U.S. Particle Accelerator School

SRF Technology: Practices and Hands-On Measurements course

Sponsoring University:

Old Dominion University


SRF Technology: Practices and Hands-On Measurements

Charles Reece, Rongli Geng, Tom Powers, Haipeng Wang, Joe Matalevich, Frank Marhauser and Ari Palczewski, Jefferson Lab and John Mammosser, Oak Ridge National Lab

Purpose and Audience
The purpose of the course is to introduce students to the SRF technology and the procedures and techniques used in the production and testing of SRF cavities. It will focus on multi-cell elliptical structures. The course is intended to be mainly hands-on work with cavities using the processing, test and measurement systems available at the Jefferson Lab SRF Institute. The course is intended for graduate-level students with a background in SRF technology, individuals working in the field, and individuals intending on working in the field.

Students should have an undergraduate degree in physics or engineering with a basic knowledge of the use of radio frequency test equipment such as vector network analyzers, spectrum analyzers, and power measurement equipment. Having previously completed the USPAS “Microwave Measurements” and "Fundamentals of Accelerator Physics & Technology" classes is desirable. Students will be required to take several basic on-line safety training classes in advance of the course.

Class will be held at Jefferson Lab and is limited to 16 students. A resume/CV and a letter of recommendation is required from each applicant. Please submit these documents to the USPAS Office, uspas@fnal.gov. Preference will be given to participants who take the course for a grade.

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

By the end of the course the student should be familiar with the practical aspects of SRF technology and cavity preparation and processing as well as how to set up and perform a 2K test on an SRF cavity.

Instructional Method
The course will be split between lectures and practical laboratory experiments performed in the SRF production facilities at Jefferson Lab. The plan is to have one or more experiments on each of the basic topics covered in the lectures. Students will work in small groups and rotate from station to station during the 10 day class. Laboratory reports will be required describing the results of the work. Examples of such experiments are: tuning a multi-cell cavity for field flatness, clean room assembly techniques, vertical testing of an SRF cavity at 2K, impulse hammer testing of structures to determine their resonant frequencies, background microphonic measurements of SRF cavities.

Topics Covered

  1. SRF Cavity basics - theory
  2. Niobium cavity surface physics and inspection.
  3. Types of chemical and mechanical surface processing, including chemical safety considerations.
  4. Cavity tuning and setup of fundamental power coupler and field probe for vertical tests.
  5. Clean room protocol and techniques.
  6. Vertical testing of SRF cavities.
  7. Helium processing to reduce field emission
  8. Vibration and modal analysis basics, microphonics and impulse response testing.
  9. HOM simulation and measurements.
  10. Testing of cavities in cryomodules and over-coupled Qo measurements.

Reading Requirements
The course will follow on-line technical notes and publications from the instructors.

Credit Requirements
Students will be evaluated based on their participation and contributions during the Lab work (40%), and laboratory reports (60%).

IU/USPAS course: Physics 571