Irina Lyublinskaya, Gregg Wolfe, Douglas Ingram , Liza Pujji
ISBN #9781938168932
2,282 Questions
Homework Questions
This section provides a comprehensive overview of how nuclear physics underpins many medical and industrial applications. Medical imaging techniques such as SPECT and PET rely on radiopharmaceuticals and sophisticated detection systems like the Anger camera, while the biological effects of ionizing radiation are quantified using units such as rad, Gy, rem, and Sv, taking RBE into account. In therapeutics, radiotherapy is employed to treat cancer by maximizing the dose to malignant cells while minimizing damage to healthy tissue. Additionally, the text examines the use of ionizing radiation in food irradiation, and compares the energy production processes in nuclear fusion and fission, highlighting the principles of chain reactions, critical mass, and the design of nuclear weapons. Understanding these fundamental concepts is essential for appreciating both beneficial applications and potential risks associated with nuclear physics.
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A neutron generator uses an $\alpha$ source, such as radium, to bombard beryllium, inducing the reaction $^{4} \mathrm{He}+^{9} \mathrm{Be} \rightarrow^{12} \mathrm{C}+n .$ Such neutron sources are called RaBe sources, or PuBe sources if they use plutonium to get the $\alpha$ s. Calculate the energy output of the reaction in MeV.
Neutrons from a source (perhaps the one discussed in the preceding problem) bombard natural molybdenum, which is 24 percent $^{98}$ Mo. What is the energy output of the reaction $98 \mathrm{Mo}+n \rightarrow^{99} \mathrm{Mo}+\gamma ?$ The mass of 98 $\mathrm{Mo}$ is given in
The purpose of producing 99 Mo (usually by neutron activation of natural molybdenum, as in the preceding problem) is to produce $99 \mathrm{~m} \mathrm{Tc}$. Using the rules, verify that the $\beta^{-}$ decay of $99 \mathrm{Mo}$ produces $99 \mathrm{~m} \mathrm{Tc} .$ (Most $99 \mathrm{~m} \mathrm{Tc}$ nuclei produced in this decay are left in a metastable excited state denoted ${ }^{99 \mathrm{~m}} \mathrm{Tc} .$.)
(a) Two annihilation $\gamma$ rays in a PET scan originate at the same point and travel to detectors on either side of the patient. If the point of origin is 9.00 $\mathrm{cm}$ closer to one of the detectors, what is the difference in arrival times of the photons? (This could be used to give position information, but the time difference is small enough to make it difficult.) (b) How accurately would you need to be able to measure arrival time differences to get a position resolution of 1.00 $\mathrm{mm} ?$
Table 32.1 indicates that 7.50 $\mathrm{mCi}$ of 99 $\mathrm{m}$ Tc is used in a brain scan. What is the mass of technetium?