Download ppt - 1 Heinz-Dieter Nuhn [email protected] 1 Undulator Plans June 2009 FAC Undulator Commissioning Heinz-Dieter Nuhn – LCLS Undulator Group Leader June

1 Heinz-Dieter [email protected]

1Undulator PlansJune 2009 FAC

Undulator Commissioning

Heinz-Dieter Nuhn – LCLS Undulator Group LeaderJune 8, 2009



29 Undulators Installed



Segment Installation Schedule

Undulator Segments are being installed in the tunnel as they finish tuning

1/25/2009 – 3/2/2009 (U25 (SN16) Test installation)

3/3-24/2009 U13 – U33

4/22/2009 U09 – U12

5/13/2009 U06 – U08

6/3/2009 U04 and U05

6/3/2009 Removed U33 for damage check.

6/17/2009 U02, U03, and U33 installation planned.

Three plus one more undulators are to be installed

Regular Undulator Rotation Program will start after temperature calibration procedure

Undulator Segments are being installed in the tunnel as they finish tuning

1/25/2009 – 3/2/2009 (U25 (SN16) Test installation)

3/3-24/2009 U13 – U33

4/22/2009 U09 – U12

5/13/2009 U06 – U08

6/3/2009 U04 and U05

6/3/2009 Removed U33 for damage check.

6/17/2009 U02, U03, and U33 installation planned.

Three plus one more undulators are to be installed

Regular Undulator Rotation Program will start after temperature calibration procedure



Undulator Beam Operation Highlights

December 13, 2008 First electron beam through undulator vacuum chamber.

No extra steering corrections necessary to get 100% transmission to main dump.

Pre-beam girder alignment was sufficient.

April 10, 2009 First electron beam through undulator segments.

Detected FEL beam after 105 minutes, CCD saturation 20 minutes later.

December 13, 2008 First electron beam through undulator vacuum chamber.

No extra steering corrections necessary to get 100% transmission to main dump.

Pre-beam girder alignment was sufficient.

April 10, 2009 First electron beam through undulator segments.

Detected FEL beam after 105 minutes, CCD saturation 20 minutes later.



Preset Girder Positions for First Beam

• The girders were moved in x and y direction before the first beam was sent through the undulator, mostly to align the beam pipes and the quadrupoles as close to a straight line as possible but also to use the off-axis quadrupole fields to compensate for the earth magnetic field. Both corrections were based on measurements provided by the Metrology group.

• The first beam shot did not need any alignment correction to pass through the undulator beam pipe (remember a 130-m-long soda straw) to the main dump. The maximum orbit error was only about 1 mm. The plot is from J. Welch's girderPositionPlotGui and shows schematically the position by which each of the girders was displaced.



Checking Undulator K Using YAG Luminescence*

10 or 11 undulators IN, Ipk = 500 A, LH = 200 uJFirst and third harmonic of spontaneous radiation as background

3rd hamrmonic ofSpontaneous

UndulatorRadiation on YAG

Crystal

Ee = 11.1 GeV

Ee = 11.3 GeV

Ee = 11.5 GeV

Ee = 11.7 GeV

Ee = 11.9 GeV

SpontaneousRadiation from

Dump Bend

Yttrium K Edge at 17.038 keVequals 3rd harmonic of undulator

radiation at 11.286 GeV

*by J. Welch and J. Frisch

Kmax =3.4256

Kmin =3.3532

Kavg =3.4616

Expected Kund = 3.4926±0.0005

More precise bracketing gave Kavg =3.4932±0.0045 (1.7 ×10-4 from expected value)



YAG Screen Image of First Lasing

10 or 11 undulators IN, Ipk = 500 A, LH = 200 uJFirst and third harmonic of spontaneous radiation as background

FIRST LCLS FEL

LIGHT



Undulator Characterization: 1st Field Integral U09

Beam Based Measurements

Horizontal (I1X) and vertical (I1Y) first field integrals measured by fitting a kick to the difference trajectory as function of undulator displacement

Reference Point

MMF Measurement



Measurement of 1st Field Integral U11

Beam Based Measurements

Reference Point

MMF Measurement

The beam-based measurement relies on the RF cavity BPMS to achieve a 20 nrad measurement resolution of the kick angle inside the undulator



Alignment Tolerance Verification

Random misalignment with flat distribution of widh ±a => rms distribution a/sqrt(3)



Simulated: Horizontal Module Offset

Horizontal Model Offset (Gauss Fit)

Location Fit rms Unit

090 m 0782 µm

130 m 1121 µm

Average 0952 µm

Simulation and fit results of Horizontal Module Offset analysis. The larger amplitude data occur at the 130-m-point, the smaller amplitude data at the 90-m-point.

S. Reiche Simulations 2006S. Reiche Simulations 2006

BudgetTolerance

90 m

130 m

Simulated Saturation occurred at 90 m

Actual Simulation occurred at 68 m

Correction factor sqrt (90/68) = 1.15

This brings average to 1.10 mm

Simulated Saturation occurred at 90 m

Actual Simulation occurred at 68 m

Correction factor sqrt (90/68) = 1.15

This brings average to 1.10 mm



LCLS Tolerance Budget

Error Source i fi i fi Units

@ 130 m (24.2% red.)

Hor/Ver Optics Mismatch (-1)0.5 0.71 0.452 0.32

Hor/Ver Transverse Beam Offset 30 0.176 3.7 µm

Module Detuning K/K 0.060 0.400 0.024 %

Module Offset in x 1121 0.125 140 µm

Module Offset in y 268 0.298 80 µm

Quadrupole Gradient Error 8.8 0.029 0.25 %

Transverse Quadrupole Offset 4.7 0.214 1.0 µm

Break Length Error 20.3 0.049 1.0 mm

< 1.10.64</0<1.56

< 1.10.64</0<1.56

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Tolerance Budget ComponentsTolerance Budget Components



Girder Stability : Position / Temperature

Temperature fluctuations, girder deformation, and ground motion cause changes in

Undulator strength, which depends on Temperature

Beam trajectory

Quadrupole position instability, which causes Changes to the electron beam trajectory (phase errors)

Good News: Observed stability of girder positions and temperatures is better than expected.

Temperature fluctuations, girder deformation, and ground motion cause changes in

Undulator strength, which depends on Temperature

Beam trajectory

Quadrupole position instability, which causes Changes to the electron beam trajectory (phase errors)

Good News: Observed stability of girder positions and temperatures is better than expected.



Girder Stability During 2008 Winter Break

RMS Position Change < 1 µm

Alignment Diagnostics System (ADS)Alignment Diagnostics System (ADS)

Measurements show how much the girderposiiton deviatation from a straight line changed over the period of one week duringlab closure.

Measurements show how much the girderposiiton deviatation from a straight line changed over the period of one week duringlab closure.



Girder 13 Stability During 19h Operation

200 nm




Girder 15 Movement (18 h) During ROD (11 h)

>1 µm

Mechanical Hysteresis




Temperature Recording of Girder 16

REPAIR OPPORTUNITY DAY (ROD)SHUT DOWN (UND INSTALLATION)

HVAC SETPOINT ADJUSTMENT

50 mK



Temperature at all Girders

Mounted to UndulatorOn Girder

Downstream U23

Center U23

Upstream U23



K is Adjusted for Temperature Deviations



Use of (T-)Corrected K Values

K ADJUSTMENT RANGETEMPERATURE CORRECTED K

TAPER REQUIREMENT



Radiation Control and Monitoring

Undulator radiation damage is greatly reduced through Machine Protection System (MPS) hardware interlocks that inhibit beam to the undulator hall when

PEP/ANL type BLM signals are above threshold Beam loss fiber signals are above threshold Horizontal and/or vertical trajectory is outside ±1mm Comparator toroids indicate beam loss. Any of the upstream profile monitors is inserted More than 1 BFW is inserted or a BFW is moving

A regular TLD monitoring program is in place(s. below)A regular undulator circulation program will start soon (s. below)

Undulator radiation damage is greatly reduced through Machine Protection System (MPS) hardware interlocks that inhibit beam to the undulator hall when

PEP/ANL type BLM signals are above threshold Beam loss fiber signals are above threshold Horizontal and/or vertical trajectory is outside ±1mm Comparator toroids indicate beam loss. Any of the upstream profile monitors is inserted More than 1 BFW is inserted or a BFW is moving

A regular TLD monitoring program is in place(s. below)A regular undulator circulation program will start soon (s. below)



TLD Replacement Program

Thermo Luminescent Dosimeters (TLDs) are mounted inside the Undulator Hall and are regularly replaced and evaluated

Baseline 10/3/2008 – 12/9/2008 (10 TLDs) Startup 12/12/2008 – 12/17/2008 (12 TLDs) 1st Undulator 1/28/2009 – 2/4/2009 (15 TLDs) 1st Undulator 2/4/2009 – 2/11/2009 (14 TLDs) 1st Undulator 2/11/2009 – 2/18/2009 (18 TLDs) 1st Undulator 2/18/2009 – 3/2/2009 (48 TLDs) FEL Operation 3/24/2009 – 4/22/2009 (68 TLDs) FEL Operation 4/22/2009 – 5/6/2009 (125 TLDs) FEL Operation 5/6/2009 – 5/27/2009 (128 TLDs) FEL Operation 5/27/2009 – … (128 TLDs) FEL Operation …

Latest TLD placements include detection of neutrons and high energy gamma through use of moderators and W and Pb absorbers.TLD volume is expected to taper down after initial observation period.

Thermo Luminescent Dosimeters (TLDs) are mounted inside the Undulator Hall and are regularly replaced and evaluated

Baseline 10/3/2008 – 12/9/2008 (10 TLDs) Startup 12/12/2008 – 12/17/2008 (12 TLDs) 1st Undulator 1/28/2009 – 2/4/2009 (15 TLDs) 1st Undulator 2/4/2009 – 2/11/2009 (14 TLDs) 1st Undulator 2/11/2009 – 2/18/2009 (18 TLDs) 1st Undulator 2/18/2009 – 3/2/2009 (48 TLDs) FEL Operation 3/24/2009 – 4/22/2009 (68 TLDs) FEL Operation 4/22/2009 – 5/6/2009 (125 TLDs) FEL Operation 5/6/2009 – 5/27/2009 (128 TLDs) FEL Operation 5/27/2009 – … (128 TLDs) FEL Operation …

Latest TLD placements include detection of neutrons and high energy gamma through use of moderators and W and Pb absorbers.TLD volume is expected to taper down after initial observation period.



TLD Readings at First Undulator

LOCATION WEEK 1 PHOTON [rad] WEEK 2 PHOTON [rad] WEEK 3 PHOTON [rad]

U25:ANL-BLM 0.081 0.106 0.051

U25: PEP-BLM 0.042 0.048 0.030

U25: Back +X 0.065 0.008 0.033

U25: Back +Y 0.012 0.071 0.064

U25: Back -X 0.039 0.026 0.029

U25: Back +Y 0.013 0.042 0.014

U25: Front +X 0.112 0.093 0.072

U25: Front +Y 0.217 0.105 0.110

U25: Front -X 0.046 0.055 0.025

U25: Front -Y 0.141 0.123 0.093

Recorder Photon Doses about 0.1 rad per weekRecorder Photon Doses about 0.1 rad per week



SN16 Radiation Damage Test

HAS BEEN INSTALLED ON GIRDER 25 DURING BEAM OPERATION



Dose During Initial X-Ray Operation

e-folding length 8.7 me-folding length 8.7 m

Increased TLD Readings are expected to be predominantly low energy synchrotron radiation, not to cause significant magnet damageIncreased TLD Readings are expected to be predominantly low energy synchrotron radiation, not to cause significant magnet damage

[rad

]



Dose During Recent X-Ray Operation

e-folding length 8.7 me-folding length 8.7 m

Increased TLD Readings are expected to be predominantly low energy synchrotron radiation, not to cause significant magnet damageIncreased TLD Readings are expected to be predominantly low energy synchrotron radiation, not to cause significant magnet damage

neutron dose at end of undulator line about 100 mrad/week or lessneutron dose at end of undulator line about 100 mrad/week or less



TLD Readings at End of Undulator Line

LOCATION Photon Dose over 3 weeks [rad]

Downstream U32 without / with 1.6 mm Pb wrap 0.52 / 1.84

Downstream U33 without / with 1.6 mm Pb wrap 1.38 / 6.37

Downstream (about 2.5 m) U33 without / with W 0.62 / 0.05

Downstream (about 2.5 m) U33 without / with Al 0.59 / 0.31

U33 Cam Motors CM2 / CM5 0.00 / 0.02

U33 Horizontal Slide Motor SL1 0.08

On top of RFBPM Chassis U31 / U32 0.04 / 0.31

Girder Motion Electronics Racks U25 / U29 / U33 0.03 / 0.01 / 0.01

WPM Electronics Racks U25 / U31 2.08 / .08

North Side of Tunnel opposite of U33 0.08

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SN20 Radiation Damage Test

HAS BEEN INSTALLED ON GIRDER 33 DURING FEL OPERATION



Undulator Circulation Program

Undulators will be periodically removed from the Undulator Hall to be re-measured at the MMF to check for radiation damageA “test”-undulator was re-measured after several weeks of beam operation. No damage was found.First undulator that participated in FEL run was removed on June 3 and MMF testing has found it to be undamaged Depending on MMF availability, up to 2 undulators per month will be removed from the Undulator Hall for checkingAfter the undulators have been found undamaged they will be reinstalled onto the original girder

Undulators will be periodically removed from the Undulator Hall to be re-measured at the MMF to check for radiation damageA “test”-undulator was re-measured after several weeks of beam operation. No damage was found.First undulator that participated in FEL run was removed on June 3 and MMF testing has found it to be undamaged Depending on MMF availability, up to 2 undulators per month will be removed from the Undulator Hall for checkingAfter the undulators have been found undamaged they will be reinstalled onto the original girder



Undulator tuning and installation close to completionInitial beam operation went extremely smoothly: no tweaking requiredTemperature and girder stability are well within toleranceBeam loss control and radiation monitoring is in placeHigh radiation levels at initial FEL operation are expected to be predominantly low energy photons that should not generate demagnetizationVery low dose levels measured at electronics componentsUndulator circulation program has started

Undulator tuning and installation close to completionInitial beam operation went extremely smoothly: no tweaking requiredTemperature and girder stability are well within toleranceBeam loss control and radiation monitoring is in placeHigh radiation levels at initial FEL operation are expected to be predominantly low energy photons that should not generate demagnetizationVery low dose levels measured at electronics componentsUndulator circulation program has started

Summary



End of Presentation