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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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 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.arrow_forwardA radioactive sample is analyzed to give a total of 4000 counts; background gives 250. How many counts were detected with one standard deviation?arrow_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 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_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_forwardAn alpha source was counted for 10 hours at a distance of 2 cm from a detector with an active face area of 500 mm2, If the resulting peak is integrated and found to have 2800 counts under the peak, what is the absolute activity of the source in Bq?arrow_forward
- What is the dose in mSv for 1.5 mGy of α exposure?arrow_forward✓ ON "O 2.75 MeV 0.511 MeV 0.511 MeV B, E= 1.73 MeV Eave = 0.721 Mev O MeVarrow_forwardThe rate of a simple enzyme reaction is given by the standard Michaelis–Menten equation: rate = Vmax [s]/([s] + KM) if the Vmax of an enzyme is 100 μmole/sec and the KM is 1 mM, at what substrate concentration is the rate 50 μmole/sec? Plot a graph of rate versus substrate (s) concentration for [s] = 0 to 10 mM. Convert this to a plot of 1/rate versus 1/[s]. Why is the latter plot a straight line?arrow_forward
- A 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_forwardIf the output is 24 mR / hour at 40 mAs, at 40 inches, what would the dose be per hour for 20 mAs (give answer in R)?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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