{"id":17609,"date":"2020-06-16T01:42:10","date_gmt":"2020-06-16T01:42:10","guid":{"rendered":"https:\/\/www.radiation-dosimetry.org\/o-que-e-excitacao-por-radiacao-ionizante-definicao\/"},"modified":"2020-07-21T12:20:32","modified_gmt":"2020-07-21T12:20:32","slug":"o-que-e-excitacao-por-radiacao-ionizante-definicao","status":"publish","type":"post","link":"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-excitacao-por-radiacao-ionizante-definicao\/","title":{"rendered":"O que \u00e9 excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante &#8211; Defini\u00e7\u00e3o"},"content":{"rendered":"<div class=\"su-quote su-quote-style-default\">\n<div class=\"su-quote-inner su-u-clearfix su-u-trim\">Os el\u00e9trons podem alcan\u00e7ar a banda de condu\u00e7\u00e3o quando s\u00e3o excitados por radia\u00e7\u00e3o ionizante (ou seja, devem obter energia maior que o Egap).\u00a0Excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante<\/div>\n<\/div>\n<div class=\"su-divider su-divider-style-dotted\"><\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<p><a href=\"https:\/\/www.radiation-dosimetry.org\/wp-content\/uploads\/2019\/12\/Valence-Band-Conduction-Band-Band-Gap.png\"><img loading=\"lazy\" class=\"alignright wp-image-26111 lazy-loaded\" src=\"https:\/\/www.radiation-dosimetry.org\/wp-content\/uploads\/2019\/12\/Valence-Band-Conduction-Band-Band-Gap.png\" alt=\"Faixa de Valence - Banda de Condu\u00e7\u00e3o - Lacuna da Banda\" width=\"477\" height=\"329\" data-lazy-type=\"image\" data-src=\"https:\/\/www.radiation-dosimetry.org\/wp-content\/uploads\/2019\/12\/Valence-Band-Conduction-Band-Band-Gap.png\" \/><\/a>Em geral, os\u00a0<strong>semicondutores<\/strong>\u00a0s\u00e3o materiais, inorg\u00e2nicos ou org\u00e2nicos, que t\u00eam a capacidade de controlar sua condu\u00e7\u00e3o, dependendo da estrutura qu\u00edmica, temperatura, ilumina\u00e7\u00e3o e presen\u00e7a de dopantes.\u00a0O nome\u00a0<strong>semicondutor<\/strong>\u00a0vem do fato de que esses materiais t\u00eam uma\u00a0<strong>condutividade el\u00e9trica<\/strong>\u00a0entre a de um metal, como cobre, ouro, etc. e um isolador, como o vidro.\u00a0Eles t\u00eam um\u00a0<strong>gap de energia<\/strong>\u00a0menor que 4eV (cerca de 1eV).\u00a0Na f\u00edsica do estado s\u00f3lido, esse gap de energia ou gap de banda \u00e9 um intervalo de energia entre a banda de val\u00eancia e a banda de condu\u00e7\u00e3o, onde os estados de el\u00e9trons s\u00e3o proibidos.\u00a0Ao contr\u00e1rio dos condutores, os el\u00e9trons em um semicondutor devem obter energia (por exemplo, a partir de radia\u00e7\u00e3o ionizante) para atravessar a folga da banda e alcan\u00e7ar a banda de condu\u00e7\u00e3o.<\/p>\n<h2>Excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante<\/h2>\n<p><strong>A energia para a excita\u00e7\u00e3o<\/strong>\u00a0pode ser obtida de diferentes maneiras.\u00a0Os el\u00e9trons podem alcan\u00e7ar a banda de condu\u00e7\u00e3o quando s\u00e3o\u00a0<strong>excitados por radia\u00e7\u00e3o ionizante<\/strong>\u00a0(ou seja, devem obter energia maior que o Egap).\u00a0Em geral,\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/interaction-radiation-matter\/interaction-heavy-charged-particles\/\">part\u00edculas carregadas pesadas<\/a>\u00a0transferem energia principalmente por:<\/p>\n<ul>\n<li><strong>Excita\u00e7\u00e3o.\u00a0<\/strong>A part\u00edcula carregada pode transferir energia para o \u00e1tomo, elevando os el\u00e9trons para n\u00edveis mais altos de energia.<\/li>\n<li><strong>Ionizacao.\u00a0<\/strong>A ioniza\u00e7\u00e3o pode ocorrer quando a part\u00edcula carregada possui energia suficiente para remover um el\u00e9tron.\u00a0Isso resulta na cria\u00e7\u00e3o de pares de \u00edons na mat\u00e9ria circundante.<\/li>\n<\/ul>\n<p>Uma vari\u00e1vel conveniente que descreve as propriedades de ioniza\u00e7\u00e3o do meio circundante \u00e9\u00a0<strong>o poder de parada<\/strong>\u00a0.\u00a0A express\u00e3o cl\u00e1ssica que descreve a perda de energia espec\u00edfica \u00e9 conhecida como\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/interaction-radiation-matter\/interaction-heavy-charged-particles\/stopping-power-bethe-formula\/\">f\u00f3rmula de Bethe<\/a>\u00a0.\u00a0Para\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/atomic-nuclear-physics\/fundamental-particles\/alpha-particle\/\">part\u00edculas alfa<\/a>\u00a0e\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/atomic-nuclear-physics\/fundamental-particles\/alpha-particle\/\">part\u00edculas<\/a>\u00a0mais pesadas,\u00a0<strong>o poder<\/strong>\u00a0de\u00a0<strong>parada<\/strong>\u00a0da maioria dos materiais \u00e9 muito alto para part\u00edculas carregadas pesadas e essas part\u00edculas t\u00eam faixas muito curtas.<\/p>\n<p>Al\u00e9m dessas intera\u00e7\u00f5es, as\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/atomic-nuclear-physics\/fundamental-particles\/beta-particle\/\">part\u00edculas beta<\/a>\u00a0tamb\u00e9m perdem energia pelo processo radiativo conhecido como\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/atomic-nuclear-physics\/fundamental-particles\/beta-particle\/bremsstrahlung-2\/\"><strong>bremsstrahlung<\/strong><\/a>\u00a0.\u00a0Da teoria cl\u00e1ssica, quando uma part\u00edcula carregada \u00e9 acelerada ou desacelerada,\u00a0<strong>ela deve irradiar energia<\/strong>\u00a0e a radia\u00e7\u00e3o de desacelera\u00e7\u00e3o \u00e9 conhecida como\u00a0<strong>bremsstrahlung (&#8220;radia\u00e7\u00e3o de frenagem&#8221;)<\/strong>\u00a0.<\/p>\n<p>Os f\u00f3tons (raios gama e raios X) podem ionizar \u00e1tomos diretamente (apesar de serem eletricamente neutros) atrav\u00e9s do efeito Fotoel\u00e9trico e do efeito Compton, mas a ioniza\u00e7\u00e3o secund\u00e1ria (indireta) \u00e9 muito mais significativa.\u00a0Embora seja conhecido um grande n\u00famero de poss\u00edveis intera\u00e7\u00f5es, existem tr\u00eas mecanismos principais de intera\u00e7\u00e3o com a mat\u00e9ria.<\/p>\n<ul>\n<li><strong><a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/interaction-radiation-matter\/interaction-gamma-radiation-matter\/photoelectric-effect\/\">Efeito fotoel\u00e9trico<\/a><\/strong><\/li>\n<li><strong><a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/interaction-radiation-matter\/interaction-gamma-radiation-matter\/compton-scattering\/\">Efeito Compton<\/a><\/strong><\/li>\n<li><strong><a href=\"https:\/\/www.nuclear-power.com\/nuclear-power\/reactor-physics\/interaction-radiation-matter\/interaction-gamma-radiation-matter\/pair-production\/\">Produ\u00e7\u00e3o em pares<\/a><\/strong><\/li>\n<\/ul>\n<p>Em todos os casos, uma part\u00edcula de radia\u00e7\u00e3o ionizante deposita uma parte de sua energia ao longo de seu caminho.\u00a0As part\u00edculas que passam pelo detector ionizam os \u00e1tomos do semicondutor, produzindo os\u00a0<strong>pares el\u00e9tron-buraco<\/strong>\u00a0.\u00a0Por exemplo, a espessura t\u00edpica do\u00a0<strong>detector<\/strong>\u00a0de\u00a0<strong>sil\u00edcio<\/strong>\u00a0\u00e9 de cerca de 300 \u00b5m, de modo que o n\u00famero de pares de el\u00e9trons-buraco gerados pela part\u00edcula ionizante m\u00ednima (MIP) que passa perpendicularmente ao detector \u00e9 de cerca de\u00a0<strong>3,2 x 10\u00a0<sup>4<\/sup><\/strong>\u00a0.\u00a0Este valor \u00e9 menor em compara\u00e7\u00e3o com o n\u00famero total de portadores livres no semicondutor intr\u00ednseco de uma superf\u00edcie de 1 cm\u00a0<sup>2<\/sup>\u00a0e a mesma espessura.\u00a0Observe que uma amostra de germ\u00e2nio puro a 20 \u00b0 C cont\u00e9m cerca de 1,26 \u00d7 10\u00a0<sup>21<\/sup>\u00a0\u00e1tomos, mas tamb\u00e9m cont\u00e9m 7,5 x 10\u00a0<sup>11<\/sup>el\u00e9trons livres e 7,5 x 10\u00a0<sup>11<\/sup>\u00a0buracos gerados constantemente a partir\u00a0<a href=\"https:\/\/www.nuclear-power.com\/nuclear-engineering\/thermodynamics\/what-is-energy-physics\/internal-energy-thermal-energy\/\">de energia t\u00e9rmica<\/a>\u00a0.\u00a0Como pode ser visto, a rela\u00e7\u00e3o sinal \/ ru\u00eddo (S \/ N) seria m\u00ednima.\u00a0A adi\u00e7\u00e3o de 0,001% de ars\u00e9nio (uma impureza) doa um extra de 10\u00a0<sup>15<\/sup>\u00a0electr\u00f5es livres no mesmo volume e a condutividade el\u00e9ctrica \u00e9 aumentada por um factor de 10.000.\u00a0No material dopado, a rela\u00e7\u00e3o sinal \/ ru\u00eddo (S \/ N) seria ainda menor.\u00a0<strong>O resfriamento do semicondutor<\/strong>\u00a0\u00e9 uma maneira de diminuir essa propor\u00e7\u00e3o.<\/p>\n<p>A melhoria pode ser alcan\u00e7ada com o uso de uma tens\u00e3o de polariza\u00e7\u00e3o reversa na jun\u00e7\u00e3o PN para esgotar o detector de portadores livres, que \u00e9 o princ\u00edpio dos detectores de radia\u00e7\u00e3o com mais sil\u00edcio.\u00a0Nesse caso, a tens\u00e3o negativa \u00e9 aplicada no lado p e positiva no segundo.\u00a0Os furos na regi\u00e3o p s\u00e3o atra\u00eddos da jun\u00e7\u00e3o em dire\u00e7\u00e3o ao contato p e da mesma forma para os el\u00e9trons e o contato n.<\/p>\n<\/div>\n<\/div>\n<div class=\"lgc-column lgc-grid-parent lgc-grid-100 lgc-tablet-grid-100 lgc-mobile-grid-100 lgc-equal-heights lgc-first lgc-last\">\n<div class=\"inside-grid-column\">\n<div class=\"su-spoiler su-spoiler-style-default su-spoiler-icon-arrow\" data-anchor=\"References\">\n<div class=\"su-spoiler-title\" tabindex=\"0\" role=\"button\"><\/div>\n<\/div>\n<\/div>\n<div tabindex=\"0\" role=\"button\">\n<p>&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;&#8230;.<\/p>\n<p>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<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Os el\u00e9trons podem alcan\u00e7ar a banda de condu\u00e7\u00e3o quando s\u00e3o excitados por radia\u00e7\u00e3o ionizante (ou seja, devem obter energia maior que o Egap).\u00a0Excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante Em geral, os\u00a0semicondutores\u00a0s\u00e3o materiais, inorg\u00e2nicos ou org\u00e2nicos, que t\u00eam a capacidade de controlar sua condu\u00e7\u00e3o, dependendo da estrutura qu\u00edmica, temperatura, ilumina\u00e7\u00e3o e presen\u00e7a de dopantes.\u00a0O nome\u00a0semicondutor\u00a0vem do fato de &#8230; <a title=\"O que \u00e9 excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante &#8211; Defini\u00e7\u00e3o\" class=\"read-more\" href=\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-excitacao-por-radiacao-ionizante-definicao\/\" aria-label=\"More on O que \u00e9 excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante &#8211; Defini\u00e7\u00e3o\">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":"<!-- This site is optimized with the Yoast SEO plugin v15.4 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>O que \u00e9 excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante - Defini\u00e7\u00e3o<\/title>\n<meta name=\"description\" content=\"Os el\u00e9trons podem atingir a banda de condu\u00e7\u00e3o quando s\u00e3o excitados por radia\u00e7\u00e3o ionizante (ou seja, devem obter energia maior que o Egap). Excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante\" \/>\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-excitacao-por-radiacao-ionizante-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 excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante - Defini\u00e7\u00e3o\" \/>\n<meta property=\"og:description\" content=\"Os el\u00e9trons podem atingir a banda de condu\u00e7\u00e3o quando s\u00e3o excitados por radia\u00e7\u00e3o ionizante (ou seja, devem obter energia maior que o Egap). Excita\u00e7\u00e3o por radia\u00e7\u00e3o ionizante\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-excitacao-por-radiacao-ionizante-definicao\/\" \/>\n<meta property=\"og:site_name\" content=\"Radiation Dosimetry\" \/>\n<meta property=\"article:published_time\" content=\"2020-06-16T01:42:10+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2020-07-21T12:20:32+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.radiation-dosimetry.org\/wp-content\/uploads\/2019\/12\/Valence-Band-Conduction-Band-Band-Gap.png\" \/>\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=\"3 minutos\">\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebSite\",\"@id\":\"https:\/\/www.radiation-dosimetry.org\/es\/#website\",\"url\":\"https:\/\/www.radiation-dosimetry.org\/es\/\",\"name\":\"Radiation Dosimetry\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":\"https:\/\/www.radiation-dosimetry.org\/es\/?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-excitacao-por-radiacao-ionizante-definicao\/#primaryimage\",\"inLanguage\":\"pt-BR\",\"url\":\"https:\/\/www.radiation-dosimetry.org\/wp-content\/uploads\/2019\/12\/Valence-Band-Conduction-Band-Band-Gap.png\"},{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-excitacao-por-radiacao-ionizante-definicao\/#webpage\",\"url\":\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-excitacao-por-radiacao-ionizante-definicao\/\",\"name\":\"O que \\u00e9 excita\\u00e7\\u00e3o por radia\\u00e7\\u00e3o ionizante - Defini\\u00e7\\u00e3o\",\"isPartOf\":{\"@id\":\"https:\/\/www.radiation-dosimetry.org\/es\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-excitacao-por-radiacao-ionizante-definicao\/#primaryimage\"},\"datePublished\":\"2020-06-16T01:42:10+00:00\",\"dateModified\":\"2020-07-21T12:20:32+00:00\",\"author\":{\"@id\":\"https:\/\/www.radiation-dosimetry.org\/es\/#\/schema\/person\/e8c544db9afedaec8574d6464f9398bb\"},\"description\":\"Os el\\u00e9trons podem atingir a banda de condu\\u00e7\\u00e3o quando s\\u00e3o excitados por radia\\u00e7\\u00e3o ionizante (ou seja, devem obter energia maior que o Egap). Excita\\u00e7\\u00e3o por radia\\u00e7\\u00e3o ionizante\",\"inLanguage\":\"pt-BR\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\/\/www.radiation-dosimetry.org\/pt-br\/o-que-e-excitacao-por-radiacao-ionizante-definicao\/\"]}]},{\"@type\":\"Person\",\"@id\":\"https:\/\/www.radiation-dosimetry.org\/es\/#\/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\/17609"}],"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=17609"}],"version-history":[{"count":0,"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/posts\/17609\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/media?parent=17609"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/categories?post=17609"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.radiation-dosimetry.org\/pt-br\/wp-json\/wp\/v2\/tags?post=17609"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}