MPHY214 Hofstra University Radiological Physics & Radiation Midterm Exam

Anonymous

Question Description

I attached my midterm's Qs to be solve in 6 to 9 hours. They are 6 Qs in the Nuclear medicine.

Unformatted Attachment Preview

Hofstra 2019 Fall MPHY 214 Midterm Exam Rules of the exam A. There are six questions in this exam. B. The full marks of this exam are 100 points. It is worth 20% of your final grade. C. The exam begins on 8:00 am, 11/3/2019 and ends on 12:00 noon, 11/6/2018. D. You are NOT allowed to discuss your work with other people. E. Please type your answers in a MS Word document and email me the final document by the deadline. F. You need to show all steps to earn full credit. Just putting the answer on the paper is not enough. G. If you donโ€™t want to type, please write your anwers neatly. You might lose points if I can not read your writings. 1. Two x-rays detectors were used to measure the intensity of an x-ray souce at the same location. Each dectior was used to measure the intensity 100 times and the averaged intensity was the same (1000) for both detectors. However, the standard deviation was 50 for the first dector and 35 for the second detector. Can you explanation what might cause such discrepancy? (10 points) 2. A ๏ง-ray h๏ฎ1, is emitted by a radioactive atom in V. The photon undergoes triplet production, giving kinetic energy T1 and T2 to the electrons and T3 to the positron. Illustrate the events in the following questions using a circle diagram similar to that ๐‘›๐‘’๐‘ก used in the text book, and calculate ๐œ–๐‘ก๐‘Ÿ , ๐œ€๐‘ก๐‘Ÿ , ๐œ€, K, Kc, and D. (10 points) a. Both electrons leave V with kinetic energy Tโ€™1 and Tโ€™2. The positron runs its course in V and still has kinetic energy Tโ€™3 when it is annihilated inside V. The resulting two photons escaped from V b. Electron 1 stops within the volume and electron2 leaves V with kinetic energy Tโ€™2. The positron also leaves V with kinetic energy Tโ€™3 and still has kinetic energy Tโ€™โ€™3 when it is annihilated outside V. 3. In radioactive decay from an initially pure parent, the parentโ€™s and daughterโ€™s half-lives are respectively ๐œ1โ„2,๐‘ƒ and ๐œ1โ„2,๐ท . Let ๐‘ก๐‘,๐‘’๐‘ž be the time when the daughterโ€™s population is equel to the parentโ€™s population: (20 points) a. What is the general form for ๐‘ก๐‘,๐‘’๐‘ž ? What are the assumptions for your answers? b. What is ๐‘ก๐‘,๐‘’๐‘ž if ๐œ1โ„2,๐‘ƒ = ๐œ1โ„2,๐ท ? c. Plot the populations of parent and daughter as a function of time for ๐œ1โ„2,๐‘ƒ and ๐œ1โ„2,๐ท of you choice when the assumptions in (a) hold true. d. Plot the populations of parent and daughter as a function of time for ๐œ1โ„2,๐‘ƒ and ๐œ1โ„2,๐ท of you choice when the assumptions in (a) are violated. 4. What is the average dose (Gy) in an tin foil of thickness 1.2 g/cm2, from being irradiated perpendicularly by 1012 e/cm2 of energy T0 = 10 MeV. (20 points) 5. Appendix A is the TMR table of the 15X beam of a linear accelerator measures with ๐‘†๐ท๐ท = 100 cm from the source. Solve the following questions for the 10ร—10 cm2 field size using the Greeningโ€™s approximation. Note: there are some typos on the slide for โ€œRelation between TPR or PDDโ€ for โ€œAndreo CHAPTER 7. X-ray Production and Quality.โ€ Please check the textbook for the correct formulas. (20 points) ๐‘†๐ท๐ท ๐‘†๐‘†๐ท ๐‘†๐‘†๐ท a. What are ๐œ‡๐‘’๐‘“๐‘“,๐‘ , ๐œ‡๐‘’๐‘“๐‘“,๐‘ , ๐œ‡๐‘’๐‘“๐‘“,๐‘’ and ๐‘งmax ? b. Plot the PDD curve and compare it with the measured PDD in Appendix B. 6. Design an experiment for measuring ๐œ‡๐‘ก๐‘Ÿ . (20 points) ...
Purchase answer to see full attachment

Tutor Answer

brianreyes958
School: UC Berkeley

Attached.

Hofstra 2019 Fall MPHY 214

Midterm Exam

1. Two x-rays detectors were used to measure the intensity of an x-ray source at the same
location. Each detector was used to measure the intensity 100 times and the averaged
intensity was the same (1000) for both detectors. However, the standard deviation was 50
for the first detector and 35 for the second detector. Can you explanation what might
cause such discrepancy? (10 points)
The x-ray source is assumed to have a strictly random occurrence in terms of the time
interval taken for x-ray to impinge on the detector and an a given point per unit area. The
distribution of the detection is assumed to be Poisson. The mean represents the average
intensity detected which is a is affected by the energy of the source and its distance to the
detector. For same source and distance, the average intensity would same. However, the
standard deviation is a square root of the ratio expected value of the number of rays
detected to the number of measurements. Since the detector counts every incident ray, the
standard deviation is entirely stochastic in nature.

2. A

-ray hv1, is emitted by a radioactive atom in V. The photon undergoes triplet

production, giving kinetic energy T1 and T2 to the electrons and T3 to the positron.
๐‘ก๐‘Ÿ

Illustrate the events in the following questions using a circle diagram similar to that
used in the text book, and calculate ๐œ–๐‘ก๐‘Ÿ, ๐œ€๐‘›๐‘’๐‘ก, ๐œ€, K, Kc, and D. (10 points)
a. Both electrons leave V with kinetic energy Tโ€™1 and Tโ€™2. The positron runs its
course in V and still has kinetic energy Tโ€™3 when it is annihi...

flag Report DMCA
Review

Anonymous
Top quality work from this tutor! Iโ€™ll be back!

Anonymous
Heard about Studypool for a while and finally tried it. Glad I did caus this was really helpful.

Anonymous
Thank you! Reasonably priced given the quality

Studypool
4.7
Trustpilot
4.5
Sitejabber
4.4

Brown University





1271 Tutors

California Institute of Technology




2131 Tutors

Carnegie Mellon University




982 Tutors

Columbia University





1256 Tutors

Dartmouth University





2113 Tutors

Emory University





2279 Tutors

Harvard University





599 Tutors

Massachusetts Institute of Technology



2319 Tutors

New York University





1645 Tutors

Notre Dam University





1911 Tutors

Oklahoma University





2122 Tutors

Pennsylvania State University





932 Tutors

Princeton University





1211 Tutors

Stanford University





983 Tutors

University of California





1282 Tutors

Oxford University





123 Tutors

Yale University





2325 Tutors