Lab 1: Absorption of Nuclear Radiation
PHY 114: General Physics Laboratory
Lab 1: Absorption of Nuclear Radiation
09/04/13
Abstract
Nuclear physics was practiced to find the value of tau. After 8 trials of using a G-M counter and 8 different mass thicknesses of polyethylene, a graph was formed and tau was calculated to be 0.1931 cm^2/g, an error of 3.57% from the accepted value of 0.2 cm^2/g.
Experiment was also used as an intro to using basic lab equipment, computer programs and calculating errors. With many different calculation, the latter was easily fulfilled and more practice with the equipment and programs will lead to a more experienced familiarity to the physics lab.
Objectives
Group 7 was instructed to observe the absorption of beta particles when passing through different thicknesses of polyethylene absorbers. This also helped group 7 practice how to use basic instrumentation of nuclear physics.
Procedure
It was necessary to determine the operating voltage for the G-M counter. Group 7 put the beta source right underneath the sensor and started with a voltage of 200 V, then slowly added more and more voltage until the rate of electrons counted was constant. (This number was 257 V. To this number, 75 more volts were added for a voltage of 232 V. This was left as a constant for the remainder of the experiment.
The background radiation was calculated next. This was done by removing the beta radiation and letting the sensor run for ten minutes to pick up what radiation different sources in the room would let off. The number was was 12.2 counts. This was divided by ten for an average of 12.2 counts/minute.
The beta source was replaced , but on the second shelf of the counter. Eight different trials were conducted, introducing eight different thicknesses of polyethylene absorbers ranging from 0-0.610 g/cm^2, with the 0 g/cm^2 trial not having anything anything in between the beta source and the sensor. Results were recorded.
Experimental data
Table 1: 8
Lab 1: Absorption of Nuclear Radiation
09/04/13
Abstract
Nuclear physics was practiced to find the value of tau. After 8 trials of using a G-M counter and 8 different mass thicknesses of polyethylene, a graph was formed and tau was calculated to be 0.1931 cm^2/g, an error of 3.57% from the accepted value of 0.2 cm^2/g.
Experiment was also used as an intro to using basic lab equipment, computer programs and calculating errors. With many different calculation, the latter was easily fulfilled and more practice with the equipment and programs will lead to a more experienced familiarity to the physics lab.
Objectives
Group 7 was instructed to observe the absorption of beta particles when passing through different thicknesses of polyethylene absorbers. This also helped group 7 practice how to use basic instrumentation of nuclear physics.
Procedure
It was necessary to determine the operating voltage for the G-M counter. Group 7 put the beta source right underneath the sensor and started with a voltage of 200 V, then slowly added more and more voltage until the rate of electrons counted was constant. (This number was 257 V. To this number, 75 more volts were added for a voltage of 232 V. This was left as a constant for the remainder of the experiment.
The background radiation was calculated next. This was done by removing the beta radiation and letting the sensor run for ten minutes to pick up what radiation different sources in the room would let off. The number was was 12.2 counts. This was divided by ten for an average of 12.2 counts/minute.
The beta source was replaced , but on the second shelf of the counter. Eight different trials were conducted, introducing eight different thicknesses of polyethylene absorbers ranging from 0-0.610 g/cm^2, with the 0 g/cm^2 trial not having anything anything in between the beta source and the sensor. Results were recorded.
Experimental data
Table 1: 8