Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC,...

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Linac Beams for Linac Beams for Fixed Target Fixed Target Experiments Experiments Presentation by Roger Erickson Presentation by Roger Erickson SLAC Operations Review SLAC Operations Review SLAC, June 15-16, 2004 SLAC, June 15-16, 2004
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Page 1: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

Linac Beams for Linac Beams for Fixed Target ExperimentsFixed Target Experiments

Presentation by Roger EricksonPresentation by Roger Erickson

SLAC Operations ReviewSLAC Operations ReviewSLAC, June 15-16, 2004SLAC, June 15-16, 2004

Page 2: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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OutlineOutline

Linac and sourcesLinac and sources Interleaved beamsInterleaved beams A-Line and End Station A (ESA)A-Line and End Station A (ESA) Final Focus Test Beam (FFTB)Final Focus Test Beam (FFTB) Secondary Test BeamsSecondary Test Beams SummarySummary

Page 3: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Linac Beam LinesLinac Beam Lines

LCLS will add an electron injector downstream of the positron source.

Fixed target experiments can be carried out in End Station A (ESA) or the Final Focus Test Beam (FFTB) facility.

Page 4: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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The Two-mile LinacThe Two-mile Linac

50 GeV Linac with multiple pulsed extraction points.50 GeV Linac with multiple pulsed extraction points. 120 pulses per second max; now running 30.120 pulses per second max; now running 30. Up to 6e11 electrons per pulse.Up to 6e11 electrons per pulse. Polarized electrons available up to full intensity.Polarized electrons available up to full intensity. 4e10 positrons per pulse, interleaved with electron 4e10 positrons per pulse, interleaved with electron

pulses.pulses. Long pulses (undamped) or short pulses (damped).Long pulses (undamped) or short pulses (damped). Typically running two programs simultaneously:Typically running two programs simultaneously:

• PEP-II• Fixed target in ESA or FFTB

Flexibility for interleaved beams: e+, e-, damped and Flexibility for interleaved beams: e+, e-, damped and undamped, different energies, intensities and rates.undamped, different energies, intensities and rates.

Page 5: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Typical (Recent) Running ModeTypical (Recent) Running Mode

Linac runs well at 30 pulses/sec (half the ac line frequency).Linac runs well at 30 pulses/sec (half the ac line frequency).

9 GeV electrons to HER: on demand for trickling, up to 10 Hz.9 GeV electrons to HER: on demand for trickling, up to 10 Hz. 3.1 GeV positrons to LER: on demand for trickling, up to 10 Hz.3.1 GeV positrons to LER: on demand for trickling, up to 10 Hz. 28.5 GeV “scavenger” electrons to Sector 19 28.5 GeV “scavenger” electrons to Sector 19

(to make more positrons for the next cycle).(to make more positrons for the next cycle). 28.5 GeV electrons to FFTB: 10 Hz for fixed target programs28.5 GeV electrons to FFTB: 10 Hz for fixed target programs

(interleaved with PEP injection pulses).(interleaved with PEP injection pulses).

At the push of a button,At the push of a button, Electrons and Positrons to PEP-II for rapid filling at 15 Hz each Electrons and Positrons to PEP-II for rapid filling at 15 Hz each

(with no rate to FFTB).(with no rate to FFTB).

Page 6: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Research Yard Experimental FacilitiesResearch Yard Experimental Facilities

ESA

FFTB

Page 7: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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A-Line to ESAA-Line to ESA

SLAC’s original experimental hall, site of parton discovery and SLAC’s original experimental hall, site of parton discovery and parity violation in eP scattering.parity violation in eP scattering.

Recent E-158 success: first observation of parity violation in Recent E-158 success: first observation of parity violation in polarized e-e- Moller scattering. polarized e-e- Moller scattering. E-158 had three production runs at 120 Hz in 2002-2003; E-158 had three production runs at 120 Hz in 2002-2003; once with PEP-II and twice alone.once with PEP-II and twice alone.

High power (500 kW) beam capability.High power (500 kW) beam capability. ESA is convenient for staging fixed target experimentsESA is convenient for staging fixed target experiments

• Large, massively shielded building.• Power, LCW, and cryogenic facilities.• Easy truck access.• Crane coverage.• Counting house with DAQ facilities.

Strong bends and weak focusing preclude “FFTB beams” with Strong bends and weak focusing preclude “FFTB beams” with small emittance and compressed bunch length.small emittance and compressed bunch length.

Page 8: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Energy dithering region

BPM ~2 microns

energy ~1 MeV

Agreement (MeV)

BPM

24

X (

MeV

)

BPM12 X (MeV)

toroid ~30 ppm

A-Line Beam Monitoring DevicesA-Line Beam Monitoring Devices

Page 9: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Parameter E-158 NLC-500

Charge/Train 5 x 1011 14.4 x 1011

Repetition Rate 120 Hz 120 Hz

Energy 45 GeV 250 GeV

e- Polarization 85% 85%

Train Length 270ns 267ns

Microbunch spacing 0.3ns 1.4ns

Beam Loading 13% 22%

Energy Spread 0.15% 0.16%

E-158 BeamE-158 Beam

Comparison with 500 GeV Linear Collider Design.

Page 10: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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End Station AEnd Station A

Photo Shows E-158 Spectrometer Magnets.

Page 11: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Pending Programs in ESAPending Programs in ESA

Calibration of GLAST detector components Calibration of GLAST detector components

with secondary hadrons with secondary hadrons

(to be scheduled to accommodate GLAST requirements).(to be scheduled to accommodate GLAST requirements).

A Letter of Intent submitted to the EPAC:A Letter of Intent submitted to the EPAC:

Beam Instrumentation Tests for the Linear Collider Beam Instrumentation Tests for the Linear Collider

using the SLAC A-Line and End Station Ausing the SLAC A-Line and End Station A

Page 12: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Final Focus Test BeamFinal Focus Test Beam

The FFTB was originally built to demonstrate technology for The FFTB was originally built to demonstrate technology for focusing and measuring sub-micron electron beams suitable for a focusing and measuring sub-micron electron beams suitable for a future linear collider.future linear collider.

Recent on-going programs include:Recent on-going programs include:

Plasma Wakefield Acceleration – a series of experiments that have Plasma Wakefield Acceleration – a series of experiments that have recently demonstrated high-gradient acceleration in a lithium recently demonstrated high-gradient acceleration in a lithium plasma.plasma.

SPPS – A new facility that uses compressed electron bunches to SPPS – A new facility that uses compressed electron bunches to generate intense x-ray pulses.generate intense x-ray pulses.Technology applicable to the LCLS:Technology applicable to the LCLS: Extreme bunch compression. Beam control and feedback for stability. Instrumentation for characterizing extremely short x-ray pulses.

Page 13: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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FFTB Experimental AreaFFTB Experimental Area

Page 14: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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RTL

DAMPINGRING

SLAC LINAC

9 ps 0.4 ps

50 ps

1 GeV 28.5 GeV

14-meter chicane compressor in linac at 1/3 point (9 GeV)

CHICANEBENDINGMAGNETS

LONGER PATHTAKEN BY HEAD OF THE BUNCH

Energy

e-

Energy

Time

ELECTRON BUNCH WITH HIGHER ENERGY TAIL

TAIL BEGINS TO CATCH UP

FULLY COMPRESSED

FFTB

Short Bunches in FFTB

Page 15: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Plasma Wakefield Acceleration Plasma Wakefield Acceleration

e-

N=1.81010

z=20-12µmE=28.5 GeV

Optical TransitionRadiators

Li Plasma Gas Cell: H2, Xe, NO

ne≈0-1018 cm-3

L≈2.5-20 cm

Plasma light

X-RayDiagnostic,

e-/e+

Production

CherenkovRadiator Dump

∫Cdt

ImagingSpectrometer

EnergySpectrum“X-ray”

25m

CoherentTransition

Radiation andInterferometer

0 +5-5

ne=2.5x1017No Plasma

Gain

Loss

0 +5-5

7.9

GeV

≈3 GeV!

ne=2.5x1017

0 +5-5

Pyro=484

0 +5-5

+1.5 GeV

ne=3.5x1017No Plasma

Min.Gain

Min.Loss

0 +5-5

Rel

ativ

e E

nerg

y (G

eV)

Page 16: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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SPPS in FFTBSPPS in FFTB

Page 17: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Photon beam line

Electron beam line

Experimental Area

Beamdump

FFTB Dump Line Experimental Area

Page 18: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Pending Programs in FFTBPending Programs in FFTB

SPPSSPPSOngoing program of technology development involving extremely short x-Ongoing program of technology development involving extremely short x-ray pulses.ray pulses.

Plasma Wakefield AccelerationPlasma Wakefield AccelerationOngoing program to develop exotic new methods for achieving very high Ongoing program to develop exotic new methods for achieving very high accelerating gradients, strong plasma focusing, and related technology.accelerating gradients, strong plasma focusing, and related technology.

Experiment E-165Experiment E-165Flourescence in Air from Showers (FLASH)Flourescence in Air from Showers (FLASH)

A continuing program to quantitatively understand the production of light A continuing program to quantitatively understand the production of light by cosmic rays in the upper amosphere, using controlled laboratory by cosmic rays in the upper amosphere, using controlled laboratory conditions.conditions.

Experiment E166Experiment E166 A Proposal to Test Production of Polarized Positrons with the SLAC 50-GeV A Proposal to Test Production of Polarized Positrons with the SLAC 50-GeV Beam in the FFTBBeam in the FFTBAn undulator-based technique applicable to a future linear collider.An undulator-based technique applicable to a future linear collider.

Page 19: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Test Beam FacilitiesTest Beam Facilities

Primary electron or positron beams to ESA or FFTB.Primary electron or positron beams to ESA or FFTB.

Secondary electron or positron beams to ESA or FFTB.Secondary electron or positron beams to ESA or FFTB.• Produced by double conversion (e- to gammas to e+ or e-).• One or a few particles/pulse.• Energy easily selectable with transport line magnets.

Secondary hadron beam to ESA.Secondary hadron beam to ESA.• Primary electrons to beryllium target near end of linac.• Secondary particles scattered at 0.5 deg into A-Line.• Positrons, pions, kaons, and protons tagged with time-of-flight and

Cerenkov detectors. One tagged particle/pulse was delivered to GLAST detector development test.

Page 20: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Test Beam SchedulingTest Beam Scheduling

The approval and scheduling process is designed to minimize effort for outside The approval and scheduling process is designed to minimize effort for outside users and minimize cost and impact for SLAC.users and minimize cost and impact for SLAC.

Proposals are submitted to Experimental Facilities Department. EFD staff Proposals are submitted to Experimental Facilities Department. EFD staff provide technical and administrative support for users.provide technical and administrative support for users.

““Test Request” summary is circulated to:Test Request” summary is circulated to:• Radiation physicist• Chairman, Safety Oversight Committee• FFTB (or ESA) Area Manager• Accelerator Department physicist• Research Division Program Coordinator

Test Request is submitted to Accelerator Department Operations Section for Test Request is submitted to Accelerator Department Operations Section for scheduling.scheduling.

Beam Authorization Sheet is prepared by Radiation Physics Department.Beam Authorization Sheet is prepared by Radiation Physics Department.

Most test beam experiments are carried out with no significant adverse impact Most test beam experiments are carried out with no significant adverse impact on other programs. Many are done in 1 to 3 days.on other programs. Many are done in 1 to 3 days.

Page 21: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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Test Beam Experiments in FFTBTest Beam Experiments in FFTB

T-447T-447 Single Pulse Damage in Materials (Sept 2000)Single Pulse Damage in Materials (Sept 2000)T-448T-448 Magnified Optical Transition Radiation Test (Oct 2000)Magnified Optical Transition Radiation Test (Oct 2000)T-450T-450 Damage Test in Diamond for LCLS (Oct 2000)Damage Test in Diamond for LCLS (Oct 2000)T-451T-451 High Energy Neutron Spectra Measurement (March 2001)High Energy Neutron Spectra Measurement (March 2001)T-452T-452 STAR Endcap Calorimeter Detector Prototype Test (Jan 2001)STAR Endcap Calorimeter Detector Prototype Test (Jan 2001)T-453T-453 Radiation Damage in Diamond for LCLS (April 2001)Radiation Damage in Diamond for LCLS (April 2001)T-454T-454 Measurement of Neutron Spectra (June 2001)Measurement of Neutron Spectra (June 2001)T-455T-455 Measurement of the Calorimeter for the Local Polarimeter at Phenix/RHIC (Aug 2001)Measurement of the Calorimeter for the Local Polarimeter at Phenix/RHIC (Aug 2001)T-456T-456 Magnetization Dynamics in Magnetic Films (Sept 2001)Magnetization Dynamics in Magnetic Films (Sept 2001)T-457T-457 Measurement of Neutron Energy Spectra Using Bonner Multi-Sphere Spectrometer (June Measurement of Neutron Energy Spectra Using Bonner Multi-Sphere Spectrometer (June

2002)2002)T-460T-460 Characterization of Askaryan Effect in Rock Salt (June 2002)Characterization of Askaryan Effect in Rock Salt (June 2002)T-461 T-461 High Atmosphere Air Fluorescence (June 2002)High Atmosphere Air Fluorescence (June 2002)T-462 T-462 Magnetization Dynamics of Soft-Magnetic Films (June 2002)Magnetization Dynamics of Soft-Magnetic Films (June 2002)T-464 T-464 Correlation of Linac Transverse Deflection Cavity with FFTB Streak Camera (June 2002)Correlation of Linac Transverse Deflection Cavity with FFTB Streak Camera (June 2002)T-465 T-465 Magnetization Dynamics in the Sub-picosecond Time Scale (May 2003)Magnetization Dynamics in the Sub-picosecond Time Scale (May 2003)T-466 T-466 UCLA Electromagnetic Calorimeter (EMC) Prototype (May 2003)UCLA Electromagnetic Calorimeter (EMC) Prototype (May 2003)T-467T-467 Measurement of FFTB Backgrounds for E166 (Jan 2004)Measurement of FFTB Backgrounds for E166 (Jan 2004)T-468T-468 Diamond Detector Response (July 2003)Diamond Detector Response (July 2003)

Experiments not yet run:Experiments not yet run:T-469T-469 DIRC R&D ProgramDIRC R&D ProgramT-470T-470 DASH: Diamond Detectors for FLASHDASH: Diamond Detectors for FLASHT-471T-471 Incoherent Radio Emission from ShowersIncoherent Radio Emission from Showers

Page 22: Linac Beams for Fixed Target Experiments Presentation by Roger Erickson SLAC Operations Review SLAC, June 15-16, 2004.

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ConclusionsConclusions

Extra linac pulses, not needed for PEP-II injection, can be delivered to End Extra linac pulses, not needed for PEP-II injection, can be delivered to End Station A or the FFTB facility for use by fixed target or “test beam” Station A or the FFTB facility for use by fixed target or “test beam” experiments.experiments.

We have seen a constant demand for these beams from a wide variety of We have seen a constant demand for these beams from a wide variety of users.users.

Small experiments can be set up and run with no adverse impact on the Small experiments can be set up and run with no adverse impact on the PEP-II program and with very little additional cost to SLAC.PEP-II program and with very little additional cost to SLAC.

Significant new physics results have been achieved, and a large number of Significant new physics results have been achieved, and a large number of detector technology development tests have been carried out.detector technology development tests have been carried out.

The FFTB will be dismantled in 2006 to make room for the Linac Coherent The FFTB will be dismantled in 2006 to make room for the Linac Coherent Light Source (LCLS). We are exploring possible replacement options.Light Source (LCLS). We are exploring possible replacement options.

The requests for test beams keep coming!The requests for test beams keep coming!