Undulator Cavity BPM Status

1
Undulator Cavity BPM Status
2
Design Review Outline

• BPM System Design Overview
• Cavity Design
• Electronics and ADC
• Current status for phase I prototype testing
• Planning phase II prototype test
• First article and production

3
LTU and Undulator BPM System Specification
Parameter Specification Limit Condition
Resolution lt 1?m 0.2 1.0 nC /- 1 mm range
Offset Stability lt /- 1?m 1 hour /- 1 mm range 20.0 /- 0.56 Celsius
Offset Stability lt /- 3?m 24 hours /- 1 mm range 20.0 /- 0.56 Celsius
Gain Error lt /- 10 /- 1 mm range 20.0 /- 0.56 Celsius
Dynamic Range, Position /- 1 mm 10 mm diameter vacuum chamber
Dynamic Range, Intensity gt 14 dB PC Gun 0.2 1.0 nC
4
BPM System Overview Block Diagram
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X-Band Cavity BPM Design

• Each BPM has position cavity and reference cavity
• SLAC selective coupling design utilized to reduce
  monopole mode
• Iris couplers are precisely EDM into Solid Copper
  Body
• Waveguide transition brazed to body

6
Cold Test Prototype

• Non-vacuum cold test prototype
• Accelerated design verification and cold test
  development
• Removable end caps
• Presently used to verify tuning effects and test
  fixture development

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Before and After Brazing (ITS Prototype)
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Prototype Cold Test (Dipole cavity 500 micron
offset)
Parameter (500 µm offset) Predicted Measured Prototype 1 bolted end caps Measured Prototype 2 brazed end caps
Frequency TM010 8.262 GHz 8.271 GHz 8.243 GHz
Coupling TM010 -53 dB -69 dB -62 dB
Frequency TM110 11.364 GHz 11.344 GHz 11.357 GHz
Coupling TM110 -32 dB -28 dB -24 dB
Q (loaded) TM110 2704 2086 2391
X/Y Isolation TM110 -26 dB -33 dB -23 dB
Dipole to Monopole cavity Isolation lt-80 dB lt-85 dB lt-89 dB
Frequency TM020 15.825 GHz 15.767 GHz 15.785 GHz
Coupling TM020 -78 dB -64 dB -50 dB
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Baseline Design for Phase I PrototypeMiteq
X-Band Low Noise Receiver

• Existing product line
• WR 75 Waveguide Interface
• Low Noise Figure (2.7 dB)
• Budgetary price for (3 channels) 6500.00

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Prototype Receiver Specification
Parameter Specification Limit Condition
RF Frequency 11.364 GHz 20.0 /- 0.56 Celsius Dx, Dy, Intensity
Input Peak Power 50 watts peak No damage (limiter protection)
LO Frequency 11.424 GHz (2856 MHz4) 20.0 /- 0.56 Celsius 1nC, 1mm offset, 200fs BL
LO Power Range 10 dBm Max. Provide LO for 3 down converters
IF Frequency 60 MHz Min. 20.0 /- 0.56 Celsius
Noise Figure Dx and DY 2.7 dB Max. 20.0 /- 0.56 Celsius
Noise Figure Intensity (reference) 4.0 dB Max. 20.0 /- 0.56 Celsius
LO to RF Isolation 40 dB Min. 20.0 /- 0.56 Celsius
LO to IF Isolation 45 dB Min. 20.0 /- 0.56 Celsius
Output Power 14 dBm 1 dB compression
Conversion Gain 25 dB typical 20.0 /- 0.56 Celsius
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In-Tunnel Receiver Block Diagram
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Prototype X-Band Low Noise Receivers

• Conversion gain 28 dB
• Over 60 dB dynamic range
• Noise Figure 2.5 dB
• IF bandwidth 40-80 MHz
• Receiver noise floor -88 dBm assuming 20 MHz IF
  bandwidth
• Cavity BPM Sensitivity
• -54 dBm/0.2nC/1?m

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BPM System Test Approach

• Phase I
• Injector Test Stand ITS
• Install single X-Band Cavity and modified
  off-the-shelf down converter receiver
• Mount BPM on two-axis translation stage

• Phase II
• LEUTL test with PC gun
• Install three X-Band Cavities BPMs
• Mount all 3 BPMs together on a two-axis
  translation stage

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Injector Test Stand (ITS) Beam Parameters

• Charge- 1 nC single-bunch
• Bunch length- 3 - 4 ps FWHM for ps laser
• Spot size on final screen at 5.5 MeV 0.75 mm
  rms, ps laser

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(Phase I) ITS BPM Test Results

• BPM setup on X/Y translation stage
• Aligned BPM Pitch and Yaw to lt 25 ?m
• Initial beam spot size 2-3 mm rms at low charge
  (0.05 nC) at faraday cup before adding new
  focusing magnetsto reduce to 200 um rms
• Beam stability limited to 50 ?m rms. Laser
  improvements ongoing

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ITS Data Processing Development

• Cavity BPM and electronics tested using ITS beam
  line
• First raw cavity voltage outputs captured on
  scope 6/9/06
• Mover system calibration
• Testing is on-going following Aug/Sep shut-down

Hor.
Ref.
Vert.
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ITS Data Processing Development
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Waveforms acquired with sampling scope and
processed via Epics
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Normalized waveforms 0.05 nC charge
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Dipole Cavity Preliminary Test Data
Parameter Predicted Value Cold Test Data ITS Test Data
Frequency (TM110) 11.364 GHz 11.357 GHz 11.359 GHz
Q (loaded) (TM110) 2704 2391 2500
Isolation X/Y (TM110) -26 dB -23 dB lt -20 dB
Voltage Output 2.3 mV/um/nC 1.22 mV/um/nC
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(Phase II) 3 BPM Test Schedule Milestones

• Refine design and develop First Article Cavity
  BPM and support hardware
• August 06
• Start 3 BPMs
• October 06
• First unit with accelerated delivery
• October 06
• Install 3 cavity BPMs into APS LEUTL and Test
• December 06

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Prototype Phase II Cavity BPM Specification
Parameter Specification Limit (change) Condition
TM110 Frequency Dipole Cavity 11.364 GHz (11.384 GHz) 20.0 /- 0.56 Celsius
Loaded Q factor Dipole Cavity 3000 /- 200 (3500 /- 200) 20.0 /- 0.56 Celsius
Power Output TM110 Dipole Cavity -10 dBm 20.0 /- 0.56 Celsius 1nC, 1mm offset, 200fs BL
X/Y Cross Talk Dipole Cavity lt -20 dB (lt-26 dB) /- 1 mm range 20.0 /- 0.56 Celsius
TM010 Frequency Monopole Cavity 11.364 GHz (11.374 GHz) 20.0 /- 0.56 Celsius
Loaded Q factor Monopole Cavity 3000/- 200 (3500 /- 200) 20.0 /- 0.56 Celsius
Power Output TM010 Monopole Cavity -10 dBm 20.0 /- 0.56 Celsius 1nC, /-1mm offset range, 200fs BL
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Dipole Cavity Design

• Beam pipe radius 5 mm
• Cavity radius 14.937 mm (14.888 mm)
• Cavity gap 3 mm
• Distance beam axis to bottom of wg 9.5 mm (10.5
  mm)
• Waveguide 19.05 x 3 mm

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Monopole Cavity Design

• Beam pipe radius 5 mm
• Cavity radius 11.738 mm (11.477 mm)
• Cavity gap 2 mm (3 mm)
• Coupling Slot 2 x 4 mm (2.5 x 4 mm)
• Tangent to surface of cavity opening to bottom of
  waveguide1.734 mm (3.75 mm)
• Waveguide 19.05 x 3 mm

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Tuning Pins Feature Added

• Tuning pins prototyped and tested in lab
• Tuning pin simulations verify lab measurements
• Tuning pins will improve performance and
  production yield

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Design Development
First Article Design
ITS Test Unit
Cold Test Unit
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Receiver Design Changes

• Packaged 3 channel receiver
• High/Low gain feature (28/0dB) to extend dynamic
  range.
• Add a simple CW tone self-test feature

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Receiver Packaging Design

• Receiver enclosure 12.5 wide by 11 deep by 2.5
  thick (inches) with radiation shield cover
• Houses input filters local oscillator and
  down-converter
• 3-WR75 Inputs, 3-type N outputs, LO ref. input
  Type N, power and control cable

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SLAC ADC Development

• The PAD (Phase and Amplitude Detector) being
  considered for Cavity BPM ADC
• Linear Technologies LTC2208 16 bit digitizer chip
  specified to run up to 130MHz

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Phase II Data Acquisition Design Approach

• Instrument three BPMs with SLAC Built 16-bit, 130
  MSPS digitizers (PAD)
• Epics driver available
• Synchronize ADC clock with 119 MHz
• Digitize horizontal, vertical position and
  Intensity 0 to 1 volt range
• Digital down convert 40 MHz IF decaying
  exponentials

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Phase II Testing Objectives 3 BPM Test

• Test three BPM separated by fixed distance to
  determine single-shot
• Evaluate First Article Prototypes
• Complete test matrix to prove compliance to
  specification

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System Layout and Planning
Beam
X-band receiver LRU
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Production Phase

• Production of 2 BPMs for LTU 04/07
• Production of 6 BPMs for undulator 04/07
• Production of 9 BPMs for undulator 06/07
• Production of 9 BPMs for undulator 08/07
• Production of 10 BPMs for undulator 10/07
• Spares 12/07

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Summary

• X-Band Cavity BPM development ongoing
• Bolt-together prototype (non-vacuum) complete
• ITS prototype testing ongoing
• 3 BPM test prototype design enhancements ongoing
• Receiver Prototype Development
• First Prototype installed in ITS with good
  results
• 3 BPM test prototype design incorporates high/low
  gain, self-test and final packaging
• Data Acquisition and Test
• Collaborating with SLAC to use the same ADC as
  SLAC LINAC BPM upgrade