Introduction To Health Physics
5th Edition
ISBN: 9780071835275
Author: Johnson, Thomas E. (thomas Edward), Cember, Herman.
Publisher: Mcgraw-hill Education,
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 9, Problem 9.21P
To determine
The gamma threshold energy.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
The linear attenuation coefficient for 2.0-MeV gamma rays in water is 4.9 m-1 and 52 m-1 in lead. What thickness of water would give the same shielding for gamma rays as 15 mm of lead?
a. A dental x-ray machine has a 60 kV accelerating voltage and a tungsten target. Atypical exposure uses an 8.0 mA electron current for 18 s. What is the approximatepower of the x-ray emission? The conversion efficiency is not known precisely, so aone-significant-figure answer is appropriate.
b. What is the x-ray intensity at the jaw, 15 cm from the source? Assume that the x raysare emitted uniformly in all directions from a single point.
c. A molar tooth can be approximated as a 9-mm-diameter, 20-mm-long cylinder. X raysimpinge on a molar from the side, perpendicular to the axis of the cylinder. Approxi-mately what x-ray energy enters a molar during the exposure?
The count rate for a particular a source X is C0 on a detector placed 1 m from the source. When a metal sheet of thickness 5mm is placed between source and counter the count rate drops by 75%.
What is the value of the attenuation coefficient, μ, for this radiation and metal?
Chapter 9 Solutions
Introduction To Health Physics
Ch. 9 - Prob. 9.1PCh. 9 - Prob. 9.2PCh. 9 - Prob. 9.3PCh. 9 - Prob. 9.4PCh. 9 - Prob. 9.5PCh. 9 - Prob. 9.6PCh. 9 - Prob. 9.7PCh. 9 - Prob. 9.8PCh. 9 - Prob. 9.9PCh. 9 - Prob. 9.10P
Ch. 9 - Prob. 9.11PCh. 9 - Prob. 9.12PCh. 9 - Prob. 9.13PCh. 9 - A counting system has a background of 360 counts...Ch. 9 - Prob. 9.15PCh. 9 - Prob. 9.16PCh. 9 - Prob. 9.17PCh. 9 - Prob. 9.18PCh. 9 - Prob. 9.19PCh. 9 - Prob. 9.20PCh. 9 - Prob. 9.21PCh. 9 - Prob. 9.22PCh. 9 - Prob. 9.23PCh. 9 - Prob. 9.24PCh. 9 - Prob. 9.25PCh. 9 - Prob. 9.26PCh. 9 - Prob. 9.27PCh. 9 - Prob. 9.28PCh. 9 - Prob. 9.29PCh. 9 - Prob. 9.31PCh. 9 - Prob. 9.33PCh. 9 - Prob. 9.34PCh. 9 - Prob. 9.35PCh. 9 - Prob. 9.38PCh. 9 - Prob. 9.39PCh. 9 - Prob. 9.44P
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, physics and related others by exploring similar questions and additional content below.Similar questions
- Gamma rays typically have frequencies above 10 exahertz (or >1019 Hz). What is the corresponding wavelength in units of picometers (pm) of a gamma ray with a 3 * 1019 Hz? (1 pm = 10-12 m)?arrow_forwardQuestion 1. There are four factors: A, B, C, D. We assume that each replicate was considered as a block. Fill in the table as below and analyze the experiment with conclusions. Using a = 0.05. Treatment combination Rep 1 Rep 2 7.786 | 7.377014 6.789 | 6.398278 5.834 5.554411 A C D -1 a - b 2.341 2.28354 6.133 5.702366 3.669 | 3.608621 d ab ас 6.154 5.87312 ad 5.819| 5.550515 bc 12.887 12.62869 2.753 2.261361 4.451 4.411148 0.873 | 0.793026 4.678 | 4.259536 3.728 3.695787 bd cd abc abd bcd аcd 10.478 10.33168 abcd 1.722 | 1.365419 Table 1arrow_forwardA radioactive source is producing 1.50 MeV gamma rays. If two detectors are placed 4.00 m and 7.00 m away respectively, what is the ratio of the measured intensities of the near detector over the far detector (I2/I1)? Do NOT include units in your answer answer to 2 decimal places.arrow_forward
- A radiographic technique calls for 46 kVp and 28 mAs which results in an exposure of 278 µGy. What is the expected exposure if the technique is changed to 75 kVp and 14 mAs? Round your answer to the nearest whole number. Do not include units.arrow_forwardCalculate the CT numbers (HU) for the following tissues at given X-ray beam energies. Indicate whether the beam energy is suitable or not suitable for imaging of that specific tissue type. In the table below, the attenuation coefficients µ (m-1) are listed for each tissue for each of the beam energies. Beam Energy/Tissue 50keV 60keV 150keV Fat 20.17 18.75 14.25 Muscl 23.75 21.50 15.67 Compact Bones 81.45 60.44 28.42 Water 22.69 20.60 15.05arrow_forwardThe linear absorption coefficient of 1 MeV X-rays in water is 7.06 m-1. How many times will the radiation intensity decrease in a 19.6 cm thick water layer?arrow_forward
- A certain technique calls for 50 mA and 0.1 s at 65 kV. If we have an uncooperative patient and wish to reduce motion by using an exposure time of 1/60 s, what will the new mA value be? What is meant by the penetrating ability of an x-ray beam? How can the penetrating ability of a beam be changed?arrow_forwardThe point source Co-60 emits gamma with energies of 1.17 MeV and 1.33 MeV. Each of these energies emits the same number of photon particles. At a certain location, the flux that is read is 5.7 x 109 photons/cm2.s, what is the intensity or energy flux with units of J/m^2.minarrow_forwardA 3.0-MV transmission electron microscope has been in operation at Osaka University in Japan for several years. The higher-energy electrons allow for deeper sample penetration and extremely high resolution. What is the resolution limit for these electrons?arrow_forward
- question 4 pleasearrow_forwardA 192ir (r= 0.462 R. m2/Ci. h) source of strength 20 GBq is present as a wire of %3D length 3 m. What is the exposure rate, in R/h, 4 m away from this source if a person is standing: A)1 m from the left end of the source?( 4 m 1 m 2 m B) Directly in the center of the 3 m length? 4 m 1.5 m 1.5 marrow_forwardPlease solve in 30 minutearrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Modern PhysicsPhysicsISBN:9781111794378Author:Raymond A. Serway, Clement J. Moses, Curt A. MoyerPublisher:Cengage Learning
Principles of Physics: A Calculus-Based TextPhysicsISBN:9781133104261Author:Raymond A. Serway, John W. JewettPublisher:Cengage Learning
Modern Physics
Physics
ISBN:9781111794378
Author:Raymond A. Serway, Clement J. Moses, Curt A. Moyer
Publisher:Cengage Learning
Principles of Physics: A Calculus-Based Text
Physics
ISBN:9781133104261
Author:Raymond A. Serway, John W. Jewett
Publisher:Cengage Learning