1

Plan and Opportunities for Migration and Plan and Opportunities for Migration and Integration of the Photoinjector into New Integration of the Photoinjector into New

Muon LabMuon Lab

Mike Church

AAC Review - 12/5/06

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

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Current Photoinjector Layout at A0Current Photoinjector Layout at A0

P. Piot

(CC-1)

13m

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

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Proposed NML Injector Layout Proposed NML Injector Layout (latest design)(latest design)

P. Piot

(CC-1, CC-2)

(intended initially for ILC crab cavity tests)

22m

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

4

NML Building Layout NML Building Layout (front end)(front end)

egun 3rd cryomodule(if no building extension)

u.s end of 1st cryomodule

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

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Tentative ScheduleTentative Schedule

• Photoinjector operations will continue at A0 through CY07

• The move of the A0 photoinjector will be delayed until 1/08 so that T. Koeth’s thesis experiment can be completed

• Upgrades that are planned at A0 before moving to NML include the following

• laser: upgrade 2-pass and multipass flash lamp pumped cavities to diode laser pumped cavities

• addition of downstream off-axis beamline for emittance exchange experiment (T. Koeth’s thesis)

• New egun and modulator will be developed

• A0 gun suffers E-field breakdown in RF-coupling slot for pulse lengths >300 sec

• Modulator needs upgrade to operate at 5 Hz and 1msec pulse length

• 2nd TESLA cavity (CC-2) is being conditioned at Meson Detector Building

• 3rd harmonic cavity: will not be ready in early CY08

• We estimate the move can be accomplished in ~4 months (not including beam commissioning)

• We expect egun, modulators, and CC-2 to be ready for installation in early CY08

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

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PITZ Egun PITZ Egun (Photo Injector Test Facility at DESY Zeuthen)(Photo Injector Test Facility at DESY Zeuthen)

1 ½ cell RF cavity (1.3 GHz)

RF coaxial feed

photocathode

laser mirror

Capable of delivering ILC beam parameters, with normalized transverse emittance ~4E-6

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

7

Photoinjector Upgrades for NMLPhotoinjector Upgrades for NML

• Laser - no additional major upgrades for NML

• Egun – entirely new – similar to PITZ egun design; capable of ILC beam parameters

• Egun modulator – upgrade: 1 Hz 5 Hz; 300 sec 1 msec

• Beamline – higher energy decreased dp/p

• 3rd harmonic cavity – shorter bunch length; higher peak current

• Instrumentation – (possibly) new BPM’s

• Off-axis beamline – addition of a 4-dipole dogleg will provide an off-axis beamline for testing ILC crab cavities, emittance exchange experiment, and other tests

• Better integrated controls system –

• Increased experimental areas – see P. Piot’s talk

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

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Downstream Beamlines at NMLDownstream Beamlines at NML

spectrometer magnet (dE/E ~1E-4) high energy

test area low power dump

high power dump (34KW)

diagnostic section

No room to slide cryomodules downstream!

beam spot size required to be >3mm

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

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Photoinjector Design for 3 Cryomodules and No Building ExtensionPhotoinjector Design for 3 Cryomodules and No Building Extension

Egun

Capture Cavity

(1.3GHz) quads

low energy spectrometer

chicane (for bunch compression) 1

st cryomod

ule

9.9 meters

X X X X

X

quadsdipole corr.

dipole corr.

BPM pair

instrumentation cross

current monitor

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

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Bunch Compression Bunch Compression (22.5(22.5° chicane)° chicane)

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

-0.0050 -0.0025 0.0000 0.0025 0.0050

dp

/p

dz [m]

-0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

-0.0015 -0.0010 -0.0005 0.0000 0.0005d

p/p

dz [m]

After Chicane:

RMS bunch length =.34 mm

Before Chicane:

RMS bunch length =2.40 mm

Egun: Peak acc. gradient=20MV/m, phase=-10°CC-1: Peak acc. gradient=16MV/m, phase=-37.5°

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

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Comments on Reduced PhotoinjectorComments on Reduced Photoinjector

• Limitations:

• No space for 3rd harmonic cavity – “banana” shape in longitudinal phase space – how does one interpret cavity measurements under these conditions? Can’t quite get 300 micron bunch length.

• off-axis beamline does not have tuneable R56 (as in the full photoinjector design) – not suitable for ILC crab cavity testing

• large momentum spread – very difficult to control beam size (maybe impossible)

• Low energy (KE=18.2 MeV) – space charge may additionally blow up beam

• No room for additional experiments

• Minimal space for instrumentation and correctors – not sure we have enough

• No flat beam transform

• CC-1 not suitable (can only get peak acc. gradient=12MV/m); must use CC-2

Migration of Photoinjector to NMLAAC Review 12/5/06 – M. Church

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OutlookOutlook

• Moving the photoinjector from A0 to NML will provide opportunities for upgrades to permit full beam testing of 1-2 ILC cryomodules

• The new photoinjector will provide opportunities to fully test ILC crab cavities

• However, the space constraints put on the photoinjector after the addition of the 3rd cryomodule without a building extension make the photoinjector unsuitable for full beam testing of ILC cryomodules or crab cavities