Exempelsamling - KTH Particle and Astroparticle Physics

I wikipedia-sidan kan man läsa vidare:
“The fatal dose (LD50, the dose that leads to 50% risk of death) for acute radiation exposure is generally
about 4 Sv [5]. One Bq of 210 Po (i.e., an amount that produces one decay per second) causes a radiation
dose of 0.51 µSv if ingested 210 Po, and 2.5 µSv if inhaled [17] . Since 210 Po radiates 166 TBq per gram [17] , a
fatal 4 Sv dose can be caused by ingesting 8 MBq (200 microcurie), about 50 nanogram, or inhaling 1.6
MBq (40 microcurie), about 10 ng. One gram of 210 Po could thus in theory poison 100 millon people. In
addition to the acute effects, short-term radiation exposure carries a long-term risk of death from cancer
of approximately 8% per Sv [6].
In rats a dose of 1.45 MBq/kg (8.7 ng/kg) of 210 Po tends to cause death in about 30 days [18] . By this
measure, 210 Po is 400,000 times more toxic than hydrogen cyanide [7].
The maximum allowable body burden for ingested polonium is only 1,100 Bq (0.03 microcurie), which
is equivalent to a particle weighing only 6.8 picograms. The maximum permissible concentration for
airborne soluble polonium compounds is about 7,500 Bq/m 3 (2 × 10 -11 µCi/cm 3 ). The biological half-life
of polonium in humans is 30 to 50 days. [19]
Notably the death in 2006 of Alexander Litvinenko has been announced as probably due to
210 Po poisoning. [20] ”
Ex11:4 131 I antas ha molvikten 131 g 50 kg 131 I innehåller N 0I = 10/0,131 ·
6,022·10 23 kärnor. Pss innehåller 50 kg 60 Co N 0Co = 10/0,060 · 6,022·10 23
kärnor.
Effekten av den skyddande blydräkten:
För sönderfall från 131 I: 1 mm bly stoppar (1-e -0.1 ) = 9,5% av fotonerna.
Genomsnittligt bidrag blir då 0.905 · 365 keV = 330,3 keV ≈ 5,29·10 -14 J per
sönderfall.
Från 60 Co: 1 mm bly stoppar (1-e -0,05 ) ≈ 4,9 %.
Genomsnittligt bidrag: 0,951 · (1173 + 1332) keV ≈ 3,82·10 -13 J
Eftersom vi gör en överslagsberäkning och en timme