Nā nīnau hoʻohālike e kūkākūkā ana i ka Alpha (α) Decay
Pendahuluan
ʻO ka palaho radioactive ke kaʻina hana e nalowale ai ka ikehu o nā nuclei atomika paʻa ʻole ma ka hoʻokuʻu ʻana i nā ʻāpana radiation. ʻO kekahi ʻano palaho radioactive i kūkākūkā pinepine ʻia ma ka physics ʻo ia ka palaho alpha (α). I ka palaho alpha, hoʻokuʻu kahi nucleus i kahi ʻāpana alpha, nona nā protons ʻelua a me nā neutrons ʻelua, e like me ka helium-4 nucleus. He mea koʻikoʻi ka hoʻomaopopo ʻana i ka palaho alpha i ka physics nuklea, kemika, a me nā kahua ʻē aʻe e pili ana i ka radioactivity. Ma kēia ʻatikala, e kūkākūkā mākou i kahi laʻana o ka palaho alpha, a ukali ʻia e kahi kūkākūkā e hoʻoikaika i ko mākou ʻike i kēia manaʻo.
Hoʻolauna iā Alpha Decay
Hoʻololi ka palaho Alpha i ka nucleus o ka ʻātoma palaho. Ke hoʻokuʻu kahi nucleus i kahi ʻāpana alpha, emi kona helu atomika i ʻelua a emi kona helu nuipa i ʻehā. Hiki ke hōʻike ʻia kēia ma o ka hoʻohālikelike laulā ma lalo nei:
\( _{Z}^{A}X \rightarrow _{Z-2}^{A-4}Y + _{2}^{4}\alpha \)
Ma hea:
– ʻO \( _{Z}^{A}X \) ka nucleus mua (ma mua o ka palaho ʻana).
– ʻO \( _{Z-2}^{A-4}Y \) ka nucleus hou (ma hope o ka palaho ʻana).
– ʻO \( _{2}^{4}\alpha \) ka ʻāpana alpha i hoʻokuʻu ʻia.
Hoʻohālikelike pilikia Alpha Decay
Nīnau 1:
Hoʻopōʻino ʻia ka Uranium-238 (\( _{92}^{238}U \)) ma o ka hoʻokuʻu ʻana o ka alpha. E hoʻoholo i ka mea hou i hana ʻia ma hope o hoʻokahi hoʻopōʻino alpha!
Kūkākūkā:
No ka hoʻoponopono ʻana i kēia pilikia, e hoʻohana mākou i nā loina kumu o ka palaho alpha.
1. E kākau i ka hopena palaho alpha:
\( _{92}^{238}U \rightarrow _{Z}^{A}Y + _{2}^{4}\alpha \)
2. E hoʻoholo i nā waiwai Z a me A no ka mea hou:
ʻOiai he helu atomika 2 a he helu nuipa 4 ko nā ʻāpana alpha, hiki iā mākou ke helu:
– Ka helu ʻātoma o ka mea hou, \( Z = 92 – 2 = 90 \)
– Ka helu nuipa o ka mea hou, \( A = 238 – 4 = 234 \)
3. E huli i ka mea me ka helu atomika 90:
Wahi a ka papa ʻaina manawa, ʻo ka mea me ka helu atomika 90 ʻo Thorium (Th).
No laila, ʻo ka mea hou i hoʻokumu ʻia ʻo Thorium-234 (\( _{90}^{234}Th \)). ʻO ka hopena piha penei:
\( _{92}^{238}U \rightarrow _{90}^{234}Th + _{2}^{4}\alpha \)
Nīnau 2:
Hoʻopōʻino ʻo Radium-226 (\( _{88}^{226}Ra \)) i Radon-222 ma hope o ka hoʻokuʻu ʻana i kahi ʻāpana alpha. ʻEhia ka nui o ka ikehu i hoʻokuʻu ʻia ma kēia kaʻina hana? (Manaʻo i nā nui o nā ʻāpana liʻiliʻi a hoʻohana i nā nui atomika maʻamau: \( ^{226}Ra = 226.025402 \), \( ^{222}Rn = 222.017570 \), a me \( ^{4}He = 4.002602 \); 1 anakahi nui atomika \( \approx \) 931 MeV/c²)
Kūkākūkā:
Hiki ke helu ʻia ka ikehu i hoʻokuʻu ʻia i ka wā o ka palaho alpha mai ka ʻokoʻa o ka nuipa ma waena o ka nucleus mua a me ka huahana hope loa a me ka ʻāpana alpha, i hoʻololi ʻia i ikehu me ka hoʻohana ʻana i ka hoohalike E=mc².
1. E helu i ka ʻokoʻa o ka nuipa ma mua a ma hope o ka palaho ʻana:
Nuipaʻa ma mua o ka palaho (Radium-226):
\( m_{\kikokikona{ma mua}} = 226.025402 \)
Nui ma hope o ka palaho (Radon-222) a me ka ʻāpana alpha:
\( m_{\text{after}} = 222.017570 + 4.002602 = 226.020172 \)
ʻOkoʻa nuipa:
\( \Delta m = 226.025402 – 226.020172 = 0.005230 \) u
2. E hoʻololi i ka ʻokoʻa nuipa i ikehu:
Ikehu i hoʻokuʻu ʻia, \( E = \Delta m \times 931 \) MeV
\( E = 0.005230 \times 931 \) MeV
\( E \approx 4.866 \) MeV
No laila, ʻo ka ikehu i hoʻokuʻu ʻia i ka palaho alpha o Radium-226 i Radon-222 ma kahi o 4.866 MeV.
Nā hopena a me nā noi o ka Alpha Decay
He nui nā hopena a me nā noi o ka palaho Alpha i ka ʻepekema a me ka ʻenehana. ʻO kekahi o kēia mau mea:
1. Ka Hoʻopaʻa ʻana ma o ke Radiometric: Hoʻohana kēia ʻano hana i ka palaho radioactive e hoʻoholo ai i ka makahiki o kahi mea. ʻO ka hoʻopaʻa ʻana ma o ke Uranium-Lead kahi laʻana kahi e kōkua ai ka palaho alpha i ka hoʻoholo ʻana i ka makahiki o nā pōhaku a me nā minelala.
2. Lapaʻau Kanesa: Hoʻohana ʻia kekahi mau isotopes e hoʻopuka ana i nā ʻāpana alpha i ka mālama ʻana i ka maʻi kanesa. He pōkole ka laulā o nā ʻāpana Alpha a he nui ka ikehu, hiki ke pepehi i nā hunaola kanesa ma ka wahi i kuhikuhi ʻia me ka ʻole o ka hōʻino ʻana i nā ʻiʻo olakino a puni.
3. Palekana Nukelea: He mea nui ka hoʻomaopopo ʻana i ka palaho alpha i ka hoʻolālā a me ka mālama ʻana i nā mea nukelea, ʻoiai hiki i kekahi mau isotopes alpha-emitting ke lilo i mea weliweli loa inā hanu ʻia a ʻai ʻia paha.
4. Nā Mea ʻIke Uahi: Hoʻohana kekahi mau mea ʻike uahi i nā isotopes e hoʻopuka i nā ʻāpana alpha e ʻike i ka uahi i loko o kahi lumi. Hoʻohui nā ʻāpana alpha i ka ea i loko o ka mea ʻike, a i ka wā e hoʻopilikia ai ka uahi i kēia kaʻina hana, hoʻāla ʻia kahi alarm.
Ka hopena
ʻO ka palaho Alpha kahi ʻano palaho radioactive e pāʻani ana i kahi kuleana koʻikoʻi i nā ʻano ʻepekema like ʻole a me nā noi ʻenehana. Ma ka hoʻomaopopo ʻana i nā hiʻohiʻona palaho alpha, hiki iā mākou ke hoʻomaopopo maikaʻi i nā kaʻina hana nukelea e hoʻokumu ai i kēia palaho a me kona mau hopena ikehu. ʻOiai ʻo ka palaho alpha e pili ana i nā loli maʻalahi i ka helu nuipa a me ka helu atomika, hiki i kona hopena ma ko kākou honua ke koʻikoʻi, ʻoiai ma ke ʻano o ka mālama manawa geological, nā noi lapaʻau, a me ka palekana. Ke hoʻomau nei ke aʻo ʻana i ka palaho alpha i ka holomua, e wehe ana i nā ʻaoʻao hou i ka noiʻi a me nā noi ʻenehana.
