The experiments you will perform in PHYS 334 are based on cornerstone, often Nobel Prize-winning work. In the instructional laboratory setting they may be better understood as laboratory exercises, not research. We hope that they provide fuller understanding of physics and preparation for research.

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

• 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 in pairs on two longer experiments, selected from the following repertoire:

• Optical Pumping
• Pulsed Nuclear Magnetic Resonance
• Compton Scattering
• X-Ray Studies

Students are asked to rank the experiments in order of preference. We will do our best to accommodate, but we cannot guarantee particular preferences.

The faculty instructors will grade the reports 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.

For the introductory experiment, each student will work by themselves in order to make sure that everyone gets practice with every step of conducting an experiment.

For the two longer projects, students will work in pairs in the lab. Students should do their own individual analysis (including doing all their own plots, fits, calculations, etc.), but collaboration and conversation between partners is allowed and encouraged.

Students may not work alone in the lab. Both partners should be present for all data taking, to ensure safety and to ensure that all students understand how the data were collected. All students are expected to arrive at the beginning of lab on each start-up day so that instructors can provide guidance and safety instruction. See the PHYS 334 Course Calendar for details on the schedule.

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 students 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. It is assumed that the work done in the second part will be the majority (but not all) of what is discussed in the final report and presentation.

There is no firm division between the two parts. It is up to each group (in consultation with the lab staff and instructors) to decide when they are ready to move on the open-ended explorations.

Students are given several full weeks for each experiment:

• Both partners must attend the first day of each experiment (in order to get an introduction to the equipment and to hear safety instructions). After that, students may decide their own schedule given the available days in lab.
  • Use the provided time wisely! All data collection must occur during the provided time and no one will not be allowed in the lab outside the provided hours. Get started early and work efficiently.
  • Both partners must attend lab at the same time. Students may not work alone (without prior discussion with lab staff and faculty).

Students will meet informally (approximately weekly) with the instructors. These are not formal meetings or presentations, but students should be prepared to discuss their progress and share results. In particular, students should be prepared for the following:

• to discuss the background theory being explored and why the apparatus and methods used in this experiment are appropriate for this purpose;
• to demonstrate an understanding of the apparatus and measurement techniques;
• to present analysis of data, including discussions of sources of uncertainty, calibrations, etc; and
• to propose goals for upcoming work and to outline a plan for achieving those goals.

These meetings are meant to accomplish the following:

• to 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;
• to allow the instructors to assess the student's abilities and make suggestions which will help the students get more out the experiment.
• to help the students to better understand what the faculty – who will be grading their reports and presentations – expect from them.
• to 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.

Each student will be graded on the following:

• Lab participation
  • Preparing for and attending lab when scheduled
  • Behaving in a professional manner while in the lab
  • Preparing for and participating in weekly group meetings
• Three individual reports
  • Introduction: Gamma Cross Sections report
  • Experiment 1
  • Experiment 2
• Two group presentations
  • Experiment 1
  • Experiment 2

The lab report should be in a Physical Review Letters format, (~4-6 pages, including figures). Submit a single PDF (no Microsoft Word), and include the following:

• Title, author, and abstract
• Introduction (including the significance of this experiment in modern physics)
• Theoretical background
• Experimental setup and methods
• Data/results (shown in figures with fits/predictions and error bars)
• Discussion/conclusions (including, for example, discrepancy between measured and literature values)
• Ideas to improve the experiment

Figures should…

• … be large enough to be legible,
• … have labeled axes (with font size for axis labels and legends large enough for publication),
• … have tick marks on all sides,
• … have clear, large, and unique symbols for different types of data or predictions, and
• … use lines that are of sufficient weight for publication.

The captions are particularly important, and should provide a self-contained complete description of the figure and its meaning.

At the end of each experiment (and before the report is submitted), students will do a group presentation. Each member of the pair working on an experiment should contribute to the talk and split work (and speaking time) equitably.

Each talk should be 20 minutes (plus 10 minutes for questions). There will be a hard cutoff at 20 minutes, so please practice your talk beforehand!