People

• Rich Harding, Developmental Technician, 893-2553, harding@rot.physics.ucsb.edu
• Daniel Duarte, graduate teaching assistant, duarte@physics.ucsb.edu
• Alfredo Alexander-Katz, graduate teaching assistant, ajar@physics.ucsb.edu

Having survived Ph128a, you are now ready for Ph128b. Last quarter, you learned that for your work in the laboratory to be effective, you have to invest a large amount of time and effort into discovering what is really going on.. Many students learned that this can be a lot of fun!

I have tried to emphasize a central point about this course. Our main goal is to train you in the methodology, mind-set, and habits of a research scientist. This goal sets this course apart from the usual physics lecture course, where the main goal is to teach you physics, as well as problem-solving skills. Here are some characteristics of a research-oriented approach:

• Research Methodology: be systematic and organized; repeat measurements to check for reproducibility; vary experimental parameters one by one; understand what the apparatus does-don't just treat it like a black box; record all the relevant conditions of your measurements; make lots of plots of your data and try to understand what's going on-don't just list the numbers in your logbook without scrutinizing them.
• Research Mind-set: be a careful observer-don't just record what you expect to see, or what somewhat told you that you ought to see---record what you actually do see; be skeptical-think of ways in which you might have made an error or overlooked an important effect; estimate meaningful error bars, don't just cook something up (I can easily tell the difference!).
• Research Habits: be professional in how you work with your partner and with the equipment; use your time well; pay special attention to safety issues; record your data carefully and honestly.

The Experiments
 
You will choose four experiments, spending two weeks on each one. The list of possible experiments for this quarter is:

1. Mossbauer effect
2. Molecular spectra
3. Nuclear magnetic resonance
4. Surface plasmons
5. X-ray diffraction crystallography
6. Zeeman effect
7. Quantum Hall effect
8. Vacuum Techniques.

The last experiment listed above, vacuum techniques, was also available during Ph 128a, but several groups did not do it. Since it is good experience, we have set it up for this quarter also.

Safety

There are important safety issues in some experiments. This is particularly important in Ph 128b, where we use an X-ray machine and radioactive sources, but there are also safety issues in some of the Ph 128a experiments. I require that you start each experiment by doing an assessment of the safety issues. Please work like a professional and be actively involved in your own safety:

1. Look for safety-related information in the lab manual.
2. Look for safety-related information in the manuals for the equipment.
3. Ask me, the T.A.s, or Rich Harding about anything that concerns you.
4. Record important safety-related information in your logbook.

1. Intense light sources: lasers or gas discharge tubes. Never look directly into a laser beam. In addition, be careful not to look into a mirror or other polished surface that may reflect laser light directly into your eye. When working with lasers, it is always a good idea to keep the level of your eyes substantially above the level of the laser beam. Avoid looking directly at gas discharge tubes. In some experiments, we have provided eye goggles. If you would like a pair but they aren't around for some reason, feel free to ask us and we will get some.
2. Electrical hazards (high voltage);
3. High-field magnets can pull tools out of your hands.
4. Liquid nitrogen and liquid helium (vacuum lab, surface plasmons, quantum Hall effect)
5. X-ray machines, radioactive sources (Ph 128b). Note that you must wear a film badge to work in the room for these experiments (Mossbauer effect, X-ray crystallography). This film badge will be specifically signed out to you.

THE MOST IMPORTANT RULE OF THIS CLASS, WHICH MUST NOT BE BROKEN IS:

Class Requirements

The requirements are:

1. Do four experiments, and keep a good logbook record of each one. The logbooks should not just be spiral notebooks. Please keep two separate logbooks to facilitate grading; the T.A.s will grade one while you are using the other for your next experiment.
2. Give one talk; this will be after the second experiment, and it can be on either of the first two experiments. You will give this talk jointly with your lab partner using transparencies and an overhead projector. We will provide blank write-on transparencies, but you should get your own pens. The best ones are Staedtler Lumocolor Fine-point permanent pens. You may also use a computer to generate your talk. You will then need to use a different kind of transparencies.
3. Write one abstract. The abstract is about one paragraph long and will be due after the third experiment. It can be on either of the experiments that were not the subject of your talk.
4. Write one full scientific research paper. The paper will be due after you complete all four experiments, but it may not be on the same experiment as the one your give your talk on. It may be on the one you have written your abstract for, but in general you will need to rewrite your abstract.

1. Experiments + logbooks: 75%
2. Talk: 8%
3. Abstract and Paper: 17%

There are several different goals for this class.

• Learn to work in a laboratory. We are trying to train you not just in physics knowledge, but also in the methods of working scientists in almost any field.
• Develop an approach that is systematic, methodical, careful, and organized.
• Be tough-minded and skeptical.
• Prepare ahead of time and try to anticipate the issues that you will need to address. This is extremely helpful in using your time in the lab efficiently. In many real-world experiments, you have limited access to a shared piece of equipment, such as an expensive telescope, and preparing yourself in advance gives you a much better chance to complete your investigation within the allotted time.
• Understand the sources of experimental uncertainty and the limitations of your apparatus. Effort spent on understanding how your equipment works is almost always rewarded with more reliable results.
• Learn how to record results and how to describe your setup and procedures so that the conditions under which your results were obtained are completely specified.
• Learn proper methods of data analysis.
• Learn how to draw conclusions that are specific, meaningful, and justified.
• Learn some modern physics. In your classical mechanics and electromagnetism classes, you are learning physics that was developed about 100 years ago; in quantum mechanics, you are learning physics from the 1920s and 1930s. In this class, you will learn some physics that is based on much more recent work. This will be challenging, since you may not have encountered much of this physics in your theoretical classes.
• Learn skills for giving talks and writing papers. These skill have a very wide applicability. They are extremely important in any scientific field and in many non-scientific jobs as well.
• Learn to obtain information from many sources, not just a single textbook.

Schedule: dates are specified as M, W (T, Th) for each week.

 
 

Week	Dates	Remarks
1	Jan 6 (7)	Orientation, reading
2	Jan 11, 13 (12, 14)	Orientation, Expt 1
3	Jan 18x, 20 (19, 21)	Expt 1 x=MLK holiday
4	Jan 25, 27 26, 28)	Expt 1
5	Feb 1, 3 ( 2, 4)	Expt 2
6	Feb 8, 10 (9, 11)	Expt 2
7	Feb 15, 17 (16, 18)	Expt 3; talks on Feb 15, 17
8	Feb 22, 24 (23, 25)	Expt 3
9	Mar 1, 3 (2, 4)	Expt 4
10	Mar 8, 10 (9, 11)	Expt 4
11	Mar 15, 17 (16,18)	Finals week: paper due Mar 25

 

Some important dates:

• For the M, W section, the talks will be on Mon, Feb 15
• For the T, Th section, the talks will be on Tues, Feb 16
• For the M, W section, there is one holiday, Monday, Jan 18. For this reason, the M, W section will start its experiments on Weds., Jan 13.
• The papers will be due on Thurs., Mar. 25. Note, however, that since you can write the paper on any experiment except the one that you give your talk on, you could in principle hand it in earlier!
• J.R. at Fermilab on Jan. 14, 15; at SLAC Feb 18, 22-25.

The logbooks will be due one week after you complete the experiment. Thus, for the M, W section, the logbooks will be due on the W following the two week period for the experiment; for the T, Th section, they will be due on the Th following the two week period for the experiment. The logbooks will graded on a scale from 1 to 50. Late logbooks will be accepted, but with 3 points deducted for each day late. If special circumstances arise, please discuss them with me as soon as possible.
 
Talks (same as Fall quarter)
 
Each group will give a 15 minute talk, which will be followed by 5 to 10 minutes of questions. The talk should contain

1. A title slide, with title, authors, and main goals of the experiment.
2. 2-4 of slides on theoretical background.
3. 2-4 slides on the method.
4. 2-4 slides on the results and conclusions.

make sure that it fits into 15 minutes. Sometimes, extra or "backup" slides are useful during the question period. The talk should be divided between the two lab partners, with roughly equal time for each student.
 
Paper (slightly changed from Fall quarter-see "Conclusions")
 
The paper should contain the following sections:

1. Abstract
2. Theoretical Discussion
3. Methods and Procedures
4. Results
5. Interpretation and Discussion
6. References

The abstract is meant to be a stand-alone description of the work-it should succinctly state what was done and what the results were. It should not refer to any other section of the paper, and it should not go into the theory, except perhaps very briefly. An abstract should not read like an introduction, which contains background information and is not a summary of the results. You should include the numerical values of important measurements, with their uncertainties. A person opening up the journal to your article will read the abstract first. If they are busy, this may be all that they will ever read! 

Theory
 
You should write a section on the theory behind your experiment. Do not mix your results or interpretation into this section, which should be 2-4 pages. (If you want to write more, it's fine with me.)
 
Experimental Methods and Procedures
 
Include at least one clear diagram of the experimental setup. Be sure to describe your experimental methods in detail. The length of this section will depend on the experiment that you did, but as a guideline, it should be between 3 to 5 pages. Detailed figures add a lot to the clarity of such descriptions.

Results
 
Tables are great for summarizing results. In some cases, graphs are preferable to tables, since they make it much easier to see relationships in the data. In fact, a lot of students miss important observations because they don't bother to graph their data. Be sure to include a discussion of how you estimated your experimental uncertainties in the raw data and how you propagated these uncertainties into your final results.
 
Discussion and Interpretation
 
I prefer to have the interpretation of the results in a separate section from the results themselves, since it explicitly separates what you measured from your interpretation. This rule may not apply to all situations, so if there is a strong reason to combine this section with that on Results, you can do that.
 
Conclusions
 
I didn't require you to write this section last quarter, but any scientific paper has one. This section, one or two paragraphs long, is quite similar to the abstract but need not be quite as terse and bare bones. Very often, when I read a paper I do the following: (1) read the abstract, (2) look at the figures and tables, (3) read the conclusions. Most of the time, that's all I have time for. If the paper is very important, I'll read the rest!
 
References
 
If there are important theoretical or experimental results that you wish to use in your paper, they should be referenced. In the body of the text, put a reference number, and  list the references in numerical order in this section.
 
Good luck!