1. Carsten Hast User Facilities for HEP and Photon Science at SLAC
FACET ● NLCTA ● ASTA ● ESTB
Carsten Hast
SLAC National Accelerator Laboratory
John Adams Institute, Oxford, UK, September 2010
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

2. Carsten Hast - ARD Test Facilities Department
FACET
ESB &
NLCTA
ESA
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

3. SLAC Test Facilities’ Goals
High Energy Physics
Support Research for Linear Collider
High and Ultra High Gradients
Plasma Acceleration
Direct Laser Acceleration
Machine Detector Interface Studies
Detector Development
LC Detectors
B-Factories
Others
Photon Science
Gun Development
New Materials
New Designs
Different Frequencies
Novel Seeding Techniques for FELs and other FEL Fundamentals
Echo Enabled Harmonic Generation
Emittance exchange
THz Radiation
etc.
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

4. Carsten Hast - ARD Test Facilities Department
Let’s talk about:
How to make a Linear Collider shorter
Higher Gradients (ASTA, NLCTA)
New Acceleration Techniques
Plasma Wakefield (FACET)
Direct Laser (NLCTA)
How to make FELs “better”
Brighter Guns (ASTA, NLCTA)
Coherent laser light (seeding) (NLCTA)
…and more…(ESA, ESB)
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

5. Beam Driven Plasma Wakefield Accelerator
Two-beam, co-linear, plasma-based accelerator
Plasma wave/wake excited by relativistic particle bunch
Deceleration, acceleration, focusing by plasma
Accelerating field/gradient scales as ne1/2
Typical: ne≈1017 cm-3, λp≈100 µm, G>MT/m, E>10 GV/m
High-gradient, high-efficiency energy transformer
* Get us all on the same page
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

6. E-167: Energy Doubling with a Plasma Wakefield Accelerator @ FFTB
Acceleration Gradients of ~50GeV/m (3,000 x SLAC)
Doubled energy of 45 GeV electrons in 1 meter plasma
Single Bunch
Nature Feb-2007
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

7. Many FACET transparencies courtesy of Mark Hogan7
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department
M.J. Hogan, FACET Users Workshop March 18-19, 2010, Page

8. Beam Parameters Driven by Science Needs
SLAC
FACET Sector 10
FFTB < 2006
FACET
Sector 20
FACET Beam Parameters
Energy
23 GeV
Charge
3 nC
Sigma z
14 µm
Sigma r
10 µm
Peak Current
22 kAmps
Species
e- & e+
Beam Parameters Driven by Science Needs
Delivered to 100m area with three distinct functions:
Chicane for final stage of bunch compression
Final Focus for small spots at the IP
Experimental Area
Advantageous location:
Preserves e+ capability
No bypass lines or interference with LCLS
Linac setup virtually identical to SPPS/FFTB
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

9. FACET Uses a Three Stage Compression Processb a c d e f g
end of FACET sector 20 chicane
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

10. Carsten Hast - ARD Test Facilities Department
Generate Two Bunches by Selectively Collimating During Bunch Compression Process
Exploit Position-Time Correlation on e- bunch to create separate drive and witness bunch
Modeled using similar analytic framework (CSR) as LCLS as well as tracking/shower codes
x ∝ ΔE/E ∝ t
Disperse the beam in energy
Adjust final compression
...selectively collimate
x [mm]
dp/p [%]
z [mm]
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

11. Carsten Hast - ARD Test Facilities Department
FACET Design is Forward Looking and Flexible e.g. Sailboat Chicane Upgrade
Extract e- & e+ from damping rings on same linac pulse
Accelerate bunches to sector 20 while 5cm apart
Use ‘Sailboat Chicane’ to put them within 100µm at entrance to plasma
Large beam loading of e- wakes with high charge e+ beams
Opens up many new avenues of research:
Positron acceleration on electron driven wakes
Positron Driven-PWFA
Fast magnetic switching with delay between opposite field signs
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

12. Carsten Hast - ARD Test Facilities Department
FACET Experiments
Plasma Wakefield Acceleration
PW Acceleration of positrons
Positron driven plasmas
Ultrafast magnetic switching experiments
After burner studies based on stimulated emission of radiation
Many technical questions for future linacs based on wakefield acceleration will be addresses (Optical diffraction, Smith-Purcell Radiation...)
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

13. Please keep them coming!
FACET Status
Approved, funded (not enough…) and under construction
Construction schedule will allow first electron beam May / June 2011
Need to checkout and establish decent beams June / July
Run beam for users starting July or August
4 month of user runs per year for the next 5 years
FACET will provide 23 GeV electron and positron beams with 20 kA peak current with spot size of 10x10 microns
Integrated many experimentally diagnostics into FACET facility (BLM, OTRs, X-ray stripe) for improved reliability and shared benefit
Beam parameters are flexible and adaptive to a wide range of users
Good access for people and equipment
Flexible area for experimenters with space to accommodate new hardware/ideas
First round of proposals was received, but:
Please keep them coming!
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

14. Carsten Hast - ARD Test Facilities Department
End Station B (ESB)
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

15. Carsten Hast - ARD Test Facilities Department
ESB
NLCTA
TTF Couplers
Marx Modulator
X-Band
Plasma Switches
L-Band
Laser
E-163 DLA
S-Band Gun
Echo-7
RF Testing
XBTA
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

16. Carsten Hast - ARD Test Facilities Department
NLCTA
45m long, e- beam, MeV (maybe 400 later), xy-emittance
1 to few microns, bunch length 0.5 psec, pC, dp/p≤10-4
LCLS style S-Band Injector
10 GW-class Ti:Sapphire system (800nm, 4 mJ)
KDP/BBO Tripler for photocathode (266nm, 0.4 mJ)
Active and passive stabilization techniques
5 GW-class Ti:Sapphire system (800nm, 1.2 mJ)
For E-163 and Echo-7
100 MW-class OPA ( nm, mJ)
5 MW-class DFG-OPA ( ,000 nm, 1-3 mJ)
Bend to Experimental Hall (currently E-163 DLA)
Laser Seeding Test Area (currently Echo-7 Echo Enabled Harmonic Generation )
Lots of diagnostics
Two x-band RF test stations for High Gradient research
X-Band Test Area (X-Band gun and 100 MeV accelerator next year)
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

17. NLCTA Experimental Hall: E-163
Direct Laser Acceleration
High gradient, power-efficient, economical acceleration  high energy physics and industrial applications
Attosecond pulse generation from point-like sources  photon science applications
Transition Radiation Accelerator stage
Undulator + Chicane Optical Buncher
First Staging of Laser Accelerator Sections
Beam
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

18. E-163: Beam Tests of Microstructures
Several types of accelerator structures to be tested
Photonic Bandgap Fiber
e-beam profile image
at PMQ focus
SEM image of HC-1550 fiber
ThorLabs HC
10 µm
Planar-Waveguiding
8 x 8 µm RMS
Achieved about 10 MeV/m
(but the structures are tiny…)
Goal is ~1GeV/m and having multiple stages
Planar-Grating
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

19. NLCTA: X-Band Accelerator
Length:
75 cm
Operating gradient:
80 MV/m
Max gradient: 100 MV/m
Our plan is to make NLCTA an X-Band show case:
higher energy, better beams
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

20. High Gain Harmonic Generation (HGHG)
NLCTA: FEL Seeding
High Gain Harmonic Generation (HGHG)
laser
Laser beam interacting. First undulator tuned to amply this interaction called a modulator. Chicane r56 moves modulations together. dE = laser modulations, E being the beam energy. Second undulator tuned to nw to amplify this harmonic
Energy modulation in the modulator
Energy modulation converted to density modulation 20
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 20

21. Echo Enabled Harmonic Generation
EEHG
HGHG
seed
laser 2
laser 1
Extend the HGHG scheme with another modulator and chicane. N,m can be negative. Challenge is to preserve this phase space correlations
First laser to generate energy modulation in electron beam
First strong chicane to split the phase space
Second laser to imprint certain correlations
Second chicane to convert correlations into density modulation
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 21

22. EEHG FEL: Promises and Challenges
Promises (in theory)
Remarkable up-frequency conversion efficiency allows the generation of soft X-rays from UV seed lasers in a single stage
Peak currents are NOT significantly enhanced, which mitigates collective effects
Challenges
Control & preservation of the phase space correlations
CSR & ISR in the chicanes
Quantum diffusion in the undulators from ISR
Path length difference for particles with different betatron amplitude
Unwanted x-z coupling from field errors, high order field components
Small payments
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 22

23. Carsten Hast - ARD Test Facilities Department
ECHO-7 at NLCTA
existing
New ECHO beam line
Install X2 to boost beam from 60 MeV to 120 MeV
Laser transport
Construction of three undulators, three chicanes
Add new or move existing quadrupoles, correctors, etc.
New power supplies
New diagnostics: OTRs, YAGs, cameras, movers, DAQ
Add beam line spectrometer dipole 23
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 23

24. Carsten Hast - ARD Test Facilities Department
Echo-7 Beam Line
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

25. Parameters of ECHO-7 (July 2010)
Beam Energy
120 MeV
Bunch length
0.5 ps
Normalized Emittance
8 mm-mrad
Bunch charge
20-40 pC
Laser wavelength in U1
795 nm
NIR
Laser wavelength in U2 (seed)
1590 nm IR
Slice energy spread
~ 1 keV
Np x lu for U1
10 x 3.3 cm
K=1.82
Np x lu for U2
10 x 5.5 cm
K=2.09
Np x lu for U3
10 x 2 cm
Peak energy modulation in U1 and U2
10-40 keV
R56 for C1 and C2
1.0 ~ 9.0 mm
Radiation wavelength in radiator
>318 nm UV
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 25

26. Carsten Hast - ARD Test Facilities Department
Spatial overlap
Beam on OTR1
Beam on OTR2
OTR1
OTR2
The spatial overlap is achieved by steering the laser to the same position as the electron beam on the OTR screens upstream and downstream of the undulators
Laser on OTR1
Laser on OTR2
Additional trans for otr hardware and specs.
107 attenuation
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 26

27. Wavelength calibration
Incoherent undulator radiation
1590 nm laser on
(a)
795 nm laser on H2
(b)
395 nm bandpass filter in
531 nm bandpass filter in
Precursor transp about what we expect to measure and how. Bandwidth limitation. Enough periods to see signal.
The radiation spectrum [350, 600] nm can be measured in a single shot 27
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 27

28. First ECHO signal! H2 E-1,5 H2 (a) (b) (c) 350 400 450 500 550 600
1590 nm laser only
But attenuated
No HGHG
(a)
795 nm laser only
HGHG signal H2
(b)
Both lasers on with no 1590 nm HGHG
(c)
Pictures from the actual experiment. Attenuated 1590 to kill HGHG. Tiurned on 795 nm only (no 530 nm). Both on but with 1590 attenuated no HGHG . Spot at 530 belived to be echo.
E-1,5 H2
350
400
450
500
550
600
Radiation wavelength (nm) 28
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 28

29. ECHO signals when beam has an energy chirp
Radiation wavelength (nm) H2
1590 nm laser on
795 nm laser on
HGHG
HGHG + EEHG E1 E2 E3
350
400
450
500
550
600 H4 H3
1590 nm seed laser on
Both lasers on
HGHG and combined spectra changes. More echo signals come out of hiding.
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 29

30. EEHG comparison with Monte Carlo Published PRL in August
350
400
450
500
550
600 H4 H3 H2
Both lasers on
(b)
simulation
Simulation matches the data except for the mystery peaks.
Published PRL in August
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department 30

31. Your ideas and contributions are most welcome
NLCTA Plans
Improve NLCTA
Control System, more uniform DAQ
Better beam diagnostics
Fix Phase jitter (between klystrons and lasers)
And many more
Ongoing Program
Repeat Echo 2-4
Continue E-163
Continue X-Band RF tests
New Experiments
Echo 7-15
Narrow-band beatwave THz emission
Studies COTR properties and micro-bunching instabilities
Install transverse cavities for increased slice energy spread and redo EEHG
Emittance Exchange with transverse cavities
FEL gain (use an LCLS undulator)
RF Undulator test with and without beam
Increase beam energy up to 400 MeV
and more…
New X-Band Test Area for structure testing and an X-Band gun and 100 MeV linac
Your ideas and contributions are most welcome
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

32. Application example: Soft X-Ray Linac
Ultra High Gradients
Goal is to design a “conventional” accelerator with loaded gradients of 150MeV/m (~7 times SLAC linac)
Material and geometry simulations, fabrication and of course testing (ASTA and NLCTA)
Achieved working beam loaded structures of 100MeV/m (routinely operating 80MeV/m structure in NLCTA)
Application example: Soft X-Ray Linac
~40m ~30m Based on X-Band with 100MeV/m
50m m Based on SLAC Linac 20MeV/m
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

33. ASTA Test Facility 50 MeV e-beam capability RF component testing
Rapid modifications possible
Working on modernization of control system and a more universal LLRF system
Future photocathode R&D
New Laser Room
Gate Valves
Variable Delay line length through variable mode converter
RF in from two 50 MW Klystrons
Two experimental stations inside the bunker, one with compressed pulse and the other without the benefit of the pulse compressor.
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

34. ASTA has a “bright” future
ASTA Test Facility
High Gradient RF development (ongoing)
Two XL-4 X-Band klystrons with pulse length up to 1.5 us
Very flexible X-Band RF pulse compression system
compressing the combined power from both klystrons
producing a variable pulse from 1.5 us to 62 ns
output powers from 100 MW to > 600 MW
Thermionic electron gun is available
Cathode and Gun research for high brightness low emittance electron sources (future)
One S-Band and both X-Band klystrons
New laser system for the cathode and gun tests
ASTA has a “bright” future
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

35. End Station A Test Beam (ESTB)
Test beam activities have been interrupted by ending PEP II operation and start of LCLS
ESTB will be a unique HEP resource
World’s only high-energy primary electron beam for large scale Linear Collider MDI and beam instrumentation studies
Exceptionally clean and well-defined secondary electron/positron beams, secondary hadron beams, and photon beams available for detector development
Huge experimental area, good existing conventional facilities, and historically broad user base
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

36. Kick 13.6 GeV LCLS beam to ESA
ESA Test Beam provides electrons up to GeV at full beam intensity…
Kick 13.6 GeV LCLS beam to ESA
2 - 6 x 109 e-/pulse @ 5 Hz
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

37. Carsten Hast - ARD Test Facilities Department
… Electrons/Hadrons up to GeV, from single particles to full beam intensity
Clean secondary electrons/positrons p<13.6 GeV, 0.1/pulse to 2 x 109 e-/p
Secondary hadrons (later stage) ~1  / pulse < 12 GeV/c
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

38. Carsten Hast - ARD Test Facilities Department
ESA Experimental Area
Beam
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

39. Carsten Hast - ARD Test Facilities Department
ESA Infrastructure
Available Instrumentation Trigger counters
Halo veto counters
High resolution beam hodoscope
Particle ID (Cerenkov, TOF, shower counter)
Small, high field solenoid
sturdy support table with remote movers
Cranes 15 and 50-ton cranes available
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

40. ESA Primary Beam Equipment Layout
18 feet
Wakefield box
Wire Scanners
rf BPMs
T-487: long. bunch profile
“IP BPMs” T-488
Ceramic gap
for EMI studies
BPM energy spectrometer (T-474/491)
Synch Stripe energy spectrometer (T-475)
Collimator design, wakefields (T-480)
Bunch length diagnostics (T-487)
Smith-Purcell Radiation
IP BPMs—background studies (T-488)
LCLS beam to ESA (T490)
Linac BPM prototypes
EMI (electro-magnetic interference)
Irradiation Experiments
Dipoles + Wiggler
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

41. Secondary Electrons and Positrons
Inserting a thin foil in the transport line to ESA, and using the beamline as a spectrometer, creates a clean secondary electron/positron beam over the full range of energies
(<13.6GeV) and a wide range of intensities down to ~1/pulse
x,y~ 1 mm
p/p ~  1%
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

42. from Jerry Va’vra’s Focusing DIRC Tests…
SLAC 10 GeV/c electron beam
Beam enters bar at 90º angle.
Prototype is movable to 7 beam positions along bar.
Time start from the LINAC RF signal, but correctable with a local START counter
Beam spot: s < 1mm
Lead glass:
Local START time:
s ~36ps
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

43. KPiX64-4 BNL, UC Davis, Oregon, SLAC Power-pulsed ILC readout chip
From Timothy Nelson (ILC-SiD) 43
KPiX64-4
BNL, UC Davis, Oregon, SLAC
Power-pulsed ILC readout chip
Three vertically oriented planes
Not a telescope: Goal is to test KPiX acquisition in ILC-like conditions, verify output normalization
We now have high-
precision measurements
of silicon positions:
can perform 3-d tracking
and reconstruct vertical
beam profile

44. ESTB Stage II Hadron Production
Add Be target, beam dump, analyzing magnet, momentum slit, and quadrupole doublets to produce a secondary hadron beam in ESA
Production angle = 1.35O and Acceptance = 10 sr
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

45. Secondary Hadron Beam Properties
Beam Properties at Detector Plane
x=1mm
y=1.4mm
E/E=1.3%
Energy –12 GeV
Particles per pulse –10 / nC
Bunch repetition rate 5 Hz
Precise beam trigger Yes
rms x, y spot size mm
Momentum analysis p/p ~ 1%
x,y,z space available 5 m, 5 m, 15 m
Rate for p, K,  /
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

46. First beam early summer 2011
ESTB Status
New BSY kicker magnets, power supply and vacuum chambers
All items are in the design stage (based on existing hardware)
Will be installed during the down March/April 2011
New small beam dump for ESA
Design is clear
Radiation protection calculations are ongoing
Will be installed early 2011
New Personnel Protection System (PPS)
Is the most complicated of the needed upgrades
Design has started and implementation plan is under development
My hope is to get it done until early 2011
We are planning on a User Workshop in conjunction with another meeting late this year or early 2011
First beam early summer 2011
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department

47. ESTB Time Line for Hadrons
Funding will be made available after we have had beam in ESA
June2011 primary beam to ESA
 Additional funds may be released…
Need about 4-6 month to design and build hadron target and auxiliary infrastructure, new magnet stands, beam pipe
About 2 month to install equipment in ESA
During short winter shutdown 2011/2012 install target in A-line
Hadron Beam to ESA Winter 2011/12
Carsten Hast - ARD Test Facilities Department

48. Need electron beam? Come to SLAC!
Conclusions
2011 will be an exciting year at SLAC
LCLS and SPEAR continue marvelous things
FACET and ESTB coming on line
But hurry LCLS II is getting ready to take over the Linac
NLCTA and possibly ASTA upgrades
Very long term plans are in the making
Need electron beam? Come to SLAC!
SLAC User Facilities
Carsten Hast - ARD Test Facilities Department