The experiments you will perform in PHYS 334 are based on cornerstone, often Nobel Prize-winning work. In the instructional laboratory setting, they often take the form of laboratory_exercises_designed to show physics phenomena or teach specific skills, but when possible we have also tried to build in opportunities for work that more closely resembles_research_ (e.g. doing literature searches, making experimental design or measurement decisions, working collaboratively, and iterating on ideas.) We hope that these experiments provide a fuller understanding of physics and preparation for future research.

By offering the Advanced Laboratory Course, we hope to shed light on the following questions:

1. How do we develop a systematic process of doing experiments? - How should we interpret theoretical concepts in the real world? - What experimental techniques are available for producing and analyzing data? - With what degree of confidence can we trust our measurements and interpretations? - How well does a theory represent physical reality? - How do we collaborate with experimental partners? - How do we best communicate our findings to others?

These questions are of fundamental importance to experimental physics, yet are not generally addressed by reading textbooks, attending lectures or doing homework problem sets. Thus, to provide a more complete understanding of physics, we offer these laboratory exercises as a supplement to the other modes of learning.

All students begin with an introductory experiment:

• Gamma Cross Sections

This experiment helps to familiarize students with the course format and expectations, and gives students an opportunity to collect data, keep a lab notebook, write a report, and receive feedback before the longer, more sophisticated experiments begin.

For the remainder of the course, students will work on one longer experiment, selected from the following repertoire:

• Mossbauer Effect
• Compton Scattering
• X-Ray Studies
• Pulsed Nuclear Magnetic Resonance
• Brownian Motion
• Drop Pinch-Off
• Optical Pumping

Students are asked to rank the experiments in order of preference, but first choices cannot always be accommodated.

Faculty typically divide these experiments into two groups, with each faculty member “responsible” for half the experiments. The instructor for a particular experiment will grade the reports for that experiment and provide help in lab when possible. The faculty will also participate in the presentation discussion and grading.

Lab staff are on hand to help students start experiments and work with students as problems arise.

In-lab restrictions

Due to social distancing requirements, students will work by themselves on projects (not with a partner as in a usual year). Students will be split into two groups for scheduling purposes:

• Group A will have access to the lab on Tuesday and Thursdays.
• Group B will have access to the lab on Wednesdays and Fridays.

Each student will be assigned to a lab room, and that room will only be used by that student; all equipment will be provided, but it is the responsibility of the student to disinfect the space before and after use each day. 

Each experiment is divided into two parts

• The first part of each experiment serves as an introduction to using the apparatus, developing proper measurement techniques, and understanding basic theory. This portion of the experiment may include performing calibrations, making preliminary measurements, characterizing apparatus properties, or performing simple experiments, and it is designed to give them the skills needed to perform a meaningful measurement in part two.
• The second part of each experiment is a more open-ended exploration of the phenomena previewed in the first part. Certain experiments also include the ability for a student to customize what specific things they investigate.

Students will schedule at least two “group meetings” with the instructor during the project

First meeting (approximately end of Week 4/start of Week 5)

• At the end of the first part of the project, students will meet with instructors to discuss their progress and to get approval for work completed or planned. The goal of this meeting is to convince the instructors that the student understands what they are doing and whether they are doing well enough to proceed to the more open-ended part of the experiment. Students are expected to do the following at this meeting:
  • discuss the background theory being explored and why the apparatus and methods used in this experiment are appropriate for this purpose;
  • demonstrate an understanding of the apparatus and techniques used in part one and to be used in part two;
  • present some analysis of the part one data, including discussions of sources of uncertainty, calibrations, etc; and
  • propose a set of goals for the second part of the experiment and outline a plan for achieving them.
• This meeting should accomplishes the following:
  • catch instances where students are not understanding what they are doing so that they can be corrected or instructed to return to the lab before proceeding. For example:
    • If a student cannot clearly articulate how the detector works, or if they cannot answer questions about how measurements (including calibrations) were carried out, they are not ready to proceed and should be directed to return to the lab or to review the manual and resources;
    • If a student cannot present data for a part of the experiment or if the data are inconsistent with their expectations (or the expectations of the lab staff or faculty), they are not ready to proceed and will need to collect new data;
    • If a student is not able to make basic interpretations about the data they have analyzed or cannot discuss the sources of error or propagation of uncertainties, they are not ready to proceed and may need to do more analysis;
  • allow the instructors to assess the student's abilities and make suggestions which will help the students get more out the experiment. For example,
    • a particularly strong student could be given a more challenging task for their second part or be allowed to modify the suggested project to explore a topic of their own choosing; or
    • a student who is struggling, on the other hand, could be tasked with revising parts of the first part, especially if it is believed that they will learn more that way than by letting them proceed to the nominally prescribed second part.
  • help the students to better understand what the faculty – who will be grading their reports and presentations – expect from them.
  • provide an experience that is more like a real research project with the opportunity to do some work in the lab, do intermediate analysis, go back into the lab to explore questions which arise from doing the intermediate analysis, and iterate towards making the final measurements.
• The meeting with instructors is not a formal presentation, per se, but a student does need to be prepared with completed plots, data tables, sketches, analysis, etc. It is suggested that students prepare presentation slides, computer images, or print-outs for these meetings.

Second meeting (approximately end of Week 7/start of Week 8)

• As the student reaches the end of the second part of the project, they will again meet with instructors. This is the final opportunity to show progress and get feedback prior to the final presentation and report.