205 sp11 lab prac-proc

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LABORATORY POLICIES, PRACTICES AND PROCEDURES

FOR THE

NUCLEAR ENGINEERING GRADUATE AND UNDERGRADUATELABORATORIES

SPRING 2011

School of Nuclear EngineeringPurdue University

West Lafayette, IN 47907


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NUCL 205 Laboratory Procedures i 11 January 2011

TABLE OF CONTENTS

INTRODUCTION ....................................................................................................... 3

COURSE FORMAT ................................................................................................... 3

LABORATORY PRACTICES .................................................................................... 4

LABORATORY RULES ............................................................................................ 5

LABORATORY POLICIES ........................................................................................ 5

LAB NOTEBOOK DETAILS AND FORMAT............................................................. 6

APPENDIX A: SIGNIFICANT FIGURES ................................................................ 12

APPENDIX B: Some Guidelines for Making Acceptable Scientific and

Technical Graphs ................................................................................................... 14

APPENDIX C: STEPS TO FINDING A TRACE AND SIGNAL OF INTEREST ON

AN OSCILLOSCOPE (Tektronix-Analog) ............................................................. 19APPENDIX D: Finding a Trace and the Signal of Interest on a Digital

Oscilloscope........................................................................................................... 20


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NUCL 205 Laboratory Procedures ii 11 January 2011

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NE Laboratory Procedures 3 11 January 2011

INTRODUCTION

The objective of this course is to introduce the concepts of the properties of radiation and

radioactive materials, radiation detection and measurement, and emphasize the safe handling of

radioactive materials. The course will also develop good laboratory practice, including proper

methods of data collection and analysis. The scope of Nuclear Engineering is very large; we can

only hope to give you some basics so that you may get a feel for the subject and laboratory

practice.

At the start of the semester in 205, we assume you have only a vague idea of the physics

behind many of the phenomenon associated with nuclear engineering. So we will try to hit the high

points, at least the things we feel are the most important. Along with the high points, we must also

hit the things that allow us to progress to the senior year. About half of the sophomore semester

could be considered laboratory technique, or how to collect, reduce and interpret data; in fact one

student was overheard to say at some point beyond mid-semester that now we start to do true

experiments.

Nuclear Engineering has had a lab class series from the inception of the school. The form and

material evolved for about 10 years, then the lab goals and direction of the lab classes settled more

or less into the current arrangement around the mid seventies. Experiments have been updated to

reflect the changing technology, but the methodology has remained fairly consistent. There was

once more material covered in the class, such as a computer programming assignment per week in

NUCL 205, but this has been dropped from the course.

Comments about the equipment:

The equipment that you see in the laboratory; although research grade; is not in general the

same equipment you will see in a Nuclear Power Plant control room. This equipment has been

chosen to allow you to get a good feel for the modular approach to any system to which you might

be exposed. Then if you see a box doing a function, such as controlling temperature, you may

assume that some part of the equipment has a sensor or detector, cabling, a setpoint and some

method of feedback. If you see a system doing radiation counting you might assume cabling, a

detector, preamplifier, amplifier, some form of bias supply etc.

COURSE FORMAT

This course consists of one fifty minute lecture and a two hour scheduled laboratory period per

week. Ideally, all theory and material pertaining to a given experiment is covered in lecture prior to

the experiment; however, this is not always possible due to equipment constraints. Therefore, you

should plan to read ahead in the associated references listed for the experiment you are to perform

for a particular week, in addition to whatever reading assignments are provided for the lecture in aparticular week.

Nearly all of the experiments performed in this class can be easily performed in the allotted time

period, provided proper preparation (thats a lot of alliteration) has been done prior to the lab. It will

be necessary to remain in the lab until you have completed all of the work. Again, being prepared

before you come to lab will prevent most time issues.


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The following information is provided as requirements and guidelines for your use in taking this

class. The policies are for safety of personnel and equipment, and for courtesy to your fellow

classmates (i.e. lab partners), and for personal accountability. The procedures are provided to

point out a way to get through this class with a minimum of pain and suffering, and an effort to help

you produce your best work. There is also information about some of the lab equipment in the

appendices to help you out as needed, as well as tips for proper data presentation.

LABORATORY PRACTICES

The necessity for safety precautions and approved procedures exist because of the unique

nature of radioactivity. Man has no physical sense for the detection of radiation and the physical

effects of radiation are not immediately evident. Radioactive contamination may be spread

unwittingly. The intent of the safety precautions is to develop safe practices that will aid you in your

professional life. Violations of the rules cannot be tolerated. More cautious practices may be

followed if desirednever less. In general, the following rules will apply to radioactive materials

used in this laboratory.

1. Radioactive sources and materials will be handled with the tools provided.

2. Sources are to be kept away from the body at a distance equal to the length of the handling

tool.

3. Avoid unnecessary exposure at all times (operate under the principals of ALARA).

4. Survey the area if any doubt exists as to the radiation level. Be sure the survey instrument

will detect the type and energy of the suspected radiation.

5. If there is a spill of radioactive material, protect the area from being entered by others.

Report the spill immediately to your instructor. An unreported spill may cause potential harm

and great inconvenience to all concerned. Survey the area, shoes, clothing, hands, etc.

6. Personal monitoring will be by dosimeter, which will be worn by each student participating in

the laboratory session. If you forget to sign in the dosimeter at the end of the laboratory

period, return it no later than noon the next day.

7. Cleanliness is absolute. Radioactive contamination is spread by poor housekeeping.

Laboratory equipment, tools, etc. are to be cleaned after use and returned to the proper

storage location.

Complete information about the federal laws governing the use of radioactive materials in 10

CFR 20, which is available on the website: http://www.nrc.gov/reading-rm/doc-

collections/cfr/part020/. The Purdue University policies are presented in the Radiological Safety

Manual, which is available on Radiological and Environmental Managements website:

http://www.purdue.edu/REM/home/booklets/radman.pdf.


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LABORATORY RULES

The following rules apply to the laboratory and surrounding areas. They are for your safety and

the safety of your classmates.

1. NO SMOKING, DRINKING OR EATING IN THE LABORATORIES. This includes coffee

and carbonated drinks, candy or gum. (Eating is permitted in the shop and hallway.) Thisalso includes application of Chapstick or other lip stuff.

2. The laboratories are to be restored to a neat and orderly condition after the laboratory

experiments are finished. All equipment is to be returned to its proper place, all power cords

unplugged unless otherwise specified, all chairs/stools put under the benches, etc.

3. Debris are to be deposited immediately in suitable containers. If the waste is suspected of

being contaminated with radioactive material, ask the lab instructor for disposal directions.

4. Equipment will not be removed from the laboratories without the expressed permission of

the instructor.

5. No visiting friends. They may distract you from your work and they do not know thelaboratory rules and may violate them.

6. Proper attire is required. No open shoes (e.g. sandals, flip flops) are allowed. Shorts are

allowed with the exception of one experiment, of which your instructor will inform you.

These rules may be changed or amended as the situation demands. If you have any doubts,

consult your instructors. Violations cannot be tolerated.

LABORATORY POLICIES

All students are expected to have read the reading assignments for the experiment being

performed before coming to the laboratory. Short quizzes may be given at the beginning of each

lab period covering the material from the laboratory handout, information about the experiment orset-up, or over material from the reading assignments.

Laboratory attendance is compulsory. If you miss an experiment, you may not use your

partners data to write a lab report. You will need to arrange with the laboratory instructor to make

up the experiment. Valid reasons for late reports and makeup experiments will be restricted to

incidents (such as broken legs) that are generally accepted for missing a day or more of class

attendance or a major exam. If you miss an experiment without a valid excuse, your score on your

report will be reduced by 20% after you make up the experiment. Availability of laboratory time and

instructors to supervise your making up the experiment is limited, so it is best to not miss a

scheduled lab period. The standard late policy will still apply for labs made up after unexcused

absences, i.e. the lab write-up will be due in the following regularly scheduled lab period.

For the majority of the experiments, lab partners will be shuffled such that you will not work with

the same person twice. If equipment constraints require rotation of experiments, lab partners will

then remain the same for the duration of the rotation schedule.

Laboratory data are to be kept in bound notebooks with carbon copies made of all entries. The

carbon copy is to be turned in as the lab report for grading. The original will be kept as a

permanent record and for references. You will also be expected to refer to previous experiments


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for information, so it is often a good idea to have your older notebooks that contain related

experiments in lab with you.

Laboratory reports are due prior to the start of the lab period immediately following the one

when the experiment was performed, e.g. if you performed an experiment on Tuesday the 12th, the

report is due at the beginning of your lab period on the 19th. Any reports turned in later than the

beginning of the lab period will be recorded as late. Late labs will be assessed a 50% penalty. forthose labs turned in the close of business the day following the due date. Late reports must be

turned in to the receptionist in NUCL 140, where they must be time stamped. Any reports not

turned in by the close of business (5 PM) the following day will be recorded as a zero. If you do not

get the time stamped on the report, we cannot know when you actually turned it in and you may

lose more points than necessary.

All reports must be turned in to pass the class. At the end of the semester, a grade of

incomplete will be given if one lab report is missing due to a valid reason. Otherwise, missing

reports will result in a course grade of F, independent of your performance on the exams and on the

reports which were completed. The lowest lab report score will be dropped from the final grade

calculations.

LAB NOTEBOOK DETAILS AND FORMAT

As stated before, laboratory data and write-ups are to be done in bound notebooks with carbon

copies. This necessitates doing all of the work by hand, which is the proper method for data

collection and evaluation. The purpose of this is to produce a proper record that can be later used

by either yourself or someone else to reproduce your work. Thus, computers will only be used for

data analysis and plotting where appropriate. The target for your laboratory reports is to produce

what could be used as a legal document in court, if necessary (e.g. in a patent case), or as a way

for someone else to recreate what you have done without any other documentation (reproducibility).

Therefore, proper reporting methods are required.

Different institutions or organizations will have their own style requirements for lab notebooks,

the specifics of which may vary greatly, but the general theme of the styles will be similar. You may

consider this a tyrannical approach to be so stringent on formatting and style, but the instructor is a

benevolent tyrant, and is only looking out for your best interest.

Do not hesitate to record original data directly in the notebook. This is standard practice, and is

compulsory everywhere. If you should (perish the thought) make a mistake, simply draw a single

line through it and continue. Each page should be sequentially numbered, and the original pages of

the notebook should not be removed. Each page should also have a brief title block, with the

experiment title, lab partner and date of the work at the top, such that it is obvious to anyone looking

at the page that it belongs there.

Everything that is done should be described in the notebook such that it would be clear to areader what procedure was followed, how the equipment was set up, how the data was collected,

etc. Again, the goal is to provide for reproducibility from your report. Anything that could have an

effect on your data should also be described in your notebook, such as if the lights flicker, you

bump a control or plug, etc.

Prior to coming to the lab, you should have read the lab handout thoroughly. Pertinent

background information is provided in the introduction, which will give you a better understanding of


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the experimental procedures and apparatus. Being familiar with the procedure before coming to the

laboratory will make your time there more efficient. Also, you may wish to pre-prepare some tables

in Excel or a similar program to assist you in your data analysis, some of which must be completed

before you leave the laboratory.

Your lab work will be submitted in two parts: The first part will include the pre-lab, and the work

you do in lab (data collection and preliminary analysis). The second part will be your data analysis,error analysis, conclusions and references. The pre-lab and data collection/preliminary analysis will

be turned in at the end of lab, the second part will be turned in before the beginning of the following

lab period.


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TABLE 1: LAB REPORT PART 1 REQUIREMENTS

The following should be completed before you come to the laboratory, and may be checked.

Title Block:

Goals:

The title block should contain the title of the experiment, the experiment number,your name and your lab section, the date and time the experiment is performed,

and the date and time the report is due. This should only take up about of thefirst page.

Summarize the objective of the experiments in your own words; this should not bea copy of the lab handout.

Theory:

Equations:

Decay Schemes:

Brief discussion of the theory behind the method and analysis of the experiment.(


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TABLE 2: LAB REPORT PART 2 REQUIREMENTS

The following work can be performed after the lab (but it is advised that you do what you can in labif you have the time.) This remainder of the report will be turned in BEFORE the start of the nextregularly scheduled lab class.

Data Analysis and ErrorAnalysis

Include the data, your manipulation of the data, describe the data and why youmanipulated it a certain way, include the major values you measureddetermined and compare to published numbers (cite references), and analyzewhat it means

Conclusion Restate the purpose of the experiment, summarize your results, what themeaning of your results is, make some remarks about your error, and anythingelse that might be of interest. Be concise but thorough.

Questions Answer the questions (if there are any) at the end of the write-up

Lab report points assignment:

Title Block, Exec Summary 5

Goals/Short Theory/Eqns/decay sch 10

Summary of Planned Proc. 5

In-lab procedure/data collection 20

Data analysis 20

Error Analysis 10

Graphs/Tables/O-scope drawings 10

Format 5

Conclusions 10

Questions 5

100

Here are some helpful tips on things to do or make sure that you include in your reports to get a

good grade:

Each page, except for the first because it has the title block, should have the experimentnumber, the date, the name of the experimenter (you).

Make sure you read through the questions for each section. If you have them in mind while

you are doing the experiment, you will be better able to successfully answer them as you work

through the procedures.


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If you intend to use a spreadsheet program to help with your data analysis, it is often helpful

and will save you time in the laboratory if you have set the worksheet up before coming to the

lab.

Include diagrams of all physical layouts of equipment, including dimensions, if they are

important.

Drawings of the oscilloscope pulses for all of the pieces of equipment that have a signal

output pulse, drawn as you add them to the counting/analysis system (i.e. each time you hook

something up, draw the output pulse for that component.) There will be experiments where

you will be directed to draw additional pulses when certain parameters are changed. Make

sure to include all necessary information on your drawings, and they are of a size that is easy

to read.

When data is repeated, with only one or two of the parameters changed, it is best to make a

table of the data, recording it by hand (the data can also be entered into Excel at the same

time, but should still be recorded by hand, therefore your collected data is secure from

everything but you losing your notebook, or your dog eating it, or your roommate using it for

toilet paper, etc.)

Note when anything out of the ordinary happens (lights flickering, bumped equipment, etc.)

next to the datum where it occurred. These events can often be correlated to bad data

points, and the points can be repeated at that time and both points recorded.

Be clear but concise in writing out your steps in equipment set-up and data collection. Your

goal is, again, reproducibility, with the reader using only your lab report and nothing else for

direction. In other words, dont just have data appear without description of how you obtained

it (reproducibility, reproducibility, reproducibility). Track your connections, equipment set-ups,

times, settings, etc. You arent writing a novel, but everything you do should be clear to the

reader.

Plot your data as you record it (Good experimenters continually note trends in data.) The

easiest way to detect trends in data or any changes in the trends is by looking at plots. When

bad data points are observed, they can again be quickly repeated without losing much

valuable time.

If you use Excel or some other spreadsheet or graphing program, first carry out the

calculations done for the first one or two data points by hand to verify that your formulae are

correct in your spread sheet. Then all spreadsheet tables and plots are to be cut out and

glued onto both the original and carbon copy of your lab notebook. Make sure you have all

plots and tables labeled appropriately, such that the origin and content of the data are clear to

the reader. Unless specifically permitted by your instructor, any sheets stapled within or to the

back of your lab reports will be removed and not counted with graded material. The continuityof the numbered pages is important. The above rules apply to MCA output as well.

Write down EVERYTHING in your notebook, including all scratch work, and any

interpretations necessary for evaluation of data. Any scrap paper or notes external to your lab

notebook will be destroyed by the instructors. Dont rely on your memory, write it down. If you

have forgotten your notebook, dont bother coming to the lab. Your experiment will have to be

made-up at a later time with appropriate penalties for late reports.


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If questions are included in the procedure, make sure you answer them as you go, and not at

the end. The questions within the procedure are intended to help you understand what you

are doing while you are doing it.


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APPENDIX A: SIGNIFICANT FIGURES

There is a strong tendency for students to confuse the number of digits in a number and the

precision and/or accuracy of a measurement or calculation. The number ofsignificant digits in a

number is an expression of the accuracy of that number. If the results of a measurement are

accurate to only 1% then no more than 2 or 3 significant digits should be used when reporting the

results of the measurement. Therefore, when writing or reporting a number, care should be taken

to use only the number of digits that are meaningful. Although the complete treatment of significant

numbers is complicated and based on the precision and accuracy of the measurements or

calculations, the following simple rules are sufficient for most cases:

Rule 1: Number of significant figures

In a measurement, the exact known digits plus the first estimated or doubtful digit are called

significant figures. Zeros that are used for locating the decimal point are not significant figures.

Thus, the following numbers all have four significant figures:

4739, 4.739, 0.004739, 5001, 5.100, and 57410.

The last number can be confusing and there is no agreement on whether this zero is for locating

the decimal point or represents a significant number. The best way to resolve the situation would

be to write the number in scientific notation, i.e., 5.741 x 104 if there are only four significant figures

or 5.7410 x 104 if there are five significant figures.

Rule 2: Round off

Two procedures are in common use for rounding off numbers when digits are to be dropped.

The most common technique is to leave the preceding digit the same if the first digit to be dropped

is less than five and to increase the preceding digit by one if the first digit to be dropped is 5 or

greater. Thus, 27.642 becomes 27.64 and 27.645 becomes 27.65.

A second procedure that is gaining in popularity states that if the first digit to be dropped is 5,

the preceding digit is rounded to an even number, that is

27.642 becomes 27.64

27.646 becomes 27.65, while

27.635 becomes 27.64, and

27.625 becomes 27.62.

Currently, no preference is given to one system or the other and in this course the choice of

methods will be left to the student. However, only one system should be used at a time to avoid

confusion.

Rule 3: Significant figures when adding or subtracting numbers

In addition or subtraction, there should be only as many figures to the right of the decimal point

as there are in the number having the fewest such figures. That is all columns of digits to the right

of the first column having a doubtful digit are eliminated and the numbers rounded before making

the addition or subtraction. For example:

49.350 becomes 49.35


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54.32 54.32

+ 4.786 + 4.79

108.46

Rule 4: Significant figures when multiplying or dividing.

In multiplication or division, retain in the answer the same number of significant digits as in the

least accurately known quantity. Thus,

34.84 x 2.6 = 91, not 90.584

since 2.6 has only two significant figures and, in fact, has an uncertainty of one part in 26 or

approximately 4%. Therefore, the result should also have an uncertainty of about 4% or about four

parts in 91 and writing the answer as 91 actually overstates the degree of confidence that should be

placed on it.


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APPENDIX B: Some Guidelines for Making Acceptable Scientific and TechnicalGraphs

One goal of presenting experimental data graphically is to provide a way to present the results

of experimental measurements in such a way as to show how a measured variable relates to an

independent variable. The experimenter or reader can then more easily evaluate the information

being presented, and make some determinations or assumptions about the material presented.

Before you make your plot, keep the following questions in mind and this will help you choose :

What are you trying to show or identify?

Should the data fit some physical function or relation?

Axes, Scales and Units

First, choose what variables you will plot on the x (abscissa) and y (ordinate) axes. Typicallythe independent variable (the one the experimenter controls) is plotted along the x-axis, andthe dependent variable (measured) is plotted along the y-axis.

Each axis should be properly labeled, including the proper units (usually in parentheses),e.g. an x-axis label might read: Bias Voltage (V), and a y-axis label might read: CountRate (cts/60s).

When choosing the range of the axes, understand the details of the data that are to bepresented. The axes to not have to start at zero, and this may allow more detail to be seenin the distribution of the data, but it may not be the best choice to zoom in on the data,particularly if you are trying to show that the data do not vary that much.

It is traditional to have the values of the scale tick marks be divisible by 1, 2, or 5 times somepower of 10. For example, division values of 50 cts/60s or 100 V are acceptable, but 30 V isnot.

Some more considerations

When choosing the best way to analyze the data graphically, it is important to consider

the accuracy of the data fitting. If you are performing your analysis manually (by hand), the

only fit that can be reliably done is a straight-line fit. This will necessitate that your plot your

data such that you expect the data to line up. This can be achieved by changing the

variables on the graph. For example, if you are attempting to determine the decay constant

for a radioactive isotope, , you may measure count rates, which would follow the function:

N=Noe-t. Since performing a fit of an exponential manually would be virtually impossible,

you could perform an additional operation and easily find by plotting ln(CR) vs. time. Most

computer plotting packages presently available have relatively sophisticated fitting toolkits

able fit many standard functions to plotted data. However, you should know the limitations

of the program before making the decision of what variables you will plot and fit beforerelying on them to do your work.

Data Points

All data points on a graph should be visible, but small enough to show their valuesunambiguously. If more that one data set are to be plotted on the same graph, thedata points from each set can be plotted using different shapes around the points,e.g. hollow squares, circles, triangles, etc as suggested below. As a rule, though, if


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two or more curves lie very close to each other, try to make their data points asdistinguishable as possible, i.e. small filled squares or triangles might look verysimilar, making one of them hollow would allow a future reader to identify whatpoints belong to which set more easily. (Note that if error bars are shown, the lastshape might be confusing.)

If uncertainties are known, you can add them graphically to the points as barsextending up and down (for uncertainty in the y value) and left and right (foruncertainty in the x value.) The length of the bars must be to scale. If theuncertainty is too small to plot, or not to be included, make sure you mention that inthe figure caption.

If more than one data set is present in the graph, dont forget to include a legend.

Fitting the data

It is often desired to perform some kind of fit to the experimental data that should follow

a known or expected function. Data that is plotted to only show a distribution are generally

not connected, but sometimes it is desired to connect the points to show a certain

relationship. When fitting a function to data points, the points are not connected, but the

fitted function is plotted on the graph with the points. Here, well discuss the procedure for

performing a linear fit, since, as mentioned above, it is the only data fitting that can be done

reliably without a computer.

There are two common and related purposed for fitting experimental data. One is to

verify a theoretically predicted functional dependence (such as determining the value of an

attenuation coefficient of an absorber for photon shielding), and another is to determine theaverage value and experimental uncertainty of the parameters, e.g. the slope, m, and the

intercept, b, for a linear fit y=mx+b.

To find the best linear fit for the experimental data points, it is necessary to draw astraight line which passes through all of the uncertainty intervals of all points in thegraph, or at least as close as possible to all of the points. Make sure there isapproximately the same number of data points on both sides of the fitted line.

To find the slope of the fitted line, pick two points at or near the ends of the line (notjust the two closest data points), and calculate the average values of the slope andintercept, maveand bave.

There are a couple of different ways to calculate the uncertainties of the estimatedslope and intercept. A computer may be able to do this job for you using a leastsquares fit, and it would provide the fitting parameters with a calculated uncertainty.But when the fitting is done by hand, the experimenter will have to find two lines withmaximum and minimum slopes mmaxand mmin that still fit the experimental datapoints reasonably well. Then the uncertainty of the slope, m is defined as


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max min

2

m m

m

=

An example of such a fitting is shown in Figs. 1a and 1b. Note that the uncertainty

estimated by hand is normally larger that what would be calculated by performing a

weighted least squares fit due to the crudeness of the method.A graph should always be accompanied by a caption, which provides a brief description

of the content, and together with the legend provide specific information about the

displayed data set(s), and the fitting function.


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Figure 1a: Hand plot of decay of116In counts measured with a G-M detector in lab. Thesolid line is a best-fit of the data points, and the dotted lines represent an approximate fit tothe error.


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Figure 1b: Excel plot of the same data, with y-error only (no error assumed in time

measurement)

1

1Note that error bars could be included for the x dimension, if you assume that you were able to start your

counts within one second of the appropriate time. The x-error would then be 1s.

Calculated Best Fit Line:y=(-0.010490.0002)x+(9.6240.004)

Measured Decay of In-116

9.150

9.200

9.250

9.300

9.350

9.400

9.450

9.500

9.550

9.600

9.650

0 10 20 30 40 50

Start Time of Count Relative to Removal from Neut. Flux

(minutes)

ln(CR/60s)

ln(CR) Linear (ln(CR))


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APPENDIX C: STEPS TO FINDING A TRACE AND SIGNAL OF INTEREST ON ANOSCILLOSCOPE (Tektronix-Analog)

1. Turn power ON to oscilloscope.

2. Set vertical input switch (AC-GND-DC) to GND.

3. Set vertical scale (VOLTS/CM) to maximum (usually about 5 volts/cm).

4. Set the horizontal scale (TIME/CM) to about 1 millisec/cm.

5. Set both the vertical and horizontal position controls to their mid-range.

6. Set TRIGGER to AUTO.

7. Increase INTENSITY to maximum.

NOTE: Reduce INTENSITY as soon as possible. The phosphorus is more easily burnedthan most people realize.

NOTE: At this point there should be a trace (line) on the screen.

8. Adjust FOCUS and INTENSITY as needed but keep the INTENSITY temporarily higher thanusual because some pulses can be dim.

9. Rotate the vertical POSITION control of the channel you are using to move the line to thecenter of screen.

10. Move the horizontal POSITION control until the beginning of the trace is one centimeter fromthe left side of the graticule.

NOTE: This is the normal location of the horizontal POSITION control. When it is moved formeasurement reasons it should be returned to this setting.

11. Move the input switch from GND to DC.

You should now be able to see some pulses --- the amplitude may be small, if so, increase

the gain (VOLTS/CM) one step at a time until you see either a + or - pulse of the desiredamplitude (1 or 2 cm). The pulses may be very narrow and probably will be moving acrossthe screen.

12. Adjust the time scale (TIME/CM) so the width of the pulses are 2 to 3cm.

13. Decide upon the source you wish to use as a trigger and set to INTERNAL, CHANNEL 1 or 2;LINE; orEXTERNAL (usually INTERNAL, CHANNEL 1).

14. Decided whether the pulse is positive or negative and set the trigger direction (+ or -) switch tothe proper position.

15. Turn the TRIGGER from AUTO to NORMAL.

The trace may disappear but adjust the trigger level until the pulse is again observed on the

screen.

16. Alternately adjust the LEVEL, TIME/DIVISION, VOLTS/DIVISION, and vertical POSITIONcontrols until the first pulse is viewable and as large as possible.

17. If you change the input signals, go back to step 1.


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NE L b t P d 20 11 J 2011

APPENDIX D: Finding a Trace and the Signal of Interest on a Digital Oscilloscope

1. Turn the power on to oscilloscope.

2. Wait until the display shows that all power-on tests have been passed. Be aware that thescope has about a 20-minute warmup period.

3. Push the [VERTICAL] CH 1 MENU button. Repeat until 1 appears on the left side of thescreen.

4. Press the soft keys (also known as: screen buttons, side-menu buttons, or bezel buttons) toobtain the following settings:

a. Coupling: DC, BW Limit: OFF, Volts/Div: Coarse, Probe: 1X,

b. Invert: Off

5. Observe the lower left corner of the screen. Adjust the [VERTICAL] VOLTS/DIV coarse gainknob until CH1 5.00V (i.e. 5 volts per division) appears in the lower left corner.

6. Press the [TRIGGER] TRIG MENU button to bring up the triggering options. Use the softkeys to select:

a. Type: Edge, Source: CH1 (or CH2 depending on the input you want use.),

b. Slope: Rising (or Falling, depending on the signal.), Mode: Auto,

c. Coupling: HF Reject (or Noise Reject, AC, or DC as required)

7. Press the [HORIZONTAL] HORIZ MENU to bring up the options. Using the soft keysset:

a. Main: (i.e. press the top soft key), Trig Knob: Level

8. Observe the bottom center of the screen. Adjust the [HORIZONTAL] (SEC/DIV) until 1ms (1millisec/div) appears.

9. Set both the [VERTICAL] and [HORIZONTAL] positioning arrows (POSITION) to 0,0.

10. Adjust the [VERTICAL] (POSITION) and [VERTICAL] (VOLTS/DIV), [HORIZONTAL](POSITION) and [HORIZONTAL] (SEC/DIV), and/or [TRIGGER] (LEVEL) / TRIG MENU,until a stable viewable and desired signal (wave shape) is observed.

11. If there is no trace, check that the [TRIGGER] (LEVEL) is not set at too high or low (i.e.above or below the actual signal level). Observe the arrows on the right screen edge theseare indicating the location of the signal.

12. Once a trace is displayed, adjust the gain, VOLTS/DIV, SEC/DIV, and vertical POSITIONcontrols until the first pulse is viewable and as large as possible (i.e. use as much of thescreen as possible).. Note: Most signals consist of 2 or 3 repeats or one wave shape, 2 to 3divisions wide and always greater than 1 division tall.

13. If the input signal is changed, go back to step 3.

205 sp11 lab prac-proc

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