1. Calculation Explanation 

In order to account for the total amount of radiation being emitted from the sample, an estimate of the surface area of radiation emittance had to be calculated. Due to the fact that only one Geiger-Müller tube was being used, the surface area of our detector could only detect a small set of a whole sphere that surrounds our sample. It was found that each sample was from our detector, which gives the radius of sphere of emittance.

Surface area of a sphere

in our case 

and thus 

Now we need to find out how many of our detectors will fit into this area. Measuring the radius of our circular detector we get

so

so the factor we will multiply our counts by is . We will call this constant  for simplicity.

Here are some more variables and constants we wish to define.

The total counts per minute measured in the blank room

The total counts  per minute measured for a sample

Amount of detectors in our sphere 

Average time it takes to digest a food product

Max energy of a beta particle  J

From these constants and variables, we can see that the total amount of energy absorbed due to radiation  

To calculate the total amount one must consume of an object to induce death, it was found that 2 of radiation was enough to give ones self acute radiation poisoning over a period of 6-8 weeks. 1 . So assuming an average person who weighs The amount of energy to kill them would be

lastly to find the total amount one must eat of a given food would be our equation above over

(1)  

2. Data 

For collecting our data, the sample was placed into a 20 gallon plastic container with the Geiger counter pointing downwards at the sample, and the Vernier LabQuest was placed away from the container to minimize any additional environmental variables. The samples were placed 6 inches away from each sample. The container was covered before testing began, and all testing was conducted in a dry room at 75°F. The following samples were taken: a blank, a banana, a tablespoon of peanut butter, and (1) cup of beer. Each sample was obtained from the same grocery store, and a single serving size (the entire sample) was taken from each of the sources. Below in Figure 1 is the data that was collected. The ellipses abbreviate the data that was collected for the sake of brevity.

Figure 1 – Raw Data Collection for Blank, Banana, Peanut Butter, and Beer 

3. Results

The data was collected for a period of 10 minutes at intervals of 10 seconds through the Vernier LabQuest and was compiled into a data chart on the devices. The samples that were tested, as mentioned above, were as follows: a blank, a banana, peanut butter, Beck’s beer. The data was then transferred to Microsoft Excel where calculations as shown in two sections above were conducted. A total summation of all the radioactive counts are shown in Figure 1, and a line graph of the variation of counts per 10 second interval are shown in Figure 2.

 

Figure 2 – Summation of Counts for Blank, Banana, Peanut Butter, and Beer  

Figure 3 – Counts vs Time for Blank, Banana, Peanut Butter, and Beer  

For each of the samples, the standard deviation for the blank, banana, peanut butter, and beer are as follows, respectively: 1.46, 1.33, 1.42, 1.72. These standard deviations indicate a fair spread given the maximum and minimum values that were recorded for each sample. Beer was found to have the most radiation whereas peanut butter did not emit any; the banana was found to emit radiation but less than that of beer.

When calculating how much one must consume to induce death, it was found that it takes on average about four hours to digest the radioactive isotopes. The four hours was converted to minutes to keep units consistent in calculations. In addition, the units for counts per minutes were accounted for by dividing by ten in the calculation. Figure 4 below shows how much of one of the samples you would have to consume to to induce radiation poisoning to the point of death. The Merck Manual of Radiation Exposure and Contamination was used to data in regards to how many Gy’s it would take to kill a person in a matter of 6-8 weeks.

Figure 4 – Amount of a Serving Size of a Banana, Peanut Butter, or Beer to consume to Induce Death at 2 Gy  

4. Conclusion

It was found that you would have to consume more beer than bananas to induce radiation poisoning to the point of death over a period of 6-8 weeks. In short, it is practically improbable for one to die from consuming these objects in excess because of the little radiation that is emitted from these sources. This makes sense because the FDA (an in other countries) would not allow for these products to be sold if they posed a radiation risk to consumers. In the data that was collected, it was shown that the peanut butter emitted less radiation than the blank itself. This can be explained by the setup of the experiment. Because we are only using one Geiger counter, we are only able to approximate the radiation emitted in all directions and in the different amounts. Thus, it was possible for some samples to have higher or lower readings than others.

Through the course of this experiment, a better understanding of constructing controlled experiments, use of a Geiger-Müller tube, and energy calculations/conversions amongst units was obtained. In addition, learning more about the methods of collections through different units such as Sieverts or Greys and Counts vs Dosage were better understood through research and trials within this experiment.

If this experiment could have been setup differently, the first change that would have been implemented would have been the use of multiple Geiger-Müller tubes. If more tubes were used, more accurate data could have been collected and our theoretical approximations of sample emittance could have been more accurate. In addition, a simulation of digestion using HCl at a pH similar to that of stomach acid would have been conducted to see what happens to the radioactive isotope once consumed as the assumption in this project was that radiation ceased upon digestion. If the experiment were conducted for a longer period of time, more samples would have been taken over a longer period of time to look for patterns or see if the rate of emittance follows the approximate rate of decay for the radioactive isotopes in each sample. In addition, the use of highly radioactive samples would have been used to add variance to the control group versus a blank. This experiment can be repeated using one Geiger-Müller tube, a Vernier LabQuest machine, a plastic container, and the samples used in this experiment.

For collecting our data, the sample was placed into a 20 gallon plastic container with the Geiger counter pointing downwards at the sample, and the Vernier LabQuest was placed away from the container to minimize any additional environmental variables. The samples were placed 6 inches away from each sample. The container was covered before testing began, and all testing was conducted in a dry room at 75°F. Pictures are shown below.

The data was collected for a period of 10 minutes at intervals of 10 second through the Vernier LabQuest and was compiled into a data chart on the devices. The samples that were tested were as follows: a banana, peanut butter, Beck’s beer, and a blank. The data was then transferred to Microsoft Excel where various calculation were conducted. A total summation of all the radioactive counts are shown in Figure 1, and a line graph of the variation of counts per 10 second interval are shown in Figure 2. 

 

Figure 1 – Summation of Counts

Figure 2 – Counts over Time

The data overall showed that radiation was indeed being emitted from each of the samples, however, the type of radiation has yet to be determined.

Roles: Each member will be collaborating on conducting initial research on radioactivity, how it pertains to food, performing the experiments, and doing the calculations. In terms of initial research, each member will submit at least one scholarly article pertaining to food radiation in addition to an article about radiation in general. However, the rest of the project will be completed together.

Equipment Used: Vernier Radiation Monitor (to measure the emitted radiation at a given point), Laptop for Research, LabQuest Monitoring Software, various foods (based on list created), and a knife for cutting open food

Science/Technology Involved: The Vernier Radiation Monitor contains a Geiger-Müeller tube, which is built-in in a durable case for portability as well as flexibility when testing. A geiger counter is a type of particle detector, which measures ionizing radiation in a low-pressure gas in the tube. Geiger-Müller tubes have two main elements, which are the tube itself, and the electronics. The Geiger-Müller contains a gas, such as halogens, that are under low pressure. An electrical charge is sent through when a particle or photon of radiation ionizes the gas particles. In order to read a measurable number, the electronics in the tube are able to amplify each ionization via Townsend avalanche effect. Luckily, it requires no battery as it receives power from the data-collection interface. There is a thin glass panel which is then encased by a metal screen, which allows alpha radiation to be measured, along with beta and gamma radiation. This device will allow us to use radiation statistics built into the LabQuest machine, measure the rates of nuclear decay for various food object, and monitor radon progeny. Radon progeny is short-lived radioactive decay of radon-222 that can no longer change into longer life lead isotopes upon decaying.

Activity Plan: 

1. Decide on various foods to be tested for radiation
2. Make control measurements of general radiation in the surrounding environment
3. Construct a container that will keep out as much background radiation as possible
4. Conduct experiment, measuring each food and being sure to account for environmental radiation and associated variables (where food comes from geographically as well as store location, freshness, and/or variety of fruit); conduct several trials for each food
5. Calculate the amount of times a given food would have to be consumed to develop acute radiation syndrome
6. Analyze data via Excel for standard statistics

Expected Outcome: We expect to measure a minute about of radiation that is emitted from foods that we test. However, due to FDA regulations, it is most likely that food at your typical supermarket does not contain an outstanding amount of radiation. However, large consumption of various products can lead to acute radiation poisoning, and will be interesting to compare to FDA regulations as well as other studies in the field.

References: 

Morris, S. H. (1948). US Patent No. 2,522,902. Washington, DC: U.S. Patent and Trademark Office.

George, A. C. (1996). State-of-the-art instruments for measuring radon/thoron and their progeny in dwellings-a review. Health physics, 70(4), 451-463.