Nā nīnau hoʻohālike e kūkākūkā ana i nā ʻāpana radiation
He hanana kino ka radiation e pili ana i ka hoʻokuʻu ʻia ʻana o ka ikehu ma ke ʻano o nā ʻāpana a i ʻole nā ale. Loaʻa kēia hanana ma nā wahi āpau, mai nā kukuna o ka lā e hoʻomehana ai i ka honua a hiki i nā noi ʻoi aku ka ʻoihana o ka ʻenehana nukelea. He mea nui ke kūkākūkā ʻana i nā ʻāpana radiation ʻaʻole wale ma ka physics akā ma nā kahua o ke olakino a me ke kaiapuni. E kūkākūkā kēia ʻatikala i kekahi mau pilikia hoʻohālike a me nā kūkākūkā e pili ana i nā ʻāpana radiation e kōkua i ka hoʻomaopopo ʻana i ke kumuhana.
Hoʻolauna i ka Radiation
Ma mua o ko mākou luʻu ʻana i loko o nā pilikia hoʻohālike, he mea nui e hoʻomaopopo i nā kumu o nā ʻāpana radiation. Hiki ke hoʻokaʻawale ʻia ka radiation i ʻelua mau ʻāpana ākea: ka radiation ionizing a me ka radiation non-ionizing. Loaʻa i ka radiation ionizing ka ikehu e hoʻohui i nā ʻātoma, ʻo ia hoʻi, e hoʻohui a wehe paha i nā electrons mai nā ʻātoma a i ʻole nā molekala, a hoʻokomo pū i nā ʻano radiation e like me alpha, beta, a me nā kukuna gamma. ʻO ka radiation non-ionizing, ma ka ʻaoʻao ʻē aʻe, ʻaʻohe ikehu e hoʻohui i nā ʻātoma akā hiki ke hoʻomehana, e like me nā microwaves a me nā nalu lekiō.
Pāhawewe Alpha
He ʻāpana ka radiation Alpha i haku ʻia me ʻelua protons a me ʻelua neutrons (helium nuclei). No ka mea, he maikaʻi ka hoʻopiʻi ʻana o nā ʻāpana alpha a he nui hoʻi, he haʻahaʻa ko lākou mana komo a hiki ke hoʻōki ʻia e kahi ʻāpana pepa a i ʻole ka ʻili kanaka.
Laʻana Nīnau 1
Nīnau: Ua ʻike ʻia kahi kumu o ka radiation alpha e hoʻopuka i ka ikehu o 4 MeV. Inā paʻi kahi ʻāpana alpha i kahi ʻāpana pepa he 0,01 mm ka mānoanoa a ua omo piha ʻia, ehia ka ikehu i omo ʻia e ka pepa?
Kūkākūkā: ʻOiai ʻaʻole hiki i nā ʻāpana alpha ke komo i loko o ka pepa lahilahi, e omo ʻia ka ikehu a pau mai nā ʻāpana alpha e ka pepa. No laila, ua like ka ikehu i omo ʻia me ka ikehu i hoʻopuka ʻia, ʻo ia hoʻi ʻo 4 MeV.
Ka Pāhawewe Beta
ʻO ka radiation Beta he mau electrons wikiwiki kiʻekiʻe (beta minus) a i ʻole positrons (beta plus). ʻOi aku ka mana komo o nā ʻāpana Beta ma mua o nā ʻāpana alpha, akā hiki ke hoʻōki ʻia e kekahi mau milimita o ka mea paʻa, e like me ka alumini.
Laʻana Nīnau 2
Nīnau: Hoʻopuka kahi kumu radiation beta i nā ʻāpana me ka ikehu o 1 MeV. Inā paʻi kēia mau ʻāpana i kahi papa alumini 2 mm ka mānoanoa, e hoʻoholo inā hiki i nā ʻāpana beta ke komo i loko o ka mea.
Kūkākūkā: Ma keʻano laulā, hiki i nā ʻāpana beta me ka ikehu o 1 MeV ke komo i loko o kahi papa alumini he 1-2 mm ka mānoanoa. No laila, i kēia hihia, ua lawa ka mānoanoa o ka papa alumini e ālai i ka hapa nui o nā ʻāpana beta. Hiki i kekahi ke komo, akā e hoʻemi ʻia ko lākou ikehu i lawa ka liʻiliʻi o ko lākou hopena.
Ka hoʻolaha Gamma
ʻO ke kukuna gamma he kukuna electromagnetic e like me ke kukui a i ʻole nā kukuna X, akā me ka ikehu kiʻekiʻe. Loaʻa i kēia kukuna ka mana komo kiʻekiʻe loa a hiki ke komo i nā mea mānoanoa, akā hiki ke hoʻemi ʻia kona ikaika ma ka hoʻohana ʻana i nā mea kiʻekiʻe, e like me ke kēpau a i ʻole ka sima.
Laʻana Nīnau 3
Nīnau: Hoʻopuka kahi kumu gamma i nā photon gamma me ka ikehu o 0,5 MeV. Pehea ka mānoanoa o ke kēpau e pono ai e hoʻemi i ka hapalua o ka ikaika o ka radiation?
Kūkākūkā: Hoʻoholo ʻia ka emi ʻana o ka ikaika o ka radiation gamma e ke kānāwai exponential, i hōʻike ʻia e like me \(I = I_0 e^{-\mu x}\), kahi ʻo \(I\) ka ikaika radiation i koe, ʻo \(I_0\) ka ikaika mua, ʻo \(\mu\) ka coefficient attenuation o ka mea, a ʻo \(x\) ka mānoanoa o ka mea.
No ka radiation gamma me ka ikehu o 0,5 MeV, ʻo ka waiwai o \(\mu\) no ke kēpau ma kahi o 1,5 cm\(^{-1}\). Loaʻa iā mākou \(x\) i ka wā \(I = \frac{1}{2}I_0\):
\[ \frac{1}{2} = e^{-1,5x} \]
\[ \ln{\frac{1}{2}} = -1,5x \]
\[ x \approx \frac{-\ln{\frac{1}{2}}}{1,5} \approx \frac{0,693}{1,5} \approx 0,462 \text{ cm} \]
No laila, ma kahi o 0,46 kenimika o ke kēpau e hōʻemi ai i ka ikaika o ke kukuna gamma ma ka hapalua.
Nā hopena a me nā hopena
ʻO ka hoʻomaopopo ʻana i nā ʻano o nā ʻāpana radiation a pehea lākou e launa pū ai me nā mea like ʻole he mea nui ia no nā noi ʻenehana nukelea, ke olakino, a me ka palekana. ʻAʻole wale ka kūkākūkā ʻana o kēia mau pilikia e hāʻawi i kahi ʻike holoʻokoʻa o ke ʻano o ka hoʻopili ʻia ʻana o nā loina kumu akā e hōʻike pū ana hoʻi i ke koʻikoʻi o ka pale ʻana i ka radiation ma nā kūlana like ʻole.
Hiki i kēia ʻike ke lilo i mea hana koʻikoʻi no nā kānaka ʻepekema, nā ʻenekinia, a me nā loea olakino i ka hana ʻana i nā loiloi pilikia, ka hoʻolālā ʻana i ka pale ʻana i ka radiation, a me ka hōʻoia ʻana i ka palekana o nā ʻenehana e pili ana i ka radiation. Eia kekahi, he mea nui ka hoʻonaʻauao lehulehu e pili ana i nā pōʻino radiation a me ka hoʻēmi ʻana i nā pilikia i ke kaiāulu. Me ka hoʻomaopopo pono ʻana, hiki ke hoʻonui ʻia nā pono o ka ʻenehana radiation me ka hoʻēmi ʻana i kona mau hopena maikaʻi ʻole.
