SLAC 5045 Klystron Modulator Training Course Session 1

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SLAC 5045 Klystron Modulator Training
CourseSession 1
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Purpose of Course

• To provide for engineering and maintenance
  personnel a resource to aid in the improvements
  and upkeep of the 5045 klystron modulators.

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Course Structure

• There will be classes beginning 5/29/02 and every
  three weeks thereafter for ten total sessions.
• Each class will begin with a description of the
  design of a modulator subsystem.
• Each class will end with a time for questions and
  discussions relating to the maintenance and
  troubleshooting of the subsystem.
• These sessions are meant to be interactive!
  Please come to ask questions and to share your
  modulator know how.

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SLAC 5045 Klystron Modulator Training Course
Syllabus

• Introduction 5/29/02
• Modulator Input Power 6/19/02
• Modulator Power Supplies 7/10/02
• Modulator Pulse Forming Network 7/31/02
• Modulator Thyratron Switch 8/21/02
• Modulator Cables 9/11/02
• Modulator Controls Diagnostics 10/2/02
• Modulator Interlocks 10/23/02
• Modulator Safety 11/13/02
• Anomalous Modulators 12/4/02

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Introduction

• What is a Klystron?
• What is a Klystron Modulator?
• Klystron Modulators and the Linear Accelerator
• Linac Layout
• Modulator Block Diagram

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References for the Introduction

• The Stanford Two-Mile Accelerator, R.B. Neal,
  1968 W.A. Benjamin, Inc.
• SLAC Klystron Department web page
• SLAC Virtual Visitor Center
• AMRF web page.
• SLAC MODULATOR OPERATION AND RELIABILITY IN THE
  SLC ERA.By A.R. Donaldson, J.R. Ashton (SLAC).
  SLAC-PUB-5863, Jun 1992. 6pp. Presented at 1992
  20th Int. Power Modulator Symp., Myrtle Beach,
  SC, Jun 23-25, 1992.

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SLAC
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Linear Accelerators
Electrons and positrons may be accelerated by
injecting them into structures with traveling
electromagnetic waves.
The microwaves from the klystrons in the
Klystron Gallery are fed into the accelerator
structure via the waveguides. This creates a
pattern of electric and magnetic fields, which
form an electromagnetic wave traveling down the
accelerator. The beam energy is a function of
the energy boost per klystron and the total
number of klystrons. Note Taken from SLAC
Virtual Visitor Center
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Klystrons at SLAC
Note Taken from SLAC Klystron Department web
page.
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How a Klystron Works

• In a klystron
• The electron gun    produces a flow of
  electrons  .
• The bunching cavities    regulate the speed of
  the electrons so that they arrive in bunches at
  the output cavity.
• The bunches of electrons excite microwaves in the
  output cavity    of the klystron.
• The microwaves flow into the waveguide   ,
  which transports them to the accelerator  .
• The electrons are absorbed in the beam stop.   

Note Taken from SLAC Virtual Visitor Center
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Typical Linac RF Block Diagram
Note Taken from AMRF web page.
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What is a Klystron Modulator?

• A modulator is a power supply capable of
  generating high peak power pulses to a load.
• A modulator is designed to run in repetitive
  pulse operation.
• Ideally, a klystron modulator produces square
  wave pulses to the klystron cathode.

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Why Use a Modulator to Drive a Klystron?

• Klystron Perveance Iklystron/(Vbeam voltage)3/2
  The perveance of a 5045 is 2x10-6.
• The peak RF power from a 5045 is 65 MW.
• The power needed to achieve 65 MW of RF equals
  Vbeam voltage x Iklystron (350 kV) x (414
  A) 144.9 MW !
• Pulsed power is the right approach
• Smaller power source.
• Less cooling required. (Klystron efficiency is
  45.)
• PowerAvg. PowerPeak x Duty Cycle 144.9 MW x
  5 us x 120 Hz 86.9 kW

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5045 Klystron Modulator Specifications
Table from SLAC MODULATOR OPERATION AND
RELIABILITY IN THE SLC ERA.By A.R. Donaldson,
J.R. Ashton (SLAC). SLAC-PUB-5863, Jun 1992. 6pp.
Presented at 1992 20th Int. Power Modulator
Symp., Myrtle Beach, SC, Jun 23-25, 1992.
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Klystron and Modulator
Note Taken from SLAC Virtual Visitor Center
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SLAC Layout
Note Taken from SLAC Virtual Visitor Center
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Linac Klystron RF Power Distribution
Note Taken from SLAC Virtual Visitor Center
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Typical Linac Sector
Note Taken from AMRF web page.
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Modulator/Klystron Deployment
Table from SLAC MODULATOR OPERATION AND
RELIABILITY IN THE SLC ERA.By A.R. Donaldson,
J.R. Ashton (SLAC). SLAC-PUB-5863, Jun 1992. 6pp.
Presented at 1992 20th Int. Power Modulator
Symp., Myrtle Beach, SC, Jun 23-25, 1992.
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Modulator Block Diagram
Note Taken from The Stanford Two-Mile
Accelerator, R.B.Neal, 1968
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Modulator Thyratron Switch

• Introduction to thyratron operation
• Thyratron Ranging
• Thyratron Triggering
• Anode Reactor
• Routine Maintenance
• Troubleshooting

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Modulator Cables

• Pulse Cable
• Pulse Tank Power Cable
• Control Cables
• Fire Alarm Cable
• Power Cables
• Routine Maintenance
• Troubleshooting

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Modulator Controls Diagnostics

• Local Controls
• MKSU
• Trigger Pulse
• Diagnostics
• Cassel Box
• Routine Maintenance
• Troubleshooting

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Modulator Interlocks

• Introduction
• Personnel Protection
• Equipment Protection
• Klystron Faults
• Thyratron Faults
• Routine Maintenance
• Troubleshooting

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Modulator Safety

• Lock Tag Procedure
• PFN Tuning Procedure
• Fire Safety
• Hazardous Chemicals--MSDS

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Anomalous Modulators

• List of modulator anomalies and locations