RADIATIN Read Me

VERNIER SOFTWARE
RADIATION MEASUREMENT WITH
THE TI CBL™ AND TI-73, TI-82, TI-83, TI-83 Plus TI-85, TI-86, TI-89, TI-92, and TI-92 Plus

I. OVERVIEW
II. SENDING THE PROGRAM FILE
III. PROTECTED FILE
IV. GENERAL DESCRIPTION OF THE RADIATIN PROGRAM
V. SPECIAL NOTE ON COLLECTING DATA WITH CBL
VI. PROGRAM DESIGN NOTES

I. OVERVIEW

This document describes the use of a program that helps you perform experiments with a TI Graphing Calculator, the TI Calculator-Based Laboratory™ (CBL) System and a radiation monitor. The RADIATIN program supports all Vernier radiation monitors. Data collection modes can be used to 1) collect background radiation, 2) collect and monitor histogram data, 3) collect data to determine the half-life of an isotope, and 4) collect data as a function of distance or shielding.

II. SENDING THE PROGRAM FILE

You will need to use TI-GRAPH LINK™ to send the RADIATIN.??p file to your calculator. The actual steps will depend upon the calculator and computer you are using. If you are unsure of this process, refer to the Graph Link manual for the calculator and computer you will be using. Not all calculators are handled the same.

III. PROTECTED PROGRAM FILE

The calculator program described, except for the TI-85, has been protected so that it cannot be edited on the calculator. This feature prevents students from accidentally corrupting the program. The easiest way to edit protected files is with the TI-GRAPH LINK program. The TI-GRAPH LINK manuals describe the protecting and unprotecting process.

IV. GENERAL DESCRIPTION OF THE RADIATIN PROGRAM

The RADIATIN program provides a wide range of options as you create and run experiments. To begin, run the RADIATIN.??p program. The RADIATIN program uses a series of menus allowing you to set up different types of experiments.

Connect the radiation monitor to Channel 1 of the CBL, as the readout directs. The calculator will then attempt to communicate with the CBL. If the CBL is not powered up or the CBL and calculator are not properly linked, an error message will appear. Check to see that the link cord is firmly connected to each device and that the CBL is powered up - press the [ON/HALT] button on the CBL. Correct any problems before continuing.

The following general description applies to the use of this program on your calculator. For specific help in executing programs on the calculator, refer to the manual. To begin, run the RADIATIN program. After an introductory screen, the following MAIN MENU will appear:

***MAIN MENU***
1:COLLECT DATA
2:VIEW GRAPH
3:VIEW DATA
4:SET NO. SAMPLE
5:QUIT

*****************************************************************

From the MAIN MENU you can set up an experiment by choosing the first option, COLLECT DATA. The following menu provides you with a choice of data-collection modes:

DATA COLLECTION
1:BACKGROUND
2:MONITOR/HISTOG
3:HALF-LIFE
4:TRIGGER/PROMPT
5:RETURN

RADIATIN allows you to collect the data from the radiation monitor in different ways. The BACKGROUND mode does not plot a graph after the data is collected because it determines the background rate in counts/minute. After the background radiation is collected, the calculator will ask if you wish to adjust the rate for later readings.

ADJUST RATE
1: YES
2: NO

For more accurate subsequent measurements, the background reading will be subtracted from each of your data readings if you select YES.

The MONITOR/HISTOG mode option allows you to monitor data from a radioactive source, and then displays the results as a histogram.

The HALF-LIFE mode option is used to collect rate vs. time data. It is particularly useful if you are collecting data from an isotope with a relatively small half-life. When the data collection in this mode is complete, the axis-labels L1 and L2 are displayed. To view the graph, press ENTER. NOTE: After you do a half life, the calculator calculates the half and puts it into the variable H.

The TRIGGER/PROMPT option in the DATA COLLECTION menu is used to perform experiments in which the independent variable is entered using the calculator keyboard while the dependent variable is measured with the CBL probe or probes. For example, you could use a radiation monitor to measure the rate as the distance from the source changes. When the [TRIGGER] button on the CBL is pressed, the CBL measures the radiation and you will be prompted to enter the distance from the source.

You can also use the TRIGGER/PROMPT option when conducting shielding studies. For example, you could use the radiation monitor to measure the rate as silver foil shields are placed between the source and the radiation monitor. When the [TRIGGER] button on the CBL is pressed, the CBL measures the radiation and you will be prompted to enter the number of pieces of silver foil.

After you select this option, a screen will appear prompting you to press the CBL [TRIGGER] button when you are ready to take a sample. You will then be prompted to enter the independent variable. The following menu then appears:

TRIGGER PROMPT/PROMPT
1: MORE DATA
2: STOP AND GRAPH

If you select option 1:MORE DATA, the CBL will be set up to make another reading. If you select option 2:STOP AND GRAPH, data collection will stop and a graph will be displayed.

The fifth option, RETURN, will return you to the MAIN MENU.
***********************************************************************

The second option, VIEW GRAPH, on the MAIN MENU allows you to review previously set up graphs. Each time you view a graph, you will be able to read off the coordinates of each data point. The coordinates of the first point will be displayed at the bottom of the screen. To view other points use the left and right arrow buttons on the calculator to move across the screen. These graphs use the "ZoomStat" option to provide automatic scaling of axes. You may prefer to quit the program to set your own scaling.

The third option, VIEW DATA, on the MAIN MENU allows you to review and edit previously collected data. Follow the directions on the screen until the data lists are presented. The cursor keys on the calculator can be used to delete and edit data in the lists.

The fourth option, SET NO. SAMPLES, on the MAIN MENU allows you to select a different number of samples to be collected before a reading is stored. For example, if you enter 100, then the Radiation Monitor and CBL will take readings for as long as it takes to collect 100 readings; if you have a weak source, you may want to set this to a small number of samples. A stronger source will require more readings.

The fifth option, EXIT, on the MAIN MENU allows you to exit the RADIATIN program and leaves a blank screen.

DATA STORAGE

During data collection data is stored in the following lists:

time or independent variable in L1

radiation monitor counts/interval in L2

V. SPECIAL NOTE ON COLLECTING DATA WITH CBL

Before collecting data, it is important to know that this program does not collect radiation data in the traditional sense. For example, when using Vernier Event Counter or Logger Pro software on a computer, the program counts events over a specific time interval, then it determines the count rate. (Scalar counters work in the same manner.) In contrast, the CBL program has to count a specific number of events, determine the time, and calculate the rate. This approach can present problems with some radioactive sources. For example, since the default setting for the number of counts is 50, collecting data with weak sources may take a very long time. In that case, it may be necessary to reduce the number of counts collected in a sample. This is done in the SET NO. SAMPLES option on the MAIN MENU. You can also use this option to increase the number of samples when using a source with a high count rate.

VI. PROGRAM DESIGN NOTES

These programs have been written to support Texas Instruments and Vernier probes with the CBL. We hope they help you perform a variety of experiments with this exciting technology. Please feel free to share these programs with other teachers and students. Hopefully they have been written in such a way that you can modify them for your particular application.

The programs were designed and written by Rick Sorensen and Matthew Denton. Please contact Vernier Software if you have any questions concerning these programs or the use of our probes with the programs.

August 14, 1998