{"id":18253,"date":"2020-06-27T15:28:48","date_gmt":"2020-06-27T15:28:48","guid":{"rendered":"https:\/\/www.radiation-dosimetry.org\/o-que-e-producao-de-par-de-positron-eletron-definicao\/"},"modified":"2020-07-24T10:36:42","modified_gmt":"2020-07-24T10:36:42","slug":"o-que-e-producao-de-par-de-positron-eletron-definicao","status":"publish","type":"post","link":"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-producao-de-par-de-positron-eletron-definicao\/","title":{"rendered":"O que \u00e9 produ\u00e7\u00e3o de par de p\u00f3sitron-el\u00e9tron – defini\u00e7\u00e3o"},"content":{"rendered":"
\n
A produ\u00e7\u00e3o de pares \u00e9 um fen\u00f4meno da natureza em que a energia \u00e9 diretamente convertida em mat\u00e9ria.\u00a0Em altas energias dos raios gama, a produ\u00e7\u00e3o de pares domina.\u00a0Dosimetria de Radia\u00e7\u00e3o<\/div>\n<\/div>\n
<\/div>\n
\n
\n
<\/div>\n

Produ\u00e7\u00e3o de Par Positron-El\u00e9tron<\/h2>\n<\/div>\n<\/div>\n
\n
\n

Em geral, a\u00a0produ\u00e7\u00e3o de pares<\/strong>\u00a0\u00e9 um fen\u00f4meno da natureza em que a\u00a0energia \u00e9 diretamente convertida em mat\u00e9ria<\/strong>\u00a0.\u00a0O fen\u00f4meno da produ\u00e7\u00e3o de pares pode ser visto de duas maneiras diferentes.\u00a0Uma maneira \u00e9 como\u00a0uma part\u00edcula e antipart\u00edcula<\/strong>\u00a0e a outra \u00e9 como\u00a0uma part\u00edcula e um buraco<\/strong>\u00a0.\u00a0A primeira maneira pode ser representada pela forma\u00e7\u00e3o de\u00a0el\u00e9trons e p\u00f3sitrons<\/strong>\u00a0, a partir de um pacote de energia eletromagn\u00e9tica (\u00a0f\u00f3ton de alta energia – raios gama<\/strong>\u00a0) viajando atrav\u00e9s da mat\u00e9ria.\u00a0\u00c9 uma das maneiras poss\u00edveis pelas quais os raios gama interagem com a mat\u00e9ria.\u00a0Em altas energias, essa intera\u00e7\u00e3o domina<\/strong>\u00a0.\u00a0Para que ocorra a produ\u00e7\u00e3o de pares el\u00e9tron-p\u00f3sitron, a energia eletromagn\u00e9tica do f\u00f3ton deve estar acimauma energia limiar<\/strong>\u00a0equivalente \u00e0 massa restante de dois el\u00e9trons.\u00a0A energia limiar (a massa total de repouso das part\u00edculas produzidas) para a produ\u00e7\u00e3o de pares el\u00e9tron-p\u00f3sitron \u00e9 igual a\u00a01,02MeV (2 x 0,511MeV)<\/strong>\u00a0porque a massa restante de um \u00fanico el\u00e9tron \u00e9 equivalente a 0,511MeV de energia.Se a energia do f\u00f3ton original \u00e9 maior que 1,02MeV, qualquer energia acima de 1,02MeV est\u00e1 de acordo com a lei de conserva\u00e7\u00e3o dividida entre a energia cin\u00e9tica do movimento das duas part\u00edculas. A presen\u00e7a de\u00a0um campo el\u00e9trico de um \u00e1tomo pesado<\/strong>\u00a0, como chumbo ou ur\u00e2nio,\u00a0\u00e9 essencial para satisfazer conserva\u00e7\u00e3o de momento e energia<\/strong>\u00a0.\u00a0Para satisfazer a conserva\u00e7\u00e3o do momento e da energia, o n\u00facleo at\u00f4mico deve receber algum momento.\u00a0Portanto, umfot\u00e3o<\/a>\u00a0produ\u00e7\u00e3o de pares\u00a0em espa\u00e7o livre n\u00e3o pode ocorrer<\/strong>\u00a0.Al\u00e9m disso, o positr\u00e3o \u00e9 o anti-part\u00edcula do electr\u00e3o, por isso, quando um positr\u00e3o vem a descansar, ele interage com um outro electr\u00e3o, resultando na aniquila\u00e7\u00e3o das duas part\u00edculas e a convers\u00e3o completa do seu repousar a massa de volta \u00e0 energia pura (de acordo com a\u00a0f\u00f3rmula\u00a0E = mc\u00a02<\/sup>\u00a0) na forma de dois raios gama de 0,511 MeV de dire\u00e7\u00e3o oposta (f\u00f3tons).\u00a0O fen\u00f4meno da produ\u00e7\u00e3o de pares est\u00e1, portanto, conectado \u00e0\u00a0cria\u00e7\u00e3o e destrui\u00e7\u00e3o da mat\u00e9ria<\/strong>\u00a0em uma \u00fanica rea\u00e7\u00e3o.<\/p>\n

<\/div>\n

Produ\u00e7\u00e3o de Par Positron-El\u00e9tron – Se\u00e7\u00e3o Transversal<\/h2>\n

A probabilidade de produ\u00e7\u00e3o de pares, caracterizada pela se\u00e7\u00e3o transversal, \u00e9 uma\u00a0fun\u00e7\u00e3o muito complicada baseada na mec\u00e2nica qu\u00e2ntica<\/strong>\u00a0.\u00a0Em geral, a se\u00e7\u00e3o transversal aumenta aproximadamente com o quadrado do n\u00famero at\u00f4mico\u00a0(\u03c3\u00a0p<\/sub>\u00a0~ Z\u00a02<\/sup>\u00a0)<\/strong>\u00a0e aumenta com a energia do f\u00f3ton, mas essa depend\u00eancia \u00e9 muito mais complexa.<\/p>\n<\/div>\n<\/div>\n

\n
\n

\"\"<\/a><\/p>\n

<\/div>\n

\"Produ\u00e7\u00e3o<\/a>Se\u00e7\u00e3o transversal da produ\u00e7\u00e3o de pares no campo nuclear e no campo de el\u00e9trons.<\/p>\n<\/div>\n<\/div>\n

\n
\n

<\/h2>\n<\/div>\n<\/div>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

 <\/p>\n

……………………………………………………………………………………………………………………………….<\/p>\n

Este artigo \u00e9 baseado na tradu\u00e7\u00e3o autom\u00e1tica do artigo original em ingl\u00eas. Para mais informa\u00e7\u00f5es, consulte o artigo em ingl\u00eas. Voc\u00ea pode nos ajudar. Se voc\u00ea deseja corrigir a tradu\u00e7\u00e3o, envie-a para: translations@nuclear-power.com ou preencha o formul\u00e1rio de tradu\u00e7\u00e3o on-line. Agradecemos sua ajuda, atualizaremos a tradu\u00e7\u00e3o o mais r\u00e1pido poss\u00edvel. Obrigado.<\/p>\n","protected":false},"excerpt":{"rendered":"

A produ\u00e7\u00e3o de pares \u00e9 um fen\u00f4meno da natureza em que a energia \u00e9 diretamente convertida em mat\u00e9ria.\u00a0Em altas energias dos raios gama, a produ\u00e7\u00e3o de pares domina.\u00a0Dosimetria de Radia\u00e7\u00e3o Produ\u00e7\u00e3o de Par Positron-El\u00e9tron Em geral, a\u00a0produ\u00e7\u00e3o de pares\u00a0\u00e9 um fen\u00f4meno da natureza em que a\u00a0energia \u00e9 diretamente convertida em mat\u00e9ria\u00a0.\u00a0O fen\u00f4meno da produ\u00e7\u00e3o de … Ler mais<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[51],"tags":[],"yoast_head":"\nO que \u00e9 produ\u00e7\u00e3o de par de p\u00f3sitron-el\u00e9tron - defini\u00e7\u00e3o<\/title>\n<meta name=\"description\" content=\"A produ\u00e7\u00e3o de pares \u00e9 um fen\u00f4meno da natureza em que a energia \u00e9 diretamente convertida em mat\u00e9ria. Em altas energias dos raios gama, a produ\u00e7\u00e3o de pares domina. Dosimetria de Radia\u00e7\u00e3o\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-producao-de-par-de-positron-eletron-definicao\/\" \/>\n<meta property=\"og:locale\" content=\"pt_BR\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"O que \u00e9 produ\u00e7\u00e3o de par de p\u00f3sitron-el\u00e9tron - defini\u00e7\u00e3o\" \/>\n<meta property=\"og:description\" content=\"A produ\u00e7\u00e3o de pares \u00e9 um fen\u00f4meno da natureza em que a energia \u00e9 diretamente convertida em mat\u00e9ria. Em altas energias dos raios gama, a produ\u00e7\u00e3o de pares domina. Dosimetria de Radia\u00e7\u00e3o\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-producao-de-par-de-positron-eletron-definicao\/\" \/>\n<meta property=\"og:site_name\" content=\"Radiation Dosimetry\" \/>\n<meta property=\"article:published_time\" content=\"2020-06-27T15:28:48+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2020-07-24T10:36:42+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.radiation-dosimetry.org\/wp-content\/uploads\/2019\/12\/Pair-production-in-chamber-216x300.jpg\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\">\n\t<meta name=\"twitter:data1\" content=\"Nick Connor\">\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\">\n\t<meta name=\"twitter:data2\" content=\"2 minutos\">\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.radiation-dosimetry.org\/#website\",\"url\":\"https:\/\/www.radiation-dosimetry.org\/\",\"name\":\"Radiation Dosimetry\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":\"https:\/\/www.radiation-dosimetry.org\/?s={search_term_string}\",\"query-input\":\"required name=search_term_string\"}],\"inLanguage\":\"pt-BR\"},{\"@type\":\"ImageObject\",\"@id\":\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-producao-de-par-de-positron-eletron-definicao\/#primaryimage\",\"inLanguage\":\"pt-BR\",\"url\":\"\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-producao-de-par-de-positron-eletron-definicao\/#webpage\",\"url\":\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-producao-de-par-de-positron-eletron-definicao\/\",\"name\":\"O que \\u00e9 produ\\u00e7\\u00e3o de par de p\\u00f3sitron-el\\u00e9tron - defini\\u00e7\\u00e3o\",\"isPartOf\":{\"@id\":\"https:\/\/www.radiation-dosimetry.org\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-producao-de-par-de-positron-eletron-definicao\/#primaryimage\"},\"datePublished\":\"2020-06-27T15:28:48+00:00\",\"dateModified\":\"2020-07-24T10:36:42+00:00\",\"author\":{\"@id\":\"https:\/\/www.radiation-dosimetry.org\/#\/schema\/person\/e8c544db9afedaec8574d6464f9398bb\"},\"description\":\"A produ\\u00e7\\u00e3o de pares \\u00e9 um fen\\u00f4meno da natureza em que a energia \\u00e9 diretamente convertida em mat\\u00e9ria. Em altas energias dos raios gama, a produ\\u00e7\\u00e3o de pares domina. Dosimetria de Radia\\u00e7\\u00e3o\",\"inLanguage\":\"pt-BR\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-producao-de-par-de-positron-eletron-definicao\/\"]}]},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.radiation-dosimetry.org\/#\/schema\/person\/e8c544db9afedaec8574d6464f9398bb\",\"name\":\"Nick Connor\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","_links":{"self":[{"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/posts\/18253"}],"collection":[{"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/comments?post=18253"}],"version-history":[{"count":0,"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/posts\/18253\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/media?parent=18253"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/categories?post=18253"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/tags?post=18253"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}