FEE Commissioning

1 Hal [email protected]

1FEE CommissioningJune 09 FAC

FEE Commissioning

Hal Tompkins – Photon Beam Systems DeputyJune 8, 2009



Beam Schedule

First beam into FEE late June/early July

First beam into NEH late July

First scheduled user run Sep-Dec.

CD 4 goal of beam to FEH accomplished March, 2010



FEE Layout

Gas Detectors

Gas Attenuator

Direct Imager(Scintillator) FEL Offset Mirror Systems

Beam Direction

SolidAttenuators

K-Mono

Thermal Sensor

Slit

5 mm collimator



Interim FEE Layout



Phase 1 CommissioningCommissioning time must be shared between electron and photon halvesReliable lasing at all wavelengths has already been demonstrated

B4C testing is part of commissioningDeposited power is greatest at 830 eV operation - estimated dose to B4C at ST1 is .35 eV/atom, melt dose is calculated at .63 eV/atom

B4C testing in ST0 chamber took place in May - this location is 48 m from end of undulator

B4C target is continuously monitored with camera at MCC for damage - log entries required on daily basis



Phase 1 Commissioning

Ref.

Cen.



Phase 1 commissioning (cont.)

Requirements for allowing beam to FEE:FEE included in expanded SAD/ASE which is being reviewed internally at SLAC

Accelerator Systems Division (ASD) responsible for operation of FEE

FEE PPS certified

RP survey plan based on LCLS commissioning plan

Beam Authorization Sheet for FEE



Phase 1 Commissioning (cont.)

Requirements for allowing beam to FEE (cont.):B4C “moveable mask” installed upstream of FEE stoppers (ST1 and ST2)Direct Imager YAG screen permanently installed in beam pathC1 Collimator installed in planned location

Temporary beam dump (B4C and W alloy) installed on differential pump standTwo protection ion chambers (PIC’s) downstream of C1 and two more downstream of temporary dumpAir gap of 20 cmThree pairs of hutch stoppers with BTM’s active and stoppers locked closed installed in planned locationC3 collimators installed in planned locationShadow wall and wall 2 window installed




Installation in downstream half of FEE can proceed during day shift, in parallel with B4C testing in ST0 canDiagnostics and FEL commissioning can proceed during swing and owl shiftsASD will have to search and secure the FEE every dayUpstream half of FEE will require RSWCF for breaking vacuumDamage to Direct Imager YAG screen requires immediate inspection of C1 and temporary beam dumpTarget date for beam to FEE is late June/early July

C1, C3 collimatorsFEE PPS




Overall diagnostics commissioning plan has needed revision - nobody expected immediate lasing at 1.5 Ang.Diagnostics commissioning still begins with Direct Imager - want spontaneous radiation

Open FEE stoppers - follow RP survey planBegin with adjustable slits closed

B4C apertures in attenuator rafts openSlowly open adjustable slits - verify proper slit operationVerify 25 mm x 45 mm fixed mask apertureInsert B4C apertures singly, then each raft.Raft alignment best done with FEL - be careful to keep YAG below saturation



As seen in Direct Imager, using 5 µm YAG

Soft X-ray spontaneous from full undulator (calculated)



Hard X-ray spontaneous, from full undulator (calculated)




Soft X-ray FEL signal in Direct Imager

Peak pixel has 160 photoelectrons / nJ of FEL





Commission gas detectors - use FELAdd nitrogen gas to detector volumePower magnetCompare APD & PMT response to changes in intensityRepeat at several different photon energies/gas pressures

Commission gas attenuator - interleaved with gas detector commissioningCommission K-monochromator

Transmit beam through 4 bounces (~8.172 eV)Check out quadrant photodiodeConfirm Ni foil calibration of linac energy




Commission Total Energy detectorPulse energy already measured to be ~1-2 mJ by electron side with ~50% error barsThis measurement is good enough to claim CD 4 goal of 106 photons/mm2-0.1%BW-pulse (though technically it was not made in the FEE)TEM should be accurate to 5-10%

Pulse energy measurement is crucial for B4C testing confidence

Once total energy monitor is commissioned, cross-calibrate the gas detectors and the direct imager

This needs to be done at multiple energies - emphasis on the 830-1800 eV rangeIt also needs to be done at multiple intensities - but we must protect the YAG



Phase 2 Commissioning

Beam to downstream half of FEEVery useful for commissioning pop-in monitors and offset mirror systems - can commission through P3’s

Will require agreement from RSO that B4C test piece in ST0 can has seen sufficient number of FEL pulses to justify confidence in B4C being “FEL-proof”

Some fraction of commissioning time will continue to be spent dumping pulses into ST0 test mask

FEL will terminate at hutch stoppers S1, S2, and SH1 or B4C-protected collimators



HOMS and SOMS mounts share a common design

With temperature controlled to 0.01

deg, pointing stability is better

than 10 nrad

OMS



LCLS Offset Mirror Systems

HOMS: Hard x-ray Offset Mirror System

SOMS: Soft x-ray Offset Mirror System

830-2000 eV to Hutch 1

830-2000 eV to Hutch 2



NEH Commissioning

NEH beam stepsNEH ARR June 30-July 1

AMO IRR mid-July

Hutch HPS certified

XFD Operations procedures in place, reviewed, and approved by SLAC

24/7 floor coordinator coverage in place

Beam Line Authorization for Hutch 1

AMO beam containment plan approved by RSO

Beam to NEH in late July



Summary

First beam into FEE late June/early July

First beam into NEH in late July

First scheduled user run Sep-Dec

CD 4 goal of beam to FEH March, 2010

FEE Commissioning

Documents

Transcript of FEE Commissioning