Introduction To Health Physics
5th Edition
ISBN: 9780071835275
Author: Johnson, Thomas E. (thomas Edward), Cember, Herman.
Publisher: Mcgraw-hill Education,
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Chapter 9, Problem 9.7P
To determine
How long the sample must be counted in order to be within ±10% of the true activity at the 95% confidence level
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Estimate the exposure rate 2 m from 4 Ci sources of 57Co,22Na,65Zn?Exposure Rate constant for 57Co=0.9 (R.cm2) / (hr.mCi)Exposure Rate constant for 22Na =12 (R.cm2) / (hr.mCi)Exposure Rate constant for 65Zn =2.7 (R.cm2) / (hr.mCi)
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.
A Co-60 source gives a gamma dose rate of 120 μSv/h at 2.2 m away. At what distance (in
meter) will the dose rate be 59 µSv/h? Provide your answer with 1 decimal place.
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
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- A worker will need to conduct a repair to a pipe containing radioactive waste. The pipe is 10 m long, and the worker will need to be standing 50 cm from the pipe. A remote detector was used to take a reading of 1.5 R/hr at 3 m from the pipe. a) What is the dose rate at the work position? b) If the worker's dose limit is 30 rad, how long will he have to complete the work? Assume that there is no dose from approaching and leaving the work location.arrow_forward27. A shielded vial with a 1-mm thick lead shield contains Tc. If A. 11.8 mR/hr В. 23.5 mR/hr C. 47 mR/hr D. 94 mR/hr the unshielded sample yielded an exposure rate of 188 mR/hr, what will the exposure rate be from the shielded vial? (The lead HVL for Tc is 0.25 mm.) 28. If "Co gives an exposure rate of 38 R/hr at 2 m, at least how А. 2 В. 3 many HVLS of concrete shielding are required to reduce this exposure to below 2 R/hr at the same distance? (The concrete HVL for "Co is 6.2 cm.) С. 4 D. 5arrow_forward29. A shielded vial with a 0.1-mm thick lead shield contains 11. This A. 8 mR/hr B. 1 mR/hr shielded sample yields an exposure rate of 0.25 mR/hr at a distance of 3 cm. What will the exposure rate be at the same distance when the shield is removed? (The lead HVL for 125I is C. 0.5 mR/hr D. 0.25 mR/hr 0.02 mm.) 30. A shielded vial with a 4.0-mm thick lead shield contains "F. This shielded sample yields an exposure rate of 6 mR/hr at a distance of 1 cm. What will the exposure rate be at the same distance when the shield is removed? (The lead HVL for F is 4.0 mm.) A. 12 mR/hr B. 6 mR/hr C. 3 mR/hr D. 1.5 mR/hrarrow_forward
- ✓ ON "O 2.75 MeV 0.511 MeV 0.511 MeV B, E= 1.73 MeV Eave = 0.721 Mev O MeVarrow_forwardA beam of 5.0 MeV alpha particles (q-2e) has a cross-sectional area of 1.50 cm2. It is incident on flesh (p-950 kg/m³) and penetrates to a depth of 0.70 mm. a) What dose in Gy does the beam provide to the flesh in a time of 3.0 s? b) What effective dose does it provide? Assume the beam to carry a current of 2.50 x 109 A and to have QF - 14.arrow_forwardFor a given detection system used to measure 14c, the background counting rate for a single blank of a given sample composition was determined to be 25 cpm for 30 minutes. The gross counting efficiency for 14C in this sample composition is 0.82 counts per decay. The counting interval for actual samples will be 10 minutes. Assume the background counting data are random and normally distributed, and that type I and type Il error probabilities ( and ) are equal to 0.05. 20) What is the lower limit of detection for 14C in this sample composition? А.3.9 сpm В.4.5 сpm С.6.3 сpm D.11.3 сpm Е.24.3 сpmarrow_forward
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