Difference between revisions of "PHY542 spring 2020"

Revision as of 20:23, 24 January 2020

Course Overview

The course is intended for graduate students who want to gain knowledge about contemporary particle accelerators and their applications. During the semester, students will learn the basics on accelerator physics principles and accelerator operation as well have the unique opportunity to gain “hands-on” experience on an operational accelerator. Students will also learn advanced computational techniques in order to model and analyze their experiments.

Learning Goals

The course will cover a wide array of the measurements and manipulations that are needed for beam dynamics studies. Upon completion, students are expected to understand the basic principles and relations of beam dynamics, many of which they will have experimentally verified. Furthermore, they will have gained experience in measurement techniques and analysis of experimental observations.

While emphasis will be given on experiments, it will also offer exposure to the latest accelerator computer simulation techniques.

Several major topics will be covered during the semester:

• source physics
• magnet measurements
• optical imaging and processing using both fast and integrating devices
• phase space mapping and emittance measurement
• longitudinal dynamics and energy spread, beam control

Overall, students will be exposed to a number of state-of-the-art diagnostics and experimental techniques.

Course Procedure

A total of 7 experiments will be conducted focusing in three different research areas: Beam control and focusing, beam diagnostic techniques, and electromagnetic phenomena on particle beams. The students will have hands-on experience on an operational accelerator and will be responsible for setting up the equipment, obtaining their own measurements, and analyzing the data. For same experiments students will be asked to model the experiments and compare results with measurements. Three lectures will be given – one for each group of experiments. During the lecture the students will learn the basics on beam diagnostic and imaging methods, beam manipulation techniques as well as the basic theory on electromagnetic phenomena on particle beans. A fourth lecture will be devoted on advanced computation techniques for analyzing results in accelerator physics. The primary simulation codes for this class will be ASTRA and ELEGANT while some experience with MATLAB, or Mathematica will be useful. During the semester, students will prepare two reports (each at different group areas). The content should include: 1) A background section which describes the experiment and explain the objectives, 2) A summary of measurements taken in the lab, 3) detailed data analysis and discussion, and 4) conclusion remarks. In addition, at the end of semester each student will be asked to prepare a presentation covering an experiment from a different group of experiments from any of the reports

LOCATION: The first class will be at Stony Brook University, Chemistry Building 124 All remaining classes will be at Brookhaven National Laboratory (BNL), Building 820

IMPORTANT: When you arrive at BNL's main gate, please inform the guard you are attending the Advanced Accelerator Laboratory Course at the ATF. You may be requested to check in at the nearby security trailer or research support building (Bldg. 400), where proper visitor identification may be required [1]. We highly recommend that you will arrive no later than 3:30 pm during your first time for registration.

Transportation info can be found here: [2] A list of BNL maps can be found here: [3]

Textbook and suggested materials

• “The Theory and Design of Charged Particle Beams” by Martin Reiser, published by Wiley (1994)

• “Fundamentals of Beam Physics” by James Rosenzweig, published by Oxford 2003

• “Classical Electrodynamics”, third edition, by J.D. Jackson, published by Wiley (1999). Chapters 11 and 12 are of particular relevance to this course.

• Accelerator Physics, by S. Y. Lee

• Data Reduction and Error Analysis for the Physical Sciences, P.R.Bevington & D.K.

Robinson (2nd or 3rd ed., McGraw-Hill Inc., 1992, 2002)

Grading

• 20% active participation in the lab
• 60% lab report
• 20% presentation

There will be no final exam.

List of topics

The following topics are taken mostly from Physical Review Letters. All topics correspond to breakthrough experiments conducted at the Accelerator Test Facility.Two examples are here:

• 1. Dielectric Wakefield Acceleration of a Relativistic Electron Beam in a Slab-Symmetric Dielectric Lined Waveguide Download

• 2. Seeding of Self-Modulation Instability of a Long Electron Bunch in a Plasma Download

• 3. Experimental Observation of Suppression of Coherent-Synchrotron-Radiation–Induced Beam-Energy Spread with Shielding Plates Download

• 4. Generation of trains of electron microbunches with adjustable subpicosecond spacing Download

• 5. Subpicosecond Bunch Train Production for a Tunable mJ Level THz SourceDownload

• 6. High-quality electron beams from a helical inverse free-electron laser acceleratorDownload

• 7. Experimental Study of Current Filamentation Instability Download

• 8. Simple method for generating adjustable trains of picosecond electron bunches Download

• 9. Resonant excitation of coherent Cerenkov radiation in dielectric lined waveguides Download

NEW: Project topics for Spring 2015 class can be downloaded here: Projects

• 10. "A Plasma Physics Perspective on Accelerating Electrons" by Navid Vafaei-Najafabadi Download

List of experiments

• Group A: Beam control and focusing
• A1: Measurement of quantum efficiency

During this lab activity the students will learn to setup and operate a photocathode gun, measure electron beam charge, measure the photocathode yield –e.g. quantum efficiency (QE), and study its dependence with the laser parameters.

• A2: Magnetic measurement:

During this activity the students will measure the magnetic profile of a quadrupole lens by using a strained wire. Then, they will model a particle beam passing through a quadrupole that uses the focusing field measured in the experiment. The impact of magnet misalignments or positioning errors on beam dynamics will be numerically analyzed. .

• Group B: Beam diagnostic techniques
• B1: Emittance measurement with a quad scan

The students will vary the magnet focusing strength (measured in A2), record beam images for each setting on a fluorescent screen and measure rms beam size. Then, by fitting the data to a polynomial fit, they will measure the beam emittance (by using the theory taught in class). The students will also compare the measurements with predictions from numerical calculations.

• B2: Emittance measurement with a screen method

The students will steer the beam through four profile monitors and record images. Then they will analyze the images and obtain the beam size on each screen. Using theory (taught in class) they will obtain the beam emittance using statistical analysis.

• B3: Phase-space mapping

During this exercise the students will measure the beam profile for different magnet settings. Then using tomographic principles (taught in class) will obtain the 2-D beam phase-space by using the measured 1-D profiles. From the phase-space and by doing appropriate statistical analysis they will extract important beam parameters such as the beam size and divergence.

• Group C: Electromagnetic effects on particle beams
• C1: Coherent synchrotron radiation

Coherent synchrotron radiation (CSR) effect is responsible for energy spread increase and emittance degradation for short electron bunches in systems included bending magnets. Students will conduct a set of energy profile measurements using beam profile monitor installed at location with large dispersion. As a results of measurements students will be able to reconstructs CSR effect dependency on bunch length, charge per bunch and peak current. These measurements could be supported by numerical simulation using accelerator design codes (e.g. ELEGANT).

• C2: Generation of bunched beams

In this clas s students will learn mask technique developed at ATF: the idea, purpose and procedure. Mask transmission contrast measurements will be proposed for practice. During measurements students will vary beatatron beam size by control quadrupoles triplet strength located upstream of beamline dogleg section. Series of saved BPM images have to be analyzed, dependence of mask transmission contrast from beam can be derived. Data supposed to be filtered and averaged, error from charge fluctuations can be estimated.

Safety Training

All students must complete online general training “Guest Site Orientation” (TQ-GSO).

In addition, here is the list of online ATF - specific training that you should also take prior to your arrival at ATF:

- Static Magnetic Fields

- LOTO Affected (Awareness)

- ATF Awareness

Note:

- Any student with medical conditions/implants affected by magnetic fields needs medical clearance prior to entry into exp hall or work with magnetic measurements.

Course Schedule