Endgame and status as of April 13th
Groups and Lab assignments
Electronic logbook (ELOG)
This semester we will be using the electronic logbook to store your data and upload your lab reports, pictures etc. Once you know what group you are in, you can go to the web page below and create an account for yourself in the correct section (Check the times!) and group (check your group assignment above).
Plan for the semester
For each lab below, I have written down what I think are the important hypotheses to address in your lab report. The laboratory writeups and procedures supplied on the web page are there to let you become familiar with the experimental techniques and the questions asked in the writeups are meant to stimulate your thinking. The questions from the write-ups are useful, and I expect you to answer them. I've added some notes on each experiment to guide your (short! 1-3 pages!) lab report. Be sure your arguments are consistent with your data and analysis.
Instructor: Will Johns < will.johns@vanderbilt.edu>
Office: SC6906 and SC6924
Phone: 34(3-8295)
Office Hours: Thursday Afternoon before colloquium (You can try other times too, I may be busy.)
TA: Aroshan Jayasinghe <aroshan.k.jayasinghe@vanderbilt.edu>
You are required use the electronic logbook that you used last semester. Please include in your logbook your notes and your primary data and observations. The bulk of your work should be in your lab book. Your lab book should be kept in a way that lets your work be repeated by other people. (Especially me!) If I can't repeat your analysis from the supplied information, I can't grade your report.
In your lab report, please summarize your findings, including any error estimates you make. Attach it to your notes etc. in the Electronic lab book
The lab report for a particular lab is nominally due one week after you finish the analysis in the class period following the data taking. In principle, the summary should not take a great deal of outside lab time. If you are doing things right, you will spend more time preparing for the lab and doing the analysis in class than writing the summary.
If possible, you should take some time and ask someone who is doing the lab you are going to work on next 1) what to watch out for, 2) what they are doing, and 3) can I see how that works? An investment of a few minutes here can save you an hour or more when you do the lab.
The lab has traditionally been worth 25% of your 226W grade. Each Lab report gets a score of 100 points. 50 of those points are for your results being consistent with your data, and for your data being consistent with what you were supposed to be doing. (I.e. you can't measure the outside temperature instead of the muon lifetime and say what the outside temperature was in your report and expect 50 points! Likewise, if you made your best effort to take the data and it's just plain wrong, and you report this well, this is an honest report and I can't see knocking off points because of that.) So I really need your summary in addition to the copy of the lab book pages. The remaining 50 points are for how you handled the questions asked in the lab write up and how well you addressed the hypothesis and summarized you results in the lab report.
We will have 14 lab periods together, though the first period consists of an introduction to fitting a straight line and a radiation safety orientation. The Muon lab is set to collect data for a week, but the other experiments have been done in a single week. Additionally, there is an extra lab period for each experiment devoted to doing your analysis.
Keep a good logbook with all your data and notes in it. Keep your summary (lab report) useful and correct (and brief if possible). I will mark reports up and have you rewrite them.
If you have an idea for an experiment you would like to perform, but you don't see it in the list below, please put together a proposal before spring break and I'll see if we can do it later in the semester.
Gamma Ray Absorption: Absorption of gamma rays by material is an exponential process. (I may have you guys to this one too!)
Lab Book pages: I got a little carried away with fitting stuff.
Lab Report: A brief note on what we did, what happened and what to do next.
Lab Report: A brief note on what we did in 2007.
Excel Example in .xls file of the 2006 Collimated data: You can modify this file and fit data that you have to a straight line. Be sure that you do modify and pay attantion to what you are doing. Here is the Un-Collimated excel file.
2008 Data and notes Data and notes on what we did in 2008.
2008 Data and notes Rough graph with what we did in 2008.
Intro to Statistics
Notes: Some of this I skipped in class cause you guys said you were familiar with a gaussian and counting statistics.
Poisson and Gaussian Distributions
Gaussian Behavior of random sum
Intro to fitting and parameter determination
Notes : This has the correlated errors and the gory math details of the fit to a straight line taking errors on y into account.
Next, I rebin some exponentially distributed data, take the natural log of the bin entries and fit the data with a method described in class. On the first page, I show a fit to the exponentail using a sophisticated fitting program. The next page down has the example using the technique from the notes and from the class discussion we had on the exponential decay. This is a very useful technique!
Example of fitting to Exponential Decay Data
Data used in fit example.Powerful and Free analysis and fitting package (PAW) Intro to Physics "spreadsheeting" with PAW
Other Web pages to check out: (Note: this is the official class web site.)
Vanderbilt Safety Page Lots of info on Doctors and patients. Have to dig for pertinent info.
Prof. Webster's page of 225 labs and info
My old 225b course and info page (There are worked homework problems here!)
Thanks, w.j.