SLAC has long encouraged and supported Research and Development in High Energy Physics

SLAC Test BeamsSLAC Test Beams

SLAC has long encouraged and supported Research and Development in High Energy Physicsthrough an active program of providing beams for the purpose of testing detector prototypesor for use in small experiments.

Use of SLAC’s test beams is open to all in the scientific communityand proposals for their use are actively invited.

Through the clever use of parasitic beams, many such tests or small experimentshave been successfully carried out during periods when the linac is dedicated toproviding beam for others.

These parasitic beams of electrons are available in the Final Focus Test Beam tunneland in End Station A.

SLAC provides beam time, mechanical support, technical support, computer and network Access.

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SABER

ESA

Pulsed Magnets

LCLS

Linac

FFTB

BSY



How a Parasitic Beam is produced



Tagged Photons



Test Beams in ESA

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Test Beams in ESA

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Test Beams in FFTB

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LinacLocation of Hadron Target

and Pulse Magnets

Linac Movable CollimatorsLCLS Halo Collimators

L. Keller, using EGS, has estimated a yield of 8 electrons per pC-pulse

At 2.25 GeV into A-line acceptance from the halo of 13 GeV LCLS beam

Hitting a 9mm Tungsten Target

Can we obtain a pC of halo hits from Dark Current and Gas Scattering?

Parasite beam from LCLS?

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SLAC Test BeamsSLAC Test BeamsStructure dark currentStructure dark current

Contribution of structure dark current:Contribution of structure dark current:• X-bandX-band gives the largest contribution, however, deflected gives the largest contribution, however, deflected• Structures withStructures with E~24 MV/mE~24 MV/m will give additional particle loss will give additional particle loss

Green: difference

Black: total

Red: Gun DC only

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Tracking and Collimation, by Juhao Wu, Tracking and Collimation, by Juhao Wu, LCLSLCLS

undulatorundulator

‘‘L0-b’L0-b’startstart

existing existing collimatorscollimators

(4 (4 xx and 4 and 4 yy))

new new energy energy

collimatorscollimators

new new collimatorscollimatorsBC1 coll.BC1 coll. BC2 coll.BC2 coll.

‘‘underunderground’ground’

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SLAC Test BeamsSLAC Test Beams2-Phase, 2-Plane Und. Collimation, 1½ Times2-Phase, 2-Plane Und. Collimation, 1½ Times

xx11 xx22 xx33

phase-1phase-1 phase-2phase-2 phase-1 phase-1 againagain

halohalo

7070((2.5 mm)2.5 mm)4040

((2.2 mm)2.2 mm)

undulator undulator beam pipebeam pipe

4545

edge edge scatteringscattering

(also collimation in (also collimation in yy and energy – see next slides) and energy – see next slides)

ee beam beam

4040((2.2 mm)2.2 mm)

By Juhao Wu,

LCLS

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Collimation in Linac-To-Undulator (LTU)Collimation in Linac-To-Undulator (LTU)EE11 EE22

yy11

xx22

yy22

xx33

yy33

muon muon shieldingshielding

undulatorundulator

xx11

--spoilerspoiler

By Juhao Wu,

LCLS

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SLAC Test BeamsSLAC Test BeamsParticle losses up to, and through BC1Particle losses up to, and through BC1

BC1BC1DL1DL1L0-bL0-b L1L1X-bandX-band

1-inch ID1-inch ID 7-mm ID7-mm ID

120 pC lost per pulse120 pC lost per pulse= 1.9 W @ 120 Hz, 135 MeV= 1.9 W @ 120 Hz, 135 MeV

300 pC lost per pulse300 pC lost per pulse= 9 W @ 120 Hz, 250 MeV= 9 W @ 120 Hz, 250 MeV

= 30

By Juhao Wu,

LCLS

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Particle losses through undulator and dumpParticle losses through undulator and dump

BC2BC2 undulatorundulator

2.6 pC/pulse2.6 pC/pulse3.5 W (120 Hz,3.5 W (120 Hz,

11.3 GeV)11.3 GeV)

4 4 existingexisting xx-coll.’s-coll.’s4 4 existingexisting yy-coll.’s-coll.’s1.6 & 1.6 & 1.8 mm1.8 mm

2 2 newnew EE-coll-coll..22..5 mm (5 mm ( = = 2%)2%)

3 3 newnew xx-coll.’s-coll.’s3 3 newnew yy-coll.’s-coll.’s2.2 mm…2.2 mm…

1 1 newnew BC2BC2 EE-coll-coll..36-mm (36-mm ( = = 10%)10%)

1 1 newnew BC1BC1 EE-coll-coll..45-mm (45-mm ( = = 20%)20%)

0.1 pC/pulse0.1 pC/pulse0.2 W (120 Hz,0.2 W (120 Hz,13.6 GeV)13.6 GeV)

BC1BC1

0.7 pC/pulse0.7 pC/pulse1.1 W (120 Hz,1.1 W (120 Hz,

13.6 GeV)13.6 GeV)

underundergroundground

EE//EE of 1 dropped klystron = of 1 dropped klystron = 1.7%1.7%

By Juhao Wu,

LCLS

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• Advantage--High energy high current beam from present CID guns

• Up to ~45 GeV, 6x1011 e-/pulse 120Hz,• Damping Rings optional• Not LCLS Compatible, switchover not fast• Secondary beams (hadron) could also be available, but

inefficient use of machine• LCLS promised 75% of operating time, problematic future

for this option

Options for test beam with LCLS

1.Independent intermittent operation

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• At beginning LCLS will operate at 5 GeV. The existing pulse magnets can handle 10 GeV.

• Beam Limited to LCLS parameters, ~5GeV < 109 electrons/pulse, ~10Hz

• Two more Pulse Magnets exist but must be refurbished and two Power Supplies provided, ~$200k Allow operation at LCLS design energy of ~14 GeV

• Could also switch beam to SABER but low current not too useful. Plasma Acceleration needs high charge, short pulse. SPPS type use may be possible. (?)


2. Share LCLS beam using pulse magnets

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• A feasiblity study SABER in BTR is ongoing. A bypass line has been shown to be optically possible. Transactions PAC05, P. Emma, et. al. “Proposal for a Multi-Use Test Beam in the SLAC B-line

• Would provide beam suitable for Plasma Acceleration, SPPS type fast Xrays, Final Focus studies (A. Seryi)

• Expensive• The present design for a bypass to BTR is assymetric. It

is not known if it would accommodate beam to ESA. Perhaps a wholly different beam line design is necessary.

• Problematic


3. Bypass Lines around LCLS

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• Would be available on call.• Suitable for some detector tests but not for ILC

instrumentation.• Not a proven concept, needs much more work.• Problematic


4. Beams Parasitic to LCLS

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• All these options are being looked at• Assistance or other Suggestions welcomed• Input concerning the usefulness of each is helpful


4. Beams Parasitic to LCLS

3. Bypass Lines around LCLS

2. Share LCLS beam using pulse magnets

1.Independent intermittent operation

SLAC has long encouraged and supported Research and Development in High Energy Physics

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