PHYSICS 387/388/389/506  

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In the lab

Experiments and writeups

Photoelectric effect
questions supplement
Melissinos notes on PE
A.N James  on the PE effect
PE effect and Historical burdens
X - rays
Important:You will need to obtain a radiation badge (see instructions). It takes several weeks to arrive, so plan ahead. 
Electromagnetic boundary conditions
Background information
Gamma ray spectroscopy-


Note: You wil not need a radiation badge for this experiment
Zeeman effect
questions SynerJY data-collection  manual
atomic spectra
Zeeman effect background
Speed of light questions
Franck Hertz
Equipment and procedure

Pulsed NMR

questions Oscilloscope manual
Pulsed and continuous wave NMR
Further reading
Raman Scattering
You must read the sections on safety procedure in this laser manual before starting experiment.
Faraday effect
CYCLOTRON  Research project

Overview of cyclotron

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An important objective of this course is to instill habits of record keeping that will serve you well in future research. A good laboratory notebook is essential when you begin to write papers or to develop oral presentations summarizing your experimental efforts. A clear well-written narrative that includes experimental schematics, plots of raw data, and details of your analysis methods will enable you to receive quick feedback and assistance during lab sessions.
You will be given a standard experimental notebook in which the complete dated record of procedures, events, original data, calculations and results of every experiment is to be kept. Although you will work in a group and are urged to collaborate on all aspects of the experiments, each student must keep a complete, dated record of each experiment and its analysis. High resolution plots, photos, and Xerox copies of shared data should be glued or taped in place.
Your notebook will be checked during class times several times a semester.

The following is a list of record keeping guidelines to follow when performing laboratory work.
Create a descriptive table of contents and make an entry every time you add new material.Title the TOC with the following: Date - Contents - Page. Don't use generic entries like "Day 1" or "Analysis". Instead, produce records of signifcant mile stones: e.g. "Calibration of NaI Scintillation Counter Using Ba-133 and Na-22 Check Sources",
  •  Don't erase, use white-out, or tear out pages of a lab notebook. Indicate \mistakes" by simply drawing a single, neat line through the item. These may prove  not so incorrect as initially thought and will very often be useful as a guide to how the experiment was done and provide clues on how to better execute the experiment next time.
  •  Loose-leaf pages are not acceptable within a lab notebook. Graphics or tables generated by computer must be neatly taped into the notebook. Remember to annotate these types of graphics with as much information about how they were created as possible.
  • Your notebook should contain diagrams, narratives, tables of raw data, formulas, computations, reduced data, error analysis and conclusions in a neat compact, orderly arrangement.
  • Bring your notebook to every lab session. Failure to do so will result in penalties to your grade.

  • Notebook grading criteria

    In-class notes
    • Notes are original, in-class notes.
    • Notes are easy to follow: an outsider could tell what was being recorded and why.
    • Notes are complete: operations or conditions that affect the interpretation or analysis of data are given.
    • First page includes name of experiment, names of all partners, and dates beginning and ending
    • Notes are neatly kept and are recorded in pen.

    Apparatus diagrams and annotations
    • The diagrams + annotations succeed in communicating how the apparatus works and how it was used.
    • Diagrams are functionally clear: the diagrams would make sense to other students in the course.
    • Diagrams are correct and well annotated, indicating the use and/or function of each important
    component and sub-component, clear signal paths, and important physical features (e.g. magnet
    orientation, important dimensions).
    • Diagrams are original drawings taken from the apparatus itself, not merely copied from the
    • Raw data are correct: no significant mistakes in collection of data.
    • The data set is sufficient to calculate all important results and random uncertainty.
    • Relevant conditions pertaining to data sets (e.g., sample type, run number, equipment settings) are present.
    • Tables of data include an estimate of uncertainty along with reasons for assigning that uncertainty.
    • Raw data are recorded neatly, with correct units.
    • Copies of original data (XY plots, computer printouts, tables, etc.) are complete and annotated with information describing the sample, conditions or other information pertaining to it.
Preliminary Analysis and Results
Data analysis
• All classes of data taken have at least one set analyzed. [All data sets must be analyzed in final report.]
• Analysis of data is correct, with correct units.
• Plotting and fitting of data to obtain results is used when appropriate.
• All calculations performed,  are fully and clearly described with annotations. [Any computer code must be included in final report.]
• Graphs are at least 1/2 page in size and easy to read: one could estimate data points from the graph
• Graphs follow these basic formatting conventions: Legends are given for graphs with multiple data
sets and/or curves; data points are bare—point symbols not connected with lines; when applicable
points include error bars; theoretical curves and/or fits are shown as lines (not points); axes are
labeled with quantity and correct units; there is a clear title explaining the graph’s purpose.
• Spreadsheet printouts are clearly laid out with labeled columns and rows, including quantities and
Uncertainty analysis and calculation
• Uncertainty is calculated for numerical results for at least one data set in each class of data. [full calculation to
be included in final report].
• Reasoning and method used to derive uncertainty in final results is clearly presented and correctly
• Uncertainty calculations themselves are clearly shown (either in entirety or with examples).

  • Preparing for an experiment
o     Prior to each new experiment read the experimental  writeup thoroughly in order to understand the physics involved.  Do not start an experiment before understanding the entire procedure.
o    Preparatory questions. Each lab guide includes a set of preparatory questions which point you to the essentials of the experiment. Work out the solutions to these problems in your lab book before starting the experiment.  Make a copy of your solutions and hand to the TA no later than the beginning of the second session. Late solutions will not be accepted because you will need to know this material BEFORE the experiment.
o    Summary of objectives and procedures. The next entry in your lab book should be a statement in your own words of the essential physics ideas and principles of the experiment. List your experimental objectives and how they relate to the essential physics.  After listing the objectives, identify the things you will have to do, the data you must obtain and identify the required calibrations.
  • In the lab
o   Your laboratory  notebook  should be with you at all times and used to keep a record of every step of the experiment.  It must contain sufficient narrative as the experiment proceeds so that, years later, you could reproduce the results you obtained. Notes, tables, and graphs should be neat and compact, leaving as little empty space in the lab notebook as is compatible with clarity and the logic of organization. There should be no loose sheets or graphs in your notebook.
o   On the first day of a new experiment, before turning on any of piece of equipment, read the manual and familiarize yourself with the controls and operation.  The relevant manuals will be placed  near each experiment. If you cannot find a manual ask the course assitant to help you find it.
o   When you feel confident you understand the equipment and the measurement procedure hook up the experiment according to the diagram  described in the lab writeup and turn on the the equipment.
o   At this point sketch a block diagram of the apparatus and signal chain in your lab notebook.
o    Note typical “readings" and instrumental settings so as to be able to quickly setup an experiment on subsequent days.
o    Sketch waveforms at various places within the signal chain. This will help ensure your understanding of each component and permit you to rapidly identify equipment failure.
o  When tabulating data into columns, use headings and list the units and estimated measurement uncertainties.
o    Don't wait until after the session has ended to visually examine the quality of your  data. Create hand drawn plots of data, as they are acquired, not later. These initial plots will save you time and frustration in making sure that your data are reasonable and suggestive of the behavior you expect. Analyze data in the lab in a preliminary way as you go along to check for reasonableness. If you are making a series of measurements of one quantity as you vary another, plot the results as you go along so that you can see the trend, catch blunders, and judge where you may need more or less data. Repeat every measurement at least five times in as independent a manner as possible in order to establish a statistical basis for estimating random error and to reduce the chance of blunders. If you get through all the manipulations and preliminary analysis of an experiment in less than the alloted time, take the opportunity to perfect part or all of the experiment so as to obtain the best possible data set.
o    Some experiments will require you to transfer your data to a computer and store them in files on disk. Obviously, it is not practical in these cases to print out all your data and paste them into your notebook. However, your lab notebook should include a clear description and summary of the data files so that when you return to them days or weeks later, you are able to identify particular files with procedures you carried out in the lab. Identify the location of large data files or long analysis programs if they are too big to directly enter or tape into your notebook. Analysis scripts, functional forms for non-linear fits, etc. should always be present in your notebooks.
o    Your notebook will be checked and graded  during class.
o   As a courtesy to the next group leave your work area at least as tidy as you found it. Return reference material and tools at the end of each lab.
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Computational resources

We have several Windows XP machines in the lab with data analysis programs including Origin  (the manual  can be downloaded here  an example can be found here) Kaleidograph and  Excel (an example can be found here). Mat lab can be found on Rutgers machines in most  computer labs.
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Lab Reports


The lab report should show mastery of the entire experiment, and possess a neat appearance with concise and correct English. Length should be ~ 3200 words (excluding the title page  bibliography and supplementary information in appendix ).  This corresponds to   ~ 8 pages  with double spacing and 12 pt font. (If you wish, you may attach data sheets for your own records.)  Alternative if you chose PRL or Nature format it should be ~ 4 pages (two column 10pt font and single spaced).
 For publication style reports you may use  a Word or  Latex template.
If using  Latex you will need this template file. To insert figures you will need  figure files as in this example and for citations you will use a  bibliography file as this one.  To compile the file use Revtex 4.1
Also there exist collaborative Latex tools such as Write latex ( ) that allows a group to edit and compile a single document online similar to google docs.

The report should consist of the following elements:
I. Abstract
II. Introduction (purpose, equations; 1 ~ 2 paragraphs)
III. Apparatus (1 paragraph of description)
IV. Data (pages from the student's lab notebook)
V. Analysis and Results (graphs, calculations, answers)
VI. Discussion (measurement uncertainties) and Conclusions
VII Bibliography

ABSTRACT should appear on the title page. This is part of title page of the report, but it is a good idea to write it last, when you know exactly what you are summarizing. The abstract is a concise summary of what the reader will find in the paper. It should briefly mention the motivation, the method and most important, the quantitative result with errors.  Based on those, a conclusion may be drawn.  You should use appropriate technical terms, leaving their definitions and explanations for the Introduction.

INTRODUCTION OR BACKGROUND.  Desctibe briefly what the experiment is about: Give some historical context, but not many pages or long quotations. Outline theoretical results which will be needed, but omit intermediate steps of derivations; you don't have to tell everything you know. Be sure to define all terms appearing in formulas.  Material and ideas drawn from the work of others must be properly cited in the bibliography.

APPARATUS AND PROCEDURE. This section describes the main components of the apparatus. It makes reference to a figure(s) which contains a diagram  of the apparatus and includes the most important signal processing steps. The figure should be referenced as early as possible in this section with the placement of the figure as close to the descriptive text as is possible. This should be followed by a description of the procedures and of the measurements.

DATA. Give a narrative, which cites data in tables and graphs. All figures and tables should be numbered, and should have captions.  Make  sure that axes are labeled, with units. The text should tie everything together in a linear sequence. Therefore all Tables, Figures, and Graphs should be cited by number at an appropriate place in the text. Place Figures, Graphs, and Tables in the text as close as possible to where they are cited (rather than at the end of the report). Do not inundate the reader with material; you should find a way to summarize your results in  two or three plots or tables.

ANALYSIS  Compute from your data whatever quantities are most appropriate for making comparison with theory, or for extracting useful information. Where repetitive calculations are necessary, present one sample calculation to make the procedure clear. Be sure to include a precision (i.e., "error" analysis), which starts from estimates of the uncertainties of the measured quantities and leads to an estimate of the precision in the final quantity derived [See any of the references on statistics and error analysis]. Remember that the crux of the report is how much you can get out of your measurements and how reliable the results are.

CONCLUSIONS. State the main results, but omit vague generalities. List and discuss possible causes of any discrepancies between your experiment and theory or previous measurements; bring your estimate of precision into the discussion. You might suggest specific improvements of the experiment.

BIBLIOGRAPHY. In  this section which should be after the  last page list all references used, whether explicitly cited in the text or not. Use citations throughout the paper to acknowledge sources. These citations may be by number or by author.

Comments .
It may be useful to model your reports on Nature letters or  Physical Review Letters (some copies are reserved in the lab).

Reports will be graded using the following criteria:
1. Theoretical and/or Experimental Motivation - 15%
2. Description of Experiment - 15%
3. Data presentation and  Analysis  - 40%
4. Conclusions and answers to questions 20%
5. Style and English - 10%
6. A 4% deduction will be assessed for EACH day the report is late.

Tutorials on  basic measurement apparatus

References on Statistics and Error analysis
Prevention of injury is a matter of being aware of  pieces of equipment that are potentially dangerous. Since it is virtually impossible to set up a reasonably comprehensive and interesting set of experiments in modern physics without using equipment which has potential hazards, it is essential to be aware of the hazards, and exercise appropriate precautions.
 Electrical Safety
The first rule is never to work alone. All high voltage supplies are clearly marked as dangerous. Do not poke or probe into them. Turn off the supply if you need to change cable connections. The supply may be dangerous even when turned off if the capacitors have not discharged; always keep one hand in your pocket when testing any circuit in which there may be high voltages present so that if you get a shock, it will notbe across your chest. Never go barefoot in the lab. Remember that it is current that kills. A good (e.g. sweaty) connection of 6 volts across your body can kill as well as a poor connection of 600 or 6000 volts.
 Laser Safety
A laser beam may not seem very bright, but if it enters your eye it will be focused by the lens of your eye to a pinpoint spot on the retina where the intensity is sufficient to destroy retinal cells. It is wise to terminate a laser beam with a diffuse absorber so that the beam doesn’t shine around the room. Never examine the performance of an optical system with a laser by viewing the beam directly with your eye or reflector.
Radiation Safety - link to power point presentation
Ionizing radiation damages tissue; any exposure should therefore be minimized. The unit of radiation exposure is the rem (roentgen equivalent man). Your inescapable dosage from cosmic rays and other background sources is 360 mrem yr−1, which works out to 4.2 x 10−2 mrem hr−1. The recommended limit to controllable exposure for a member of the general public is 100 mrem yr−1, averaged over any consecutive five years. If you follow the  Lab guidelines, your exposure will be only a small fraction of the dose you receive from the natural background.
Radioactive sources emit three types of radiation: high energy helium nuclei (alpha rays), electrons (beta rays), or photons (gamma rays). Most of the sources in the Modern Physics Lab emit only gamma radiation.
 The strength of a radioactive source is measured in curies (Ci). A one-curie source has an activity of 3.7 x 1010 disintegrations s−1. The “absorbed doseâ€� is a quantity that measures the total energy absorbed per unit mass; it is measured in rads, where 1 rad = 100 erg g−1. The “equivalent doseâ€� is measured in the units discussed above, the rem. The equivalent dose is derived from the absorbed dose by multiplying by a “radiation weighting factorâ€� which is a measure of how damaging a particular type of radiation is to biological tissue. For photons (gamma rays) and electrons and positrons (beta particles), the radiation weighting factor is unity; for helium nuclei (alpha particles), it is 20; for protons with energy greater than 2 Mev it is 5; and for neutrons it ranges from 5 to 20, depending on the energy. When you use the meter in the lab, the readings are in rads, and you must consider the type of particle when you work out the equivalent dose.
For gamma rays with energy greater than 1 MeV, a useful approximation is that the equivalent dose due to a source with an activity of C microcuries is 5.2 x 10−4CE R−2 mrem hr−1, where R is the distance from the source in meters and E  is the energy of the gamma ray in MeV. For gamma rays with energy less than 1 MeV, this formula is still approximately true for a full body dose. However, low-energy gamma rays deposit their energy in a smaller mass of tissue than high-energy gamma rays and can cause high local doses. For example, the local dose to the hands from handling a 10 keV source can be up to 25 times the value given by the above formula; hands, however, have a higher tolerance to radiation
than inner organs or eyes.
The protective value of shielding varies drastically with the energy of the photons. The intensity of a “soft� Xray beam of < 1 keV can be reduced by many orders of magnitude with a millimeter of aluminum while 1.2 MeVgamma rays from 60Co are attenuated by only a factor of 2 by a lead sheet one-half of an inch thick. The best
way to keep your dosage down is to put distance between you and the source. If you stay a meter away from most sources in the Lab, you will be receiving, even without any lead shielding, a dose which is much less than your allowable background dose. If, however, you sit reading the write-up with a box of sources a few inches away, you may momentarily be receiving ten to a hundred times the background level.

Precautions for Working with Radioactive
Materials - ALARA
1. Don’t handle radioactive sources any more than you have to.
2. Work quickly when transferring or positioning radioactive sources.
3. Never take a source out of the  Lab, even temporarily.
4. Keep sources away from your body.
5. Be aware of the sources being used in neighboring experiments.
6. Remember ALARA – As Low as Reasonably Achievable!
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 A tutorial on writin g Powerpoint presentations can be downloaded here.
 At the end of the term, each student will give a public oral presentation which will be attended by all students in the section. The presentations should be  in the style of a paper presented at a conference. Questions from classmates are encouraged allowing for a general discussion of the experiment.


  1. The presentation should be about your fourth experiment, unless a substitution is agreed upon with the instructor.
  2. All students should attend the whole session, and participate in asking questions.
  3. Each lab partner will have 12-15 minutes to make a presentation, with a few minutes after each part for questions (such as requesting clarification). There will be time for questions addressed to either partner after their talks. Partners should decide between themselves how  to divide the material (Background, theory, apparatus, procedure, data, analysis, conclusions, etc.). However, each should give a single segment.
  4. The talk should be prepared for a powerpoint presentation. It should include title page, outline of talk, graphs, diagrams, summary of conclusions, etc.. Do not include extensive text or long derivations of equations, but just outlines, final equations, or a few sentences of conclusions. The blackboard is also available.
  5. Practice the talks with your lab partners. In addition to refining the presentation, checking the length, and making sure nothing crucial falls through the cracks, try to anticipate questions which may be raised.
  6. Each student should ask at least two questions (overall) of other speakers (besides lab partner). These should not be confrontational, but seek clarification of surprising, intriguing, or unclear points in the presentation.
  7. Useful links and examples

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