U.S. Particle Accelerator School

Microwave Measurements and Beam Instrumentation Laboratory

Sponsors:

University of California, San Diego Extension

Course Name:

Microwave Measurements and Beam Instrumentation Laboratory

Instructors:

Derun Li;  Lawrence Doolittle; Gang Huang; Tianhuan Luo; Stefano DeSantis, Lawrence Berkeley National Lab


Purpose and Audience
Modern accelerators rely on beam manipulations using electromagnetic fields at microwave RF frequencies. This laboratory course introduces the student to RF and microwave technology and laboratory methods employed for its characterization. The course consists primarily of laboratory exercises.  Short lectures introduce essential features of topics covered in the laboratory exercises.

Prerequisites
Undergraduate level Electromagnetism and the knowledge of basic accelerator science and technology at the level of USPAS course Fundamentals of Accelerator Physics and Technology with Simulations and Measurements Lab or USPAS graduate Accelerator Physics is required.

It is the responsibility of the student to ensure that he or she meets the course prerequisites or has equivalent experience.

Objectives
Provide the student with practical experience in measurements of RF and microwave accelerator hardware and signals using modern equipment.

Instructional Method
This course includes a series of lectures introducing fundamental concepts of microwave theory and the lab topics during morning sessions, and extensive afternoon lab sessions to demonstrate theoretical concepts. These hand-on labs include:

  1. Spectrum Analyzer: Measurement of signals on a spectrum analyzer to understand resolution bandwidth, video bandwidth, dynamic range, noise, etc.
  2. Time Domain Reflectometry (TDR): Measure characteristics of various connector families, transmission lines, and complex loads.
  3. Beam Impedance: Use the wire method to measure the beam impedance of an accelerator element.
  4. Beam Signals: Utilize an arbitrary function generator to simulate beam signals from the accelerator; Amplitude Modulation (AM) for betatron signals, Frequency Modulation (FM) for synchrotron signals.
  5. Beam Pickups and Kickers: Measure and understand to performance of a stripline used as either a beam pickup or kicker.
  6. Matching: Design and build a simple single stub transmission line matching circuit.
  7. RF Cavities: Measure mode spectrums of a cavity, the cavity coupling, loaded and unloaded Q, the electric field distribution and R/Q of a cavity by the bead pull method.
  8. Linac Structures: Measure mode spectrums of coupled cavities, loaded and unloaded Q; identify and understand the coupled modes and phase advance between cavities.
  9. Vector Signal Analyzer: Use of a vector signal analyzer for measuring beam signals.

Instructors will be actively involved with each of the students during the course of each day and each experiment. The students will be evaluated by one-on-one discussions about the experiments. Students will submit written lab reports and solutions to the homework assignments. Instructors will be available for guidance during evening homework sessions.

Course Content
Topics covered include:

  1. Microwave Measurements in the time and frequency domains, basics of spectrum analyzers, vector signal analyzers, and time domain reflectometers.
  2. Transmission lines, complex impedance, reflection coefficients.
  3. Microwave measurements with a Vector Network Analyzer; basics of vector network analyzers.
  4. Stripline pickups and kickers.
  5. Beam signals for circular accelerators; beam spectrums, power spectral density, betatron and synchrotron signals.
  6. Beam impedance and methods for measurements of.
  7. Impedance matching; basic matching devices.
  8. RF cavity and linac structure measurements; cavity and coupled cavity basics, bead pull, coupling, and cavity bandwidth.


Reading Requirements
(to be provided by the USPAS) Microwave Engineering by David Pozar (fourth edition), John Wiley and Sons (2011).  

Credit Requirements
Students will be evaluated based on of laboratory reports (50% course grade), grades and lab performance in discussions with instructors (50% course grade). 


UC San Diego course number: PHYS 40008
Indiana University course number: Physics 571, Special Topics in Physics of Beams
Michigan State University course number: PHY 963, U.S. Particle Accelerator School
MIT course number: 8.790, Accelerator Physics