Pamaso pa zojambulajambula patatu, ndiye kuti, za kupezeka kwa radioactivity yokumba

Nthawi ndi nthawi m'mbiri ya fizikiki pali zaka "zodabwitsa" pamene kuyesetsa kwa ofufuza ambiri kumatsogolera kuzinthu zambiri zotulukira. Momwemonso zinaliri ndi 1820, chaka cha magetsi, 1905, chaka chozizwitsa cha mapepala anayi a Einstein, 1913, chaka chogwirizana ndi phunziro la mapangidwe a atomu, ndipo potsiriza 1932, pamene mndandanda wa zotulukira zamakono ndi kupita patsogolo kwa atomu. kukhazikitsidwa kwa nyukiliya physics.

ongokwatirana kumene

Irina, mwana wamkazi wamkulu wa Marie Skłodowska-Curie ndi Pierre Curie, anabadwira ku Paris mu 1897 (1). Mpaka zaka khumi ndi ziwiri, iye anakulira kunyumba, mu "sukulu" yaing'ono yopangidwa ndi asayansi otchuka kwa ana ake, amene anali pafupifupi khumi ophunzira. Aphunzitsiwo anali: Marie Sklodowska-Curie (physics), Paul Langevin (masamu), Jean Perrin (chemistry), ndi zaumunthu zinaphunzitsidwa makamaka ndi amayi a ophunzira. Nthawi zambiri maphunziro ankachitikira m’nyumba za aphunzitsi, pamene ana ankaphunzira physics ndi chemistry m’ma laboratories enieni.

Chifukwa chake, chiphunzitso cha physics ndi chemistry chinali kupeza chidziwitso kudzera muzochita zenizeni. Kuyesera kulikonse kopambana kunakondweretsa ofufuza achichepere. Izi zinali zoyeserera zenizeni zomwe zinayenera kumvetsetsedwa ndi kuchitidwa mosamala, ndipo ana omwe anali mu labotale ya Marie Curie anayenera kukhala mu dongosolo lachitsanzo. Chidziwitso chanthanthi chinayeneranso kupezedwa. Njirayi, monga tsogolo la ophunzira a sukuluyi, pambuyo pake asayansi abwino komanso odziwika bwino, inakhala yothandiza.

2. Frederic Joliot (Chithunzi ndi Harcourt)

Komanso, agogo a abambo a Irena, dokotala, ankathera nthawi yochuluka kwa mdzukulu wamasiye wa abambo ake, kusangalala ndi kuwonjezera maphunziro ake a sayansi ya chilengedwe. Mu 1914, Irene anamaliza maphunziro a upainiya a Collège Sévigé ndipo analowa luso la masamu ndi sayansi ku Sorbonne. Izi zinachitika pamene nkhondo yoyamba yapadziko lonse inayamba. Mu 1916 adagwirizana ndi amayi ake ndipo pamodzi adakonza chithandizo cha radiological mu French Red Cross. Nkhondo itatha, analandira digiri ya bachelor. Mu 1921, ntchito yake yoyamba ya sayansi inasindikizidwa. Iye anali odzipereka kwa mtima wa atomiki misa klorini ku mchere zosiyanasiyana. Muzowonjezera zake, adagwira ntchito limodzi ndi amayi ake, polimbana ndi ma radioactivity. M'mawu ake a udokotala, omwe adatetezedwa mu 1925, adaphunzira tinthu tating'onoting'ono ta polonium.

Frederic Joliot anabadwa mu 1900 ku Paris (2). Kuyambira ali ndi zaka eyiti amaphunzira kusukulu ku So, amakhala kusukulu yogonera. Panthawiyo, ankakonda masewera kuposa maphunziro, makamaka mpira. Kenako anasinthana kukaphunzira kusukulu za sekondale ziwiri. Monga Irene Curie, bambo ake anamwalira msanga. Mu 1919 anapambana mayeso pa École de Physique et de Chemie Industrielle de la Ville de Paris (School of Industrial Physics and Industrial Chemistry ya mzinda wa Paris). Anamaliza maphunziro ake mu 1923. Pulofesa wake, Paul Langevin, adaphunzira za luso la Frederick ndi makhalidwe ake. Pambuyo pa miyezi 15 ya usilikali, molamulidwa ndi Langevin, adasankhidwa kukhala wothandizira labotale ya Marie Skłodowska-Curie ku Radium Institute ndi thandizo lochokera ku Rockefeller Foundation. Kumeneko anakumana ndi Irene Curie, ndipo mu 1926 achinyamatawo anakwatirana.

Frederick anamaliza maphunziro ake a udokotala pa electrochemistry of radioactive elements mu 1930. Kale m'mbuyomo, anali ataika kale zofuna zake pa kafukufuku wa mkazi wake, ndipo atatha kuteteza zolemba za Frederick za udokotala, adagwira ntchito limodzi. Chimodzi mwazofunikira zawo zoyambirira chinali kukonzekera polonium, yomwe ndi gwero lamphamvu la alpha particles, i.e. maziko a helium.(₂⁴Iye). Anayamba kuchokera paudindo wosatsutsika, chifukwa anali Marie Curie yemwe adapatsa mwana wake gawo lalikulu la polonium. Lew Kowarsky, wothandizana nawo pambuyo pake, adawafotokozera motere: Irena anali "katswiri wabwino kwambiri", "anagwira ntchito mokongola kwambiri komanso mosamala", "anamvetsetsa kwambiri zomwe anali kuchita." Mwamuna wake anali ndi "malingaliro owoneka bwino, okulirapo." "Iwo ankathandizana bwino lomwe ndipo ankadziwa." Kuchokera pamalingaliro a mbiriyakale ya sayansi, chidwi kwambiri kwa iwo chinali zaka ziwiri: 1932-34.

Iwo pafupifupi anapeza neutroni

"Pafupifupi" ndizofunikira kwambiri. Posakhalitsa anaphunzira za choonadi chomvetsa chisoni chimenechi. Mu 1930 ku Berlin, Ajeremani awiri - Walter Bothe i Hubert Becker - Kufufuza momwe ma atomu opepuka amachitira akaphulitsidwa ndi tinthu ta alpha. Beryllium Shield (₄⁹Be) ikaphulitsidwa ndi tinthu tating'ono ta alpha timatulutsa cheza cholowera kwambiri komanso champhamvu kwambiri. Malinga ndi oyesererawo, ma radiation amenewa ayenera kuti anali ma radiation amphamvu a electromagnetic.

Pa nthawiyi, Irena ndi Frederick anathana ndi vutolo. Magwero awo a tinthu tating'onoting'ono ta alpha anali amphamvu kwambiri kuposa kale lonse. Anagwiritsa ntchito chipinda chamtambo kuti awone zomwe zikuchitika. Kumapeto kwa January 1932, iwo analengeza poyera kuti inali kuwala kwa gamma komwe kunatulutsa ma protoni amphamvu kwambiri ku chinthu chokhala ndi haidrojeni. Sanamvetsetse zimene zinali m’manja mwao ndi zimene zinali kucitika.. Pambuyo powerenga James Chadwick (3) ku Cambridge nthawi yomweyo anayamba kugwira ntchito, kuganiza kuti sikunali kutentha kwa gamma, koma ma neutroni ananeneratu ndi Rutherford zaka zingapo pasadakhale. Atayesa kangapo, adatsimikiza za kuwona kwa neutroni ndipo adapeza kuti kulemera kwake kuli kofanana ndi pulotoni. Pa February 17, 1932, iye anapereka kalata ku magazini ya Nature yotchedwa "The Possible Existence of the Neutron."

Inalidi nyutroni, ngakhale kuti Chadwick ankakhulupirira kuti nyutroni imapangidwa ndi pulotoni ndi electron. Pokhapokha mu 1934 adamvetsetsa ndikutsimikizira kuti nyutroni ndi gawo loyambira. Chadwick adalandira Mphotho ya Nobel mu Fizikisi mu 1935. Ngakhale adazindikira kuti adaphonya chinthu chofunikira, a Joliot-Curies adapitiliza kafukufuku wawo m'derali. Iwo anazindikira kuti kachitidwe kameneka kanatulutsa kuwala kwa gamma kuwonjezera pa manyutroni, kotero iwo analemba za nyukiliya:

, kumene Ef ndi mphamvu ya gamma-quantum. Zoyeserera zofananira zidachitika ndi ₉¹⁹F.

Anaphonyanso kutsegula

Miyezi ingapo asanatulukire positron, Joliot-Curie anali ndi zithunzi za, mwa zina, njira yokhotakhota, ngati kuti ndi electron, koma yokhotakhota mosiyana ndi electron. Zithunzizo zinajambulidwa m’chipinda cha chifunga chomwe chili m’dera la maginito. Kutengera izi, banjali lidalankhula za ma electron omwe amapita mbali ziwiri, kuchokera kugwero ndi komwe kumachokera. M'malo mwake, omwe amalumikizidwa ndi chitsogozo "ku gwero" anali ma positrons, kapena ma elekitironi abwino omwe amasuntha kutali ndi gwero.

Panthawiyi, ku United States chakumapeto kwa chilimwe cha 1932. Carl David Anderson (4), mwana wa anthu osamukira ku Sweden, anaphunzira kuwala kwa chilengedwe m’chipinda chamtambo mothandizidwa ndi mphamvu ya maginito. Kuwala kwa cosmic kumabwera kudziko lapansi kuchokera kunja. Anderson, kuti atsimikize za mayendedwe ndi kayendedwe ka tinthu tating'onoting'ono, mkati mwa chipindacho adadutsa tinthu tating'onoting'ono kudzera mu mbale yachitsulo, komwe adataya mphamvu zina. Pa Ogasiti 2, adawona njira, yomwe mosakayikira adatanthauzira ngati electron yabwino.

Ndizofunikira kudziwa kuti Dirac adaneneratu kale za kukhalapo kwachinthu chotere. Komabe, Anderson sanatsatire mfundo zongopeka m’maphunziro ake a kuwala kwa zakuthambo. M'nkhaniyi, adatcha zomwe adapezazo mwangozi.

Apanso, Joliot-Curie adayenera kupirira ntchito yosatsutsika, koma adachita kafukufuku wowonjezereka m'derali. Iwo anapeza kuti ma photon a gamma-ray amatha kuzimiririka pafupi ndi phata lolemera, kupanga awiri a electron-positron, mwachiwonekere motsatira njira yotchuka ya Einstein E = mc2 ndi lamulo la kusunga mphamvu ndi mphamvu. Pambuyo pake, Frederick mwiniwakeyo adatsimikizira kuti pali njira yosowa ma electron-positron awiri, zomwe zimapangitsa kuti ma gamma quanta apangidwe. Kuphatikiza pa ma positrons ochokera ku ma electron-positron pairs, anali ndi ma positrons ochokera kunyukiliya.

5. Msonkhano wa Seventh Solvay, 1933

Atakhala kutsogolo: Irene Joliot-Curie (wachiwiri kuchokera kumanzere),

Maria Skłodowska-Curie (wachisanu kuchokera kumanzere), Lise Meitner (wachiwiri kuchokera kumanja).

radioactivity yopanga

Kupezeka kwa radioactivity yochita kupanga sikunali kochitika nthawi yomweyo. Mu February 1933, powombera aluminium, fluorine, ndiyeno sodium ndi alpha particles, Joliot anapeza ma neutroni ndi isotopu zosadziwika. Mu July 1933, adalengeza kuti, poyatsa aluminiyamu ndi tinthu tating'onoting'ono ta alpha, samawona ma neutroni okha, komanso positrons. Malingana ndi Irene ndi Frederick, ma positrons muzochitika za nyukiliya sizikanatheka chifukwa cha mapangidwe a electron-positron pairs, koma amayenera kubwera kuchokera ku nucleus ya atomiki.

Msonkhano Wachisanu ndi chiwiri wa Solvay (5) unachitika ku Brussels pa October 22-29, 1933. Iwo ankatchedwa "The Structure and Properties of Atomic Nuclei". Kunafika akatswiri a sayansi ya zakuthambo okwana 41, kuphatikizapo akatswiri odziwika kwambiri padziko lonse lapansi. Joliot adanenanso zotsatira za kuyesa kwawo, ponena kuti boron ndi aluminiyamu yoyatsa ndi kuwala kwa alpha imapanga nyutroni yokhala ndi positron kapena proton.. Pamsonkhanowu Lisa Meitner Iye adanena kuti muzoyesera zomwezo ndi aluminiyamu ndi fluorine, sanapeze zotsatira zomwezo. Potanthauzira, iye sanagwirizane ndi maganizo a banja la Paris za nyukiliya ya chiyambi cha positrons. Komabe, atabwerera kuntchito ku Berlin, adachitanso zoyeserazi ndipo pa November 18, m'kalata yopita kwa Joliot-Curie, adavomereza kuti tsopano, m'malingaliro ake, positrons imawonekeradi kuchokera pamphuno.

Kuphatikiza apo, msonkhano uno Francis Perrin, mnzawo ndi bwenzi lapamtima la ku Paris, analankhulapo pa nkhani ya positrons. Zinadziwika kuchokera pazoyeserera kuti adapeza kuchuluka kwa ma positron, ofanana ndi kuchuluka kwa tinthu tating'onoting'ono ta beta pakuwola kwachilengedwe. Kusanthula kwina kwa mphamvu za ma positroni ndi ma neutroni Perrin adapeza kuti zotulutsa ziwiri ziyenera kusiyanitsidwa pano: choyamba, kutulutsa kwa ma neutroni, limodzi ndi kupangidwa kwa phata losakhazikika, ndiyeno kutulutsa kwa positroni kuchokera pakatikati.

Pambuyo pa msonkhano Joliot adayimitsa mayeserowa kwa miyezi iwiri. Ndiyeno, mu December 1933, Perrin analemba maganizo ake pa nkhaniyi. Pa nthawi yomweyo, komanso mu December Enrico Fermi adapereka chiphunzitso cha kuwonongeka kwa beta. Izi zidakhala ngati maziko ongoyerekeza kutanthauzira zochitika. Kumayambiriro kwa 1934, banjali lochokera ku likulu la France linayambiranso kuyesa kwawo.

Ndendende pa Januware 11, Lachinayi masana, Frédéric Joliot anatenga zojambulazo za aluminiyamu ndikuziphulitsa ndi tinthu tating'ono ta alpha kwa mphindi 10. Kwa nthawi yoyamba, adagwiritsa ntchito kauntala ya Geiger-Muller kuti azindikire, osati chipinda cha chifunga, monga kale. Anawona modabwa kuti pamene adachotsa gwero la alpha particles kuchokera ku zojambulazo, kuwerengera kwa positrons sikunayime, ma counters anapitiriza kuwawonetsa, chiwerengero chawo chokha chinachepa kwambiri. Anatsimikiza kuti theka la moyo likhale mphindi 3 ndi masekondi 15. Kenako anachepetsa mphamvu ya tinthu tating’ono ta alpha togwera pachojambulacho poika chiboliboli cha mtovu panjira. Ndipo iwo anali ndi positrons ochepa, koma theka la moyo silinasinthe.

Kenako adayesanso kuyesa komweko kwa boron ndi magnesium, ndipo adapeza theka la moyo pazoyeserera izi za mphindi 14 ndi mphindi 2,5, motsatana. Kenako, mayesero amenewa inachitika ndi haidrojeni, lifiyamu, carbon, beryllium, nayitrogeni, mpweya, fluorine, sodium, calcium, faifi tambala ndi siliva - koma sanaone chodabwitsa chofanana ndi aluminium, boron ndi magnesium. Chophimba cha Geiger-Muller sichimasiyanitsa pakati pa tinthu tating'onoting'ono tating'ono tating'ono tating'ono, choncho Frédéric Joliot adatsimikiziranso kuti imagwira ntchito ndi ma electron abwino. Mbali yaukadaulo inalinso yofunika pakuyesaku, mwachitsanzo, kukhalapo kwa gwero lamphamvu la tinthu tating'onoting'ono ta alpha komanso kugwiritsa ntchito kauntala ya tinthu tating'onoting'ono, monga Geiger-Muller counter.

Monga tafotokozera kale ndi gulu la Joliot-Curie, ma positroni ndi ma neutroni amatulutsidwa nthawi imodzi mukusintha kwanyukiliya komwe kumawonedwa. Tsopano, kutsatira malingaliro a Francis Perrin ndi kuŵerenga maganizo a Fermi, banjalo linafika ponena kuti mphamvu ya nyukiliya yoyamba inapanga nyukiliyasi yosakhazikika ndi nyutroni, kutsatiridwa ndi beta kuphatikizapo kuwola kwa phata losakhazikika limenelo. Kotero iwo akhoza kulemba zotsatirazi:

A Joliots adawona kuti ma isotopu omwe adayambitsa ma radioactive anali ndi moyo waufupi kwambiri kuti usakhalepo mwachilengedwe. Iwo adalengeza zotsatira zawo pa January 15, 1934, m'nkhani yakuti "A New Type of Radioactivity". Kumayambiriro kwa February, adakwanitsa kuzindikira phosphorous ndi nayitrogeni kuchokera kuzinthu ziwiri zoyambirira zomwe zidasonkhanitsidwa pang'ono. Posakhalitsa panali ulosi woti ma isotopu owonjezera a radioactive atha kupangidwa muzochita za bombardment ya nyukiliya, komanso mothandizidwa ndi ma protoni, ma deuteron ndi ma neutroni. M'mwezi wa Marichi, Enrico Fermi adabetcherana kuti izi zichitika posachedwa pogwiritsa ntchito ma neutroni. Posakhalitsa adapambana yekha kubetcha.

Irena ndi Frederick adalandira Mphotho ya Nobel mu Chemistry mu 1935 chifukwa cha "kaphatikizidwe kazinthu zatsopano za radioactive". Kutulukira kumeneku kunatsegula njira yopangira ma isotopu a radioactive, omwe apeza ntchito zambiri zofunika komanso zofunika kwambiri pakufufuza, zamankhwala, ndi mafakitale.

Pomaliza, ndikofunikira kutchula akatswiri asayansi aku USA, Ernest Lawrence ndi anzawo aku Berkeley ndi ofufuza ochokera ku Pasadena, omwe mwa iwo anali Pole yemwe anali pa internship. Andrzej Soltan. Kuwerengera kwa ma pulse ndi ma counters kunawonedwa, ngakhale accelerator inali itasiya kale kugwira ntchito. Sanakonde kuwerengera uku. Komabe, sanazindikire kuti akukumana ndi chinthu chatsopano chofunikira komanso kuti amangosowa kupezeka kwa radioactivity yochita kupanga ...