Poʻomanaʻo: Laʻana o nā nīnau kūkākūkā no ka palaho radioactive
ʻO ka palaho radioactive ke kaʻina hana e nalowale ai ka ikehu o nā nuclei atomika paʻa ʻole ma o ka hoʻopuka ʻana i ka radiation. Hiki i kēia kaʻina hana ke hana i nā mea hou a paʻa. E kūkākūkā kēia ʻatikala i kekahi mau laʻana o nā pilikia i loaʻa pinepine i nā haʻawina physics e pili ana i ka palaho radioactive.
Pendahuluan
He hanana kūlohelohe ka Radioactivity i ʻike ʻia e Henri Becquerel i ka makahiki 1896. Ua hoʻomohala hou ʻia e ka wahine ʻepekema kaulana ʻo Marie lāua ʻo Pierre Curie. Hana ʻia ka Radioactivity i ka wā e hoʻokuʻu ai kahi nucleus atomika i nā ʻāpana a i ʻole ka radiation electromagnetic, e hoʻololi ana i kēlā mea i mea ʻē aʻe. He mea nui kēia kaʻina hana ma nā ʻano he nui e like me ka lāʻau lapaʻau, ka mana nukelea, a me ka ʻeli ʻana.
Nā Kumu o ka Palaho Radioactive
Hahai ka palaho radioactive i ke kānāwai o ka palaho exponential. Loaʻa i kēlā me kēia mea radioactive kahi hapalua ola, ʻo ia ka manawa e pono ai no ka hapalua o nā nuclei i loko o kahi hāpana e palaho. ʻO kekahi mau ʻano palaho radioactive e komo pū me ka alpha, beta, a me ka gamma decay.
1. Alpha Decay: ʻO ka hoʻokuʻu ʻia ʻana o kahi ʻāpana alpha, nona nā proton ʻelua a me nā neutron ʻelua, e hōʻemi ana i ka helu nuipa (A) ma 4 a me ka helu atomika (Z) ma 2 o ka ʻātoma makua.
2. Beta Decay: I ka beta decay, loli kahi neutron i loko o ka nucleus i proton me ka hoʻokuʻu ʻia ʻana o kahi ʻāpana beta (electron a positron paha). Noho like ka helu nuipa, akā piʻi ka helu atomika (beta minus) a emi paha (beta plus) ma 1.
3. Kukui Gamma: ʻO kēia kukuna kahi ʻano o ka ikehu electromagnetic i hoʻokuʻu ʻia me ka ʻole o ka hoʻololi ʻana i ka helu o ka nuipa a i ʻole nā protons i loko o ka nucleus atomika.
Nā Nīnau Laʻana a me ke Kūkākūkā
E nānā kākou i kekahi mau laʻana o ka palaho radioactive e hoʻomaopopo maikaʻi i kēia manaʻo.
Laʻana Nīnau 1: Alpha Decay
Nīnau: Ke hele nei kahi hāpana o Uranium-238 i ka palaho alpha. E kākau i ka hopena palaho a kuhikuhi i nā mea i hana ʻia e ka palaho.
Kūkākūkā:
Hoʻopilikia ka Uranium-238 (U-238) i ka palaho alpha ma ka hoʻokuʻu ʻana i nā ʻāpana alpha. Hiki ke kākau ʻia ka hopena palaho alpha penei:
\[ ^{238}_{92}U \rightarrow ^{234}_{90}Th + ^{4}_{2}He \]
Hoʻololi ʻo Uranium-238 i Thorium-234 (Th-234) ma hope o ka hoʻokuʻu ʻana i kahi ʻāpana alpha i haku ʻia me ʻelua protons a me ʻelua neutrons. E emi ana ka helu nuipa ma 4, a e emi ana ka helu atomika ma 2.
Laʻana Nīnau 2: Beta Decay
Nīnau: Ke hele nei kahi hāpana o Carbon-14 i ka palaho beta. E kākau i ka hopena palaho a kuhikuhi i nā mea i hana ʻia e ka palaho.
Kūkākūkā:
Ke hele nei ke kalapona-14 i ka palaho beta, kahi e loli ai ka neutron i proton, e hoʻokuʻu ana i kahi electron a me kahi antineutrino. ʻO ke ʻano o ka palaho:
\[ ^{14}_{6}C \rightarrow ^{14}_{7}N + ^{0}_{-1}e + \overline{\nu}_e \]
Hoʻololi ke kalapona-14 i ka naikokene-14. ʻAʻole like ka nui o ke kaumaha, akā piʻi ka helu ʻātoma ma ka 1 ma muli o ka hoʻololi ʻana o nā neutron i nā proton.
Laʻana Nīnau 3: Hapa-Ola
Nīnau: He 3.8 mau lā ka hapalua o ke ola o kahi hāpana o Radon-222. Inā hoʻomaka mākou me kahi hāpana 80-gram, ehia ka nui o ke kaumaha e koe ma hope o 11.4 mau lā?
Kūkākūkā:
ʻO ka manawa 11.4 lā he ʻekolu manawa o ka hapalua ola o Radon-222 (11.4 lā / 3.8 lā no kēlā me kēia hapalua ola = 3 hapalua ola). Ma hope o kēlā me kēia hapalua ola, e palaho ana ka hapalua o ka hāpana. No laila, hana mākou i ka helu ʻana penei:
– Ma hope o 3.8 mau lā, ʻo ke kaumaha i koe: \( \frac{80}{2} = 40 \) grams.
– Ma hope o 7.6 mau lā (2 x 3.8 mau lā), ʻo ke kaumaha i koe: \( \frac{40}{2} = 20 \) grams.
– Ma hope o 11.4 mau lā (3 x 3.8 mau lā), ʻo ke kaumaha i koe: \( \frac{20}{2} = 10 \) grams.
No laila, ma hope o 11.4 mau lā, e koe ana he 10 grams o Radon-222.
Laʻana Nīnau 4: Ka Palaho Hui Pū ʻana
Nīnau: I loko o kahi kaulahao palaho, lilo ʻo Uranium-238 i Lead-206 ma o kekahi mau pae palaho, me nā palaho alpha a me beta. E helu i ka nui o nā palaho alpha a me beta e hana ʻia ma kēia kaʻina hana.
Kūkākūkā:
Hoʻomaka ke kaʻina hana mai Uranium-238 (helu nuipa 238, helu atomika 92) a i Lead-206 (helu nuipa 206, helu atomika 82). No ka hoʻoholo ʻana i ka helu o nā palaho, pono mākou e ʻimi i ka ʻokoʻa ma waena o ka helu nuipa a me ka helu atomika:
Hoʻololi i ka helu nuipaʻa: 238 – 206 = 32 (Hoʻemi kēlā me kēia palaho alpha i ka helu nuipaʻa ma 4)
Ka helu o nā palaho alpha: 32 / 4 = 8
Hoʻololi i ka helu atomika: 92 – 82 = 10 (Hoʻemi kēlā me kēia palaho alpha i ka helu atomika ma 2, ʻoiai ʻo ka palaho beta e hoʻonui i ka helu atomika ma 1)
Ua ʻike mākou he 8 mau palaho alpha (e hōʻemi ana i ka helu atomika e 16). No ka hoʻokō ʻana i ka hōʻemi holoʻokoʻa o 10, pono ʻia he 6 mau palaho beta (e hoʻonui ana i ka helu atomika e 6).
No laila, aia he 8 mau palaho alpha a me 6 mau palaho beta i ka hoʻololi ʻana o Uranium-238 i Lead-206.
Ka hopena
He kaʻina hana koʻikoʻi ka palaho radioactive e hōʻike ana pehea e hoʻāʻo ai nā mea paʻa ʻole e hoʻopaʻa ma o ka hoʻokuʻu ʻana i ka ikehu. ʻO ka hoʻomaopopo ʻana i nā manaʻo o ka palaho alpha, beta, a me gamma, a me ka hoʻopili ʻana o nā hapalua ola, he mea nui ia no ka hoʻomaopopo ʻana i kēia hanana. Hōʻike ka pilikia laʻana ma luna pehea e hiki ai ke hoʻopili ʻia kēia mau manaʻo i nā helu palaho radioactive.
Ma ke aʻo ʻana a me ka hoʻomaopopo ʻana i kēia mau kaʻina hana, ʻaʻole wale mākou e loaʻa i nā ʻike hohonu i ke ʻano kino o ke ao holoʻokoʻa, akā, ʻo kā lākou hoʻohana ʻana i nā ʻenehana hou i hoʻohana ʻia ma nā ʻano like ʻole.
