Kafin fasahar sau uku, wato, game da gano aikin rediyo na wucin gadi
Daga lokaci zuwa lokaci a cikin tarihin ilimin kimiyyar lissafi akwai shekaru masu "ban mamaki" lokacin da ƙoƙarin haɗin gwiwa na yawancin masu bincike ya haifar da jerin abubuwan ganowa. Haka ya kasance a shekarar 1820, shekarar wutar lantarki, 1905, shekarar ban mamaki na takardun Einstein guda hudu, 1913, shekarar da ke da alaka da nazarin tsarin kwayar zarra, daga karshe, 1932, lokacin da jerin binciken fasaha da ci gaba a cikin An halicci makamashin nukiliya. kimiyyar lissafi.
sababbin ma'aurata
Irina, babbar 'yar Marie Skłodowska-Curie da Pierre Curie, an haife shi a Paris a 1897 (1). Har zuwa shekaru goma sha biyu, ta girma a gida, a cikin wata karamar "makarantar" da manyan masana kimiyya suka kirkiro don 'ya'yanta, wanda akwai dalibai kusan goma. Malaman su ne: Marie Sklodowska-Curie (physics), Paul Langevin (ilimin lissafi), Jean Perrin (Chemistry), da kuma ilimin ɗan adam uwayen ɗaliban ne suka koyar da su. Yawancin darussa suna faruwa a gidajen malamai, yayin da yara suka yi karatun physics da chemistry a dakunan gwaje-gwaje na gaske.
Don haka, koyar da ilimin lissafi da sinadarai shine samun ilimi ta hanyar ayyuka masu amfani. Kowane gwaji mai nasara ya faranta wa matasa masu binciken farin ciki. Waɗannan gwaje-gwaje ne na gaske waɗanda dole ne a fahimta kuma a yi su a hankali, kuma yaran da ke cikin dakin gwaje-gwaje na Marie Curie dole ne su kasance cikin tsari mai kyau. Hakanan dole ne a sami ilimin ka'idar. Hanyar, kamar yadda makomar daliban wannan makaranta ta nuna, wadanda daga baya suka zama ƙwararrun masana kimiyya, sun kasance masu tasiri.
2. Frederic Joliot (hoto Harcourt)
Bugu da ƙari, kakan mahaifin Irena, likita, ya ba da lokaci mai yawa ga jikanyar mahaifinsa marayu, yana jin daɗi da kuma ƙara ilimin kimiyyar halitta. A 1914, Irene ta sauke karatu daga majagaba Collège Sévigné kuma ta shiga sashin ilimin lissafi da kimiyya a Sorbonne. Wannan ya zo daidai da farkon yakin duniya na farko. A 1916 ta shiga mahaifiyarta kuma tare suka shirya sabis na rediyo a cikin Red Cross ta Faransa. Bayan yakin, ta sami digiri na farko. A cikin 1921, an buga aikinta na farko na kimiyya. Ya sadaukar da kai ga tantance adadin atomic na chlorine daga ma'adanai daban-daban. A cikin ayyukanta na gaba, ta yi aiki tare da mahaifiyarta, tana magance aikin rediyo. A cikin takardar digirinta na digiri, wanda aka kare a 1925, ta yi nazarin alpha barbashi da polonium ke fitarwa.
Frederic Joliot ne adam wata an haife shi a shekara ta 1900 a birnin Paris (2). Tun yana dan shekara takwas ya halarci makaranta a So, ya zauna a makarantar kwana. A lokacin ya fi son wasanni fiye da karatu, musamman kwallon kafa. Daga nan sai ya yi bi-biyu ya shiga manyan makarantu guda biyu. Kamar Irene Curie, ya rasa mahaifinsa da wuri. A 1919 ya ci jarrabawa a École de Physique et de Chemie Industrielle de la Ville de Paris (Makarantar Masana'antu Physics da Masana'antu Chemistry na birnin Paris). Ya sauke karatu a 1923. Farfesansa, Paul Langevin, ya koyi iyawa da halayen Frederick. Bayan watanni 15 na aikin soja, bisa umarnin Langevin, an nada shi mataimakiyar dakin gwaje-gwaje na sirri ga Marie Skłodowska-Curie a Cibiyar Radium tare da tallafi daga Gidauniyar Rockefeller. A can ya sadu da Irene Curie, kuma a 1926 matasa suka yi aure.
Frederick ya kammala karatun digirinsa na digiri a kan ilimin electrochemistry na abubuwan rediyoaktif a cikin 1930. Ba da jimawa ba, ya riga ya mai da hankali ga binciken matarsa, kuma bayan kare Frederick na digiri na uku, sun riga sun yi aiki tare. Ɗaya daga cikin muhimman nasarorin da suka samu na farko shi ne shirye-shiryen polonium, wanda shine tushen karfi na alpha particles, watau. helium nuclei.(24Shi). Sun fara ne daga wani matsayi mai gata, domin Marie Curie ce ta ba wa 'yarta babban kaso na polonium. Lew Kowarsky, abokin haɗin gwiwar su daga baya, ya kwatanta su kamar haka: Irena "kwararriyar ƙwararriyar fasaha ce", "ta yi aiki sosai da kyau kuma a hankali", "ta fahimci abin da take yi sosai." Mijinta yana da "mafi kyan gani, mafi girman tunanin." "Sun yi daidai da juna kuma sun sani." Daga ra'ayi na tarihin kimiyya, mafi ban sha'awa a gare su shine shekaru biyu: 1932-34.
Sun kusan gano neutron
"Kusan" yana yin babban bambanci. Sun koyi game da wannan gaskiya mai ban tausayi ba da daɗewa ba. A cikin 1930 a Berlin, Jamusawa biyu - Walter Bothe i Hubert Becker ne adam wata – yayi nazari kan yadda hasken zarra ke aiki lokacin da barbashi na alpha suka yi masa bam. Garkuwar Beryllium (49Be) lokacin da aka jefa bam tare da ɓangarorin alpha suna fitar da matsanancin ratsawa da radiation mai ƙarfi. A cewar masu gwajin, wannan radiation dole ne ya kasance mai ƙarfi na lantarki.
A wannan matakin, Irena da Frederick sun magance matsalar. Tushen su na alpha barbashi shine mafi ƙarfi da aka taɓa samu. Sun yi amfani da ɗakin gajimare don lura da samfuran dauki. A ƙarshen Janairu 1932, sun ba da sanarwar a bainar jama'a cewa hasken gamma ne ya fitar da protons masu ƙarfi daga wani abu mai ɗauke da hydrogen. Har yanzu ba su fahimci abin da ke hannunsu da abin da ke faruwa ba.. Bayan karantawa James Chadwick ne adam wata (3) Nan da nan a Cambridge ya fara aiki, yana tunanin cewa ba gamma radiation ba ne, amma neutrons da Rutherford ya annabta shekaru da yawa kafin. Bayan gwaje-gwaje da yawa, sai ya gamsu da lura da neutron kuma ya gano cewa yawansa yana kama da na proton. A ranar 17 ga Fabrairu, 1932, ya gabatar da bayanin kula ga mujallar Nature mai take "The Yiwuwar Kasancewar Neutron."
A zahiri neutron ne, ko da yake Chadwick ya yi imanin cewa neutron ya kasance na proton da electron. Sai kawai a cikin 1934 ya gane kuma ya tabbatar da cewa neutron wani abu ne na farko. Chadwick ya sami lambar yabo ta Nobel a Physics a 1935. Duk da fahimtar cewa sun rasa wani muhimmin bincike, Joliot-Curies sun ci gaba da bincike a wannan yanki. Sun fahimci cewa wannan amsa ta haifar da hasken gamma ban da neutrons, don haka suka rubuta amsawar nukiliya:
, inda Ef shine makamashin gamma-quantum. An yi irin wannan gwaje-gwaje da 919F.
An rasa buɗewa kuma
Bayan 'yan watanni kafin gano positron, Joliot-Curie yana da hotunan, tare da wasu abubuwa, wata hanya mai lankwasa, kamar dai na'urar lantarki ne, amma tana karkatar da sabanin hanyar lantarki. An dauki hotunan ne a wani dakin hazo da ke cikin filin maganadisu. A kan haka, ma'auratan sun yi magana game da electrons da ke tafiya ta hanyoyi biyu, daga tushe da kuma tushen. A haƙiƙa, waɗanda ke da alaƙa da alkiblar “zuwa tushen” sun kasance positrons, ko ingantattun electrons waɗanda ke motsawa daga tushen.
A halin yanzu, a Amurka a ƙarshen lokacin rani na 1932. Karl David Anderson (4), ɗan baƙi Sweden, ya yi nazarin hasken sararin samaniya a cikin ɗakin gajimare a ƙarƙashin tasirin filin maganadisu. Hasken sararin samaniya yana zuwa duniya daga waje. Anderson, don tabbatar da alkibla da motsi na barbashi, a cikin ɗakin ya wuce ɓangarorin ta farantin ƙarfe, inda suka rasa wasu kuzari. A ranar 2 ga Agusta, ya ga wata hanya, wanda babu shakka ya fassara a matsayin tabbataccen electron.
Ya kamata a lura cewa Dirac ya riga ya annabta wanzuwar ka'idar irin wannan barbashi. Duk da haka, Anderson bai bi kowace ka'ida ba a cikin bincikensa na haskoki na sararin samaniya. A cikin wannan mahallin, ya kira bincikensa da gangan.
Bugu da ƙari, Joliot-Curie ya haƙura da wata sana'a da ba za a iya musantawa ba, amma ya ci gaba da bincike a wannan yanki. Sun gano cewa gamma-ray photons na iya ɓacewa kusa da tsakiya mai nauyi, suna samar da nau'i-nau'i na electron-positron, a fili bisa ga sanannen dabarar Einstein E = mc2 da ka'idar kiyaye makamashi da kuzari. Daga baya, Frederick da kansa ya tabbatar da cewa akwai wani tsari na bacewar na'urar lantarki-positron, wanda ya haifar da adadin gamma guda biyu. Baya ga positrons daga nau'i-nau'i na electron-positron, suna da positrons daga halayen nukiliya.
5. Taron Solvay na bakwai, 1933
Zaune a layi na gaba: Irene Joliot-Curie (na biyu daga hagu),
Maria Skłodowska-Curie (na biyar daga hagu), Lise Meitner (na biyu daga dama).
aikin rediyo na wucin gadi
Gano aikin rediyo na wucin gadi ba aikin nan take ba. A cikin Fabrairu 1933, ta hanyar bombarding aluminum, fluorine, sa'an nan sodium tare da alpha barbashi, Joliot samu neutrons da ba a sani ba isotopes. A cikin Yuli 1933, sun sanar da cewa, ta hanyar haskaka aluminum tare da alpha barbashi, sun lura ba kawai neutrons, amma kuma positrons. A cewar Irene da Frederick, positrons a cikin wannan amsawar nukiliya ba za su iya samuwa ba sakamakon samuwar nau'i-nau'i-nau'i-nau'i na electron-positron, amma dole ne su fito daga tsakiya na atomic.
Taron Solvay na bakwai (5) ya gudana a Brussels a ranar 22-29 ga Oktoba, 1933. An kira shi "Tsarin da Kaddarorin Atomic Nuclei". Masana kimiyya 41 ne suka halarci taron, ciki har da fitattun masana a wannan fanni a duniya. Joliot ya ba da rahoton sakamakon gwaje-gwajen da suka yi, inda ya bayyana cewa hasken boron da aluminum tare da hasken alpha yana samar da ko dai neutron tare da positron ko proton.. A wannan taro Lisa Meitner Ta ce a gwaje-gwajen da aka yi da aluminum da fluorine, ba ta samu sakamako iri daya ba. A cikin fassarar, ta ba ta raba ra'ayi na ma'aurata daga Paris game da yanayin nukiliya na asalin positrons. Duk da haka, lokacin da ta koma aiki a Berlin, ta sake yin waɗannan gwaje-gwaje, kuma a ranar 18 ga Nuwamba, a cikin wata wasika zuwa ga Joliot-Curie, ta yarda cewa yanzu, a ra'ayinta, positrons suna fitowa daga tsakiya.
Bugu da kari, wannan taro Francis Perrin, takwarorinsu kuma abokin kirki daga Paris, sun yi magana game da batun positrons. Daga gwaje-gwajen an san cewa sun sami ci gaba da bakan na positron, kama da bakan beta a cikin lalatawar rediyoaktif na halitta. Ci gaba da nazari kan makamashin positrons da neutrons Perrin ya kai ga yanke shawarar cewa ya kamata a bambanta fitar da hayaki guda biyu a nan: na farko, fitar da neutrons, tare da samuwar tsakiya mara tsayayye, sannan kuma fitar da positrons daga wannan tsakiya.
Bayan taron Joliot ya dakatar da waɗannan gwaje-gwajen kusan watanni biyu. Kuma a sa'an nan, a watan Disamba 1933 Perrin ya buga ra'ayinsa game da al'amarin. A lokaci guda kuma a watan Disamba Enrico Fermi ya gabatar da ka'idar lalata beta. Wannan ya zama tushen ka'idar don fassarar abubuwan kwarewa. A farkon 1934, ma'auratan daga babban birnin Faransa sun sake yin gwajin su.
A dai-dai ranar 11 ga watan Janairu, ranar Alhamis da yamma, Frédéric Joliot ya ɗauki foil na aluminum ya jefar da shi da barbashi na alpha na tsawon mintuna 10. A karon farko, ya yi amfani da injin Geiger-Muller don ganowa, ba ɗakin hazo ba, kamar da. Ya yi mamakin ganin cewa, yayin da yake cire tushen alpha particles daga cikin foil, ƙidayar positrons bai tsaya ba, ƙidayar ta ci gaba da nuna su, kawai adadinsu ya ragu sosai. Ya ƙaddara rabin rayuwar ya zama mintuna 3 da sakan 15. Sa'an nan kuma ya rage kuzarin ƙwayoyin alpha da ke faɗowa akan foil ta hanyar sanya birki na gubar a kan hanyarsu. Kuma ya sami ƙarancin positrons, amma rabin rayuwar ba ta canza ba.
Sannan ya sanya boron da magnesium zuwa gwaje-gwaje iri ɗaya, kuma ya sami rabin rai a cikin waɗannan gwaje-gwajen na mintuna 14 da mintuna 2,5, bi da bi. Bayan haka, an gudanar da irin waɗannan gwaje-gwajen da hydrogen, lithium, carbon, beryllium, nitrogen, oxygen, fluorine, sodium, calcium, nickel da azurfa - amma bai lura da wani abu mai kama da aluminum, boron da magnesium ba. Ma'aunin Geiger-Muller ba ya bambance tsakanin ɓangarorin da aka caje masu inganci da mara kyau, don haka Frédéric Joliot ya kuma tabbatar da cewa a zahiri yana mu'amala da na'urorin lantarki masu inganci. Har ila yau, fannin fasaha yana da mahimmanci a cikin wannan gwaji, watau, kasancewar tushen tushe mai karfi na alpha barbashi da kuma amfani da ma'aunin abin da aka caje, kamar ma'aunin Geiger-Muller.
Kamar yadda aka bayyana a baya ta hanyar Joliot-Curie biyu, positrons da neutrons ana fitar da su lokaci guda a cikin canjin makaman nukiliya da aka gani. Yanzu, bin shawarwarin Francis Perrin da karanta la'akarin Fermi, ma'auratan sun kammala cewa matakin farko na makaman nukiliya ya haifar da ƙwayar cuta mara tsayayye da neutron, sannan beta tare da lalata waccan tsakiya mara ƙarfi. Don haka suna iya rubuta martani kamar haka:
Joliots sun lura cewa sakamakon isotopes na rediyoaktif yana da gajeriyar rabin-rai don wanzuwa a cikin yanayi. Sun bayyana sakamakonsu ne a ranar 15 ga Janairu, 1934, a wata kasida mai suna "Sabon Nau'in Radiyo". A farkon Fabrairu, sun yi nasarar gano phosphorus da nitrogen daga halayen biyu na farko daga ƙananan adadin da aka tattara. Ba da daɗewa ba an yi annabci cewa za a iya samar da ƙarin isotopes na rediyoaktif a cikin halayen bam na nukiliya, kuma tare da taimakon protons, deuterons da neutrons. A cikin Maris, Enrico Fermi ya yi fare cewa ba da daɗewa ba za a aiwatar da irin waɗannan halayen ta hanyar amfani da neutrons. Nan da nan ya ci fare da kansa.
An ba Irena da Frederick lambar yabo ta Nobel a fannin ilmin sinadarai a shekarar 1935 saboda "haɗuwar sabbin abubuwa na rediyoaktif". Wannan binciken ya buɗe hanya don samar da isotopes na rediyoaktif na wucin gadi, waɗanda suka samo mahimman aikace-aikace masu mahimmanci da mahimmanci a cikin bincike na asali, magani, da masana'antu.
A ƙarshe, yana da kyau a ambaci masana kimiyyar lissafi daga Amurka. Ernest Lawrence tare da abokan aiki daga Berkeley da masu bincike daga Pasadena, daga cikinsu akwai wani dan sanda wanda ke kan aikin horon. Andrzej Soltan. An lura da ƙidayar bugun jini ta masu ƙididdigewa, kodayake na'ura mai sauri ya riga ya daina aiki. Ba su son wannan kirga. Koyaya, ba su fahimci cewa suna fuskantar wani muhimmin sabon al'amari ba kuma kawai sun rasa gano aikin rediyo na wucin gadi.
