Instructions for tasks

RADIATION

Instructions for tasks

Example 1. The distance from radioactive iodine to worker is 2 m (r₁), the worker obtained 0. 2 mber/week (D1). Find out obtaining dose (D₂) if the distance from radioactive iodine to worker will be 3 m (r ₂)? Give hygienic estimation of this dose (D₂).

Solution:

You may use the formula (D — dose; r — distance).

D₁ r₂²

F = —— = ---------- = 0. 2: D₂= 3²: 2² = 0. 2: D₂= 9: 4

D2 r ²

D₂= 0. 089 mber/week

Conclusion: obtaining dose = 0. 089 mber/week. This dose corresponds to hygienic standard (not more than 40 mber/week).

Example 2. Mr. R. works with a radioactive element during the 36 hours. The obtained dose of radiation is 0. 03 ber for hour. Your conclusion and recommendation about the condition of the work.

Solution:

1. 0. 03 ber/hour ´ 36 hours = 1. 08 ber/week.

The MPD* for week (36 hours) must be not more than 40 mber.

Conclusion: He receives big dose of radiation (MPD = 40 mber/week).

Recommendation: It is necessary additional preventive measures against ionizing radiation.

Example 3. Find out weekly exposuring dose of doctor who works with gamma iozining source, if the activity of this source is 5 mg. eq. rad. He works every week for 6 hours. The distance from the source is 40 cm.

Solution:

To find dose by the formula:

8, 4 x m x t

D = —————

r²

D— dose; m — activity; t — time; r — distance.

8, 4 x 5 mg. eq. rad. x 6 hours

D = ————— = 0. 157 roentgen (≈ ber)

40 cm ²

Conclusion: He receives more than normal dose of radiation (weekly MPD = 0, 04 ber = 40 mber). Recommendation: It is necessary additional preventive measures against ionizing radiation.

* MPD— Max Permissible Dose

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