings.
An analysis code is being developed, which will include Kramers-Kronig phase determination, in order
to obtain a unique bunch profile from the measurements.
Envisage two experimental runs at ESA in 2007 and two in 2008.
M. Woods, SLAC

18. this ILC Test Beam Program?
Future for continuing
this ILC Test Beam Program?
FY08 → continue program in ESA, requesting 4 weeks of Beam Tests
→ beam scheduling more difficult: priority for LCLS, also for SABER
→ reduced funding available (?) from SLAC and ILC, but major installations are complete
FY09 and beyond (LCLS era, parasitic operation with PEP-II ends at end of FY08)
→ ESA PPS upgrade needed for continued ESA operation
→ ILC beam instrumentation tests in SABER are possible
→ Study group looking at SLAC test beam capabilities with primary and secondary beams
for Detector and MDI-related R&D -- topic for Fermilab ILC Detector Test Beam Workshop in January
SABER - assume SABER exists with bypass line and operational for beam tests by 2010
- parameters for primary beam can be similar to ILC for bunch charge, energy spread,
bunch length GeV energy.
- limited space and infrastructure
- should be able to carry out small scale tests, ex. tests for BPMs, bunch length detectors
- unlikely to continue T-474/T-475 here; T-480 may be possible, but difficult
- need to investigate capability for low-intensity secondary beams for ILC detector R&D
ESA
several possibilities exist for primary and secondary beams to ESA in LCLS era; most
require PPS upgrade and some require pulsed magnets in Beam Switchyard
primary beam modes: i) high energy beam when LCLS not running, iii) extend SABER bypass line
to ESA (expensive), iii) interleaved 10Hz running using LCLS beam with pulsed magnets,
secondary beam modes: i) high energy beam when LCLS not running, ii) parasitic operation with LCLS
using beam halo and production collimator in BSY, iii) extend SABER bypass line to ESA (expensive),
iv) pulsed magnets in BSY using 10Hz LCLS beam and BSY production collimator,
M. Woods, SLAC

19. Future of SLAC Test Beams
(cont.)
New SABER Task Force following the DOE and EPAC SABER reviews
revisit comparison between South Arc and B Target Room locations,
+ consider broader user community, in particular for ILC
need to give input to task force for ILC Detector, Accelerator and MDI
Also, informal study group considering SLAC Test Beam capabilities
and user needs for Detector and MDI-related Beam Tests
preparing internal working document on this
will participate in Fermilab ILC Detector Test Beam Workshop
ILC Detector Test Beam Workshop, Fermilab Jan
C. Hast, D. MacFarlane and M. Woods will attend
Carsten will give talk in Facilities session,
“SLAC Beam Test Facility Status and Plans”
Mike will give talk in Beam Instrumentation and MDI session,
“Experiments at ESA, SLAC”
3 other talks in this session will also include information on the
ESA test beam program (energy spectrometers, FONT, collimator R&D)
M. Woods, SLAC

20. (presented to EPAC review Dec. 5)
Summary
(presented to EPAC review Dec. 5)
Very successful program in 2006!
4 weeks of beam tests for 7 experimental programs
50 participants (32 users + 18 SLAC) from 18 institutions
T-480 Collimator Wakefield Study
Results essential for ILC collimator design
Minimize risk for emittance degradation to IR and for achieving design luminosity
T-474 and T-475 Energy Spectrometer Prototypes
Experimental results needed to demonstrate ability to meet design
goals for precise energy measurements for the ILC physics program.
FY07 → strong program, with 5 weeks of Beam Tests planned
FY08 → continue program, requesting 4 weeks of Beam Tests
→ beam scheduling more difficult: priority for LCLS commissioning, also for SABER
→ reduced funding available (?) from SLAC and ILC, but major installations are complete
FY09 and beyond (LCLS era, parasitic operation with PEP-II ends at end of FY08)
→ ESA PPS upgrade needed for continued ESA operation
→ ILC beam instrumentation tests in SABER possible; need to investigate secondary beams
→ Study group looking at SLAC test beam capabilities with primary and secondary beams
for Detector and MDI-related R&D (topic for Fermilab ILC Detector Test Beam
Workshop in January)
M. Woods, SLAC