Disk Graph 2 1 15 Cm

Transcribed image text: Distance (em) Disc Background Count Net CPM 40 20 1 6 6 10 5 Gross CPM 32 56 118 2411 12 21 48 112 40 20 2. 0) 10 5 Counts 5 cm Disc 1: Counts 10 cm 2.09 or 2 times 1 20 simplifies to 118 112 48 simplifies to Counts 5 cm Disc 2: Counts 10 cm 2.33 1 or 2 times Questions: 1. Why is the background radiation subtracted out of the gross counts per minute? Because Geiger counte detects radiation from both the backround and the source, Which shielding material provided the best protection? 2. Lead had the best shielding material for protection 3. Is there a correlation between distance and exposure? Support your answer with data from your experiment Yes the closer the unit the amount of exposure increases Sheet sheet where you will enter your data for the Geiger Counter simulation There are four simulations you must run in order to complete the lab. Simulation 1 will be used to determine the background count. Each time you click read, it will read the background count in counts per minute (CPM). (Note: It is not in real time. The run is complete when the counter stops counting). Average out the three runs to determine the average background count. You will use this number throughout the rest of the lab. Simulation #2 will be used for parts 2 and 3. Again, each time you hit read, the trial lasts one minute (not in real time). Drag dise one on to the holder. Determine the gross CPM and record your data. Do this two more times. Subtract out the background count to get the net CPM. Now do this for disc 2. For part 3. you are going to determine the gross count over a longer period of time for disc I only. Keep in mind that each click on 'Read' is one minute. You will have to add up the counts to equal the number of minutes indicated by the table. Subtract out the background count (watch your units!) to get the net CPM. Do this for 1.3, and 5 minutes. Record your data. Calculate the data for 10 and 30 minutes using the data you collected for 1, 3, and 5 minutes. Simulation #3 is used for part 4. Read the gross count for one minute for disc I without any shielding. Then read the gross count for one minute using all of the shielding materials. Do the same for disc 2. Record your data. Simulation 14 is used for part 5. Determine the gross CPM for one minute for disc one and two at 5 cm. Move the probe for 10, 20 and 40 cm by clicking on the numbers to the left of the ruler. Read the gross CPM for discs ce one and two at each distance. Subtract out the background count to get the net CPM. Fill in the data to the formula below the table to calculate how many times more radiation you are exposed to at Sem than at 10cm for both discs. Data Tables Part Background Radiation Trial 1 Background Count (counts per minute) 8 8 3 19 3 2 3 The average background radiation is 6_counts per minute (cpm) the same number of protons but a different Substract backround count 6 Radiation Counts -6 Background Count Isotope Disc Disc 1 Gross CPM 214 238 240 102 118 6 Net CPM 208 232 234 96 Disc 2 112 85 from gross to net Subtract backround count Part 3: Time Background Count Time minutes) 1 3 5 Gross CPM 235 701 1147 Net CPM 229 683 6x3 6x 5 18 30 10 mobil 30 Muhibly 2.290 20,490 Discl subtract Part 4: Shielding S у с SC Dise Background Count Net CPM None Gross CPM 215 7 2 Glass 6. 209 1 -4 Disc 1 Aluminum Foil Lead Paper None 1 105 85 81 12 108 -5 99 19 75 Glass Disc 2 6. Aluminum Foil Lead 6 102 Paper deet Determine the type of radiation emitted from dise 1 and dise 2. Support your answers with data from 4 your experiment 4. Predict the approximate net CPM should be for 15 seconds of exposure to disc 2 in part 4. 5. Create a graph of net counts per minutes vs. distance for both discs. Draw a best fit line through the data points in an exponential fashion. You can draw this by hand NEATLY or use excel. Predict what the net CPM should be at 75cm and 25cm. b 5L C 0 st Background Count Net CPM 26 Die Distance (cm) 40 20 50 112 10 5 Gross CPM 32 5C 118 2411 12 21 48 112 40 20 15 2. 10 42 106 5 Counts 5 cm Disc 1: Counts 10 cm 1 241 2.09 simplifies to or a times 118 112 simplifies to 233 or 2_times 48 Disc 2: Counts 5 cm Counts 10 cm Questions: 1. Why is the background radiation subtracted out of the gross counts per minute? Because Geiger counte detects radiation from both the backround and the source, Which shielding material provided the best protection? Lead had the best dielding material for protection 2. 3. Is there a correlation between distance and exposure? Support your answer with data from your experiment increases Xes, the closer the unit the amount of exposure Chem 116 Online Lab 8: Virtual Geiger Counter Data Sheet Background: An isotope is an element that has the same number of protons but a different number of neutrons. Most elements on the periodic table have at least one stable isotope. But all elements on the periodic table have at least one unstable isotope. To achieve stability, unstable isotopes will shed matter and energy from their nucleus called radiation. Matter that emits radiation is said to be radioactive. Nuclear radiation has the ability to strip electrons from an atom or compound causing it to become an ion. These radioactive particles are called ionizing radiation There are three predominant types of nuclear radiation: Alpha, beta, and gamma. Alpha radiation is composed of two protons and two neutrons, which is the composition of the helium nucleus. While the heaviest radioactive particle, it is short lived. All an alpha particle has to do is steal two electrons from other substances and it becomes helium, Beta radiation is composed of an electron. While electrons do not reside in the nucleus, electrons are formed as a result of the decay of a neutron shown in the equation below. 'on lip+e The proton remains in the nucleus, which changes the element, but the electron is shot out of the nucleus as a tremendous rate, A beta particle needs to be slowed by matter in order to be incorporated into matter. This gives beta radiation greater energy than an alpha particle Gamma radiation is composed of light. Gamma radiation has a much shorter wavelength than X-rays, which gives it more energy than X-rays. In fact, gamma rays have the ability to pass through most matter. Radiation is detected using a Geiger counter. When a particle of radiation slams into the probe, the counter will record it. The Geiger counter can be set to display absolute count, in which the particle count will increase when a particle strikes the probe or it can be set to display count rate, which will average how many particles strike the probe over a particular period of time, usually in minutes. Without a radioactive source nearby, the Geiger counter will detect small amounts of radiation. This naturally occurring radiation is called background radiation. When you are measuring radiation from a concentrated source, the Geiger counter will detect radiation from both the background and the source. There are three ways to protect yourself from radiation emitted from concentrated sources. You may opt to shield yourself from radiation. What is used to block radiation depends on the type of radiation. Since alpha radiation has low energy, low density substances like your clothes provide adequate protection. Medium energy beta particles require something denser, like glass or aluminum. Blocking high energy gamma rays require substances with great density like lead or concrete. A second way to protect yourself from radiation is to keep your distance from the source. Lastly, spend less time near the source. The decay rate for radioactive isotopes is constant, therefore you can determine how much radiation should be emitted for a longer period of time by setting up a proportion for a shorter period of time. This is the data sheet where you will enter your data for the Geiger Counter simulation. Directions: There are four simulations you must run in order to complete the lab. Simulation #I will be used to determine the background count. Each time you click read, it will read the background count, in counts per minute (CPM). (Note: It is not in real time. The run is complete when the counter stops counting). Average out the three runs to determine the average background count. You will use this number throughout the rest of the lab. Simulation #2 will be used for parts 2 and 3. Again, each time you hit read, the trial lasts one minute (not in real time). Drag disc one on to the holder. Determine the gross CPM and record your data. Do this two more times. Subtract out the background count to get the net CPM. Now do this for disc 2. For part 3, you are going to determine the gross count over a longer period of time for disc I only. Keep in mind that each click on 'Read' is one minute. You will have to add up the counts to equal the number of minutes indicated by the table. Subtract out the background count (watch your units!) to get the net CPM. Do this for 1, 3, and 5 minutes, Record your data. Calculate the data for 10 and 30 minutes using the data you collected for 1, 3, and 5 minutes. Simulation #3 is used for part 4. Read the gross count for one minute for disc I without any shielding. Then read the gross count for one minute using all of the shielding materials. Do the same for disc 2. Record your data. Simulation #4 is used for part 5. Determine the gross CPM for one minute for disc one and two at 5 cm. Move the probe for 10, 20 and 40 cm by clicking on the numbers to the left of the ruler. Read the gross CPM for discs one and two at each distance. Subtract out the background count to get the net CPM. Fill in the data to the formula below the table to calculate how many times more radiation you are exposed to at Sem than at 10cm for both dises. Data Tables Part 1: Background Radiation Trial 1 Background Count (counts per minute) 8 8 3 19 3 2 3 The average background radiation is counts per minute (cpm) subtract backround count 6 sotope Radiation Counts Isotope Disc Background Count Disc 1 Gross CPM 214 238 240 102 118 9 Net CPM 20B 232 234 Disc 2 Part 3: Time Time (minutes) 1 Gross CPM 235 101 112 85 from gross to net Subtract backround count Background Count Net CPM 229 6x3 18 683 6x5 30 1.1.1 2.290 20,490 3 5 10 mobily 30 multibly Discl subtract Part 4: Shielding Disc Background Count None Net CPM 209 1 -4 Glass 6 Disc 1 Aluminum Foil Lead Paper Gross CPM 215 7 2 0 1. 105 85 81 12 108 None Glass -5 99 119 75 6 102 6 Disc 2 Aluminum Foil Lead Paper CS Disc Gross CPM Distance (cm) 40 Background Count Net CPM 26 50 20 6. 10 5 32 56 118 2411 12 21 48 112 241 40 20 2. 6 10 15 42 106 5 Disc 1: Counts 5 cm Counts 10 cm 240 2.09 simplifies to or 2 times 1 Counts 5 cm Disc 2: Counts 10 cm 118 112 48 simplifies to 2.33 or 2 times 1 Questions: 1. Why is the background radiation subtracted out of the gross counts per minute? Because Geiger counte detects radiation from both the backround and the source, Which shielding material provided the best protection? Lead had the best shielding material for protection 2. 3. Is there a correlation between distance and exposure? Support your answer with data from your experiment Yes, the closer the unit the amount of exposure increases Determine the type of radiation emitted from disc 1 and disc 2. Support your answers with data from your experiment 4. Predict the approximate net CPM should be for 15 seconds of exposure to dise 2 in part 4. 5. Create a graph of net counts per minutes vs. distance for both discs. Draw a best fit line through the data points in an exponential fashion. You can draw this by hand NEATLY or use excel. Predict what the net CPM should be at 75cm and 25cm.