{"id":262,"date":"2026-03-24T14:32:15","date_gmt":"2026-03-24T13:32:15","guid":{"rendered":"https:\/\/www.icone-neutron.fr\/moderer-un-neutron-libre\/"},"modified":"2026-07-21T16:24:45","modified_gmt":"2026-07-21T14:24:45","slug":"moderer-un-neutron-libre","status":"publish","type":"page","link":"https:\/\/www.icone-neutron.fr\/fr\/moderer-un-neutron-libre\/","title":{"rendered":"moderer-un-neutron-libre"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"262\" class=\"elementor elementor-262\">\n\t\t\t\t<div class=\"elementor-element elementor-element-4165832b e-flex e-con-boxed e-con e-parent\" data-id=\"4165832b\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-569fe24e elementor-widget elementor-widget-text-editor\" data-id=\"569fe24e\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<style>\n\/* =========================\n   BLOC PRINCIPAL BLANC\n========================= *\/\n.neutron-container{\n  max-width:1000px;\n  margin:60px auto;\n  padding:60px;\n  background:#ffffff;\n  border-radius:20px;\n  box-shadow:0 12px 35px rgba(0,0,0,0.12);\n  font-family:'Inter',Arial,sans-serif;\n  line-height:1.8;\n  color:#2f2f2f;\n}\n\n\/* =========================\n   TITRE\n========================= *\/\n.neutron-title{\n  font-size:42px;\n  font-weight:900;\n  color:#0d5cab;\n  padding-left:18px;\n  margin-bottom:50px;\n  position:relative;\n}\n\n.neutron-title::before{\n  content:\"\";\n  position:absolute;\n  left:0;\n  top:8px;\n  width:6px;\n  height:80%;\n  background:linear-gradient(180deg,#0d5cab,#3a8dde);\n  border-radius:3px;\n}\n\n\/* =========================\n   SOUS-TITRE\n========================= *\/\n.neutron-subtitle{\n  font-size:24px;\n  font-weight:700;\n  color:#0d5cab;\n  margin-top:50px;\n  margin-bottom:20px;\n}\n\n\/* =========================\n   TEXTE\n========================= *\/\n.neutron-container p{\n  margin-bottom:22px;\n  font-size:18px;\n  color:#444;\n}\n\n\/* =========================\n   FORMULE\n========================= *\/\n.neutron-formula{\n  background:#f4f7fb;\n  border-left:4px solid #0d5cab;\n  padding:18px;\n  font-family:\"Courier New\", monospace;\n  margin:25px 0;\n  border-radius:10px;\n  color:#163b68;\n}\n\n\/* =========================\n   IMAGE\n========================= *\/\n.neutron-image{\n  margin:30px 0;\n  text-align:center;\n}\n\n.neutron-image img{\n  max-width:100%;\n  border-radius:12px;\n  box-shadow:0 10px 30px rgba(0,0,0,0.12);\n}\n\n.neutron-caption{\n  font-size:14px;\n  color:#777;\n  margin-top:10px;\n  font-style:italic;\n}\n\n\/* =========================\n   RESPONSIVE\n========================= *\/\n@media(max-width:768px){\n  .neutron-container{\n    margin:20px;\n    padding:30px;\n  }\n\n  .neutron-title{\n    font-size:34px;\n  }\n\n  .neutron-subtitle{\n    font-size:22px;\n  }\n\n  .neutron-container p{\n    font-size:16px;\n  }\n}\n<\/style>\n\n<div class=\"neutron-container\">\n\n  <div class=\"neutron-title\">\n    Mod\u00e9rer un neutron libre\n  <\/div>\n\n  <div class=\"neutron-subtitle\">\n    Principe\n  <\/div>\n\n  <p>\n    La mod\u00e9ration est une op\u00e9ration qui consiste \u00e0 r\u00e9duire l\u2019\u00e9nergie cin\u00e9tique d\u2019un neutron.\n  <\/p>\n\n  <p>\n    L\u2019\u00e9nergie cin\u00e9tique initiale d\u2019un neutron lib\u00e9r\u00e9 du noyau est g\u00e9n\u00e9ralement de l\u2019ordre de quelques MeV.\n  <\/p>\n\n  <p>\n    Pour la r\u00e9duire \u00e0 quelques meV (~10<sup>-3<\/sup> eV), le neutron doit subir des collisions avec des noyaux l\u00e9gers.\n  <\/p>\n\n  <p>\n    Le transfert d\u2019\u00e9nergie d\u00e9pend du rapport de masse A entre le noyau cible et le neutron.\n  <\/p>\n\n  <div class=\"neutron-formula\">\n    (\u0394E \/ E) = f(A, \u03b8)\n  <\/div>\n\n  <p>\n    L\u2019\u00e9nergie cin\u00e9tique du neutron apr\u00e8s collision est minimale pour \u03b8 = 180\u00b0.\n  <\/p>\n\n  <div class=\"neutron-formula\">\n    E<sub>final<\/sub> = E<sub>initial<\/sub> \u00d7 ((A \u2212 1)\/(A + 1))\u00b2\n  <\/div>\n\n  <div class=\"neutron-image\">\n    <img decoding=\"async\" src=\"IMAGE_MODERATION_NEUTRONS.jpg\" alt=\"Mod\u00e9ration des neutrons\">\n    <div class=\"neutron-caption\">\n      R\u00e9duction progressive de l\u2019\u00e9nergie des neutrons par collisions successives.\n    <\/div>\n  <\/div>\n\n  <p>\n    Plus les noyaux ont une masse proche de celle du neutron, plus la r\u00e9duction d\u2019\u00e9nergie est efficace \u00e0 chaque collision.\n  <\/p>\n\n  <p>\n    Pour mod\u00e9rer un neutron, il doit subir plusieurs dizaines de collisions successives.\n  <\/p>\n\n<\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Mod\u00e9rer un neutron libre Principe La mod\u00e9ration est une op\u00e9ration qui consiste \u00e0 r\u00e9duire l\u2019\u00e9nergie cin\u00e9tique d\u2019un neutron. L\u2019\u00e9nergie cin\u00e9tique initiale d\u2019un neutron lib\u00e9r\u00e9 du noyau est g\u00e9n\u00e9ralement de l\u2019ordre de quelques MeV. Pour la r\u00e9duire \u00e0 quelques meV (~10-3 eV), le neutron doit subir des collisions avec des noyaux l\u00e9gers. Le transfert d\u2019\u00e9nergie d\u00e9pend [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-262","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.icone-neutron.fr\/fr\/wp-json\/wp\/v2\/pages\/262","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.icone-neutron.fr\/fr\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www.icone-neutron.fr\/fr\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www.icone-neutron.fr\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.icone-neutron.fr\/fr\/wp-json\/wp\/v2\/comments?post=262"}],"version-history":[{"count":12,"href":"https:\/\/www.icone-neutron.fr\/fr\/wp-json\/wp\/v2\/pages\/262\/revisions"}],"predecessor-version":[{"id":3331,"href":"https:\/\/www.icone-neutron.fr\/fr\/wp-json\/wp\/v2\/pages\/262\/revisions\/3331"}],"wp:attachment":[{"href":"https:\/\/www.icone-neutron.fr\/fr\/wp-json\/wp\/v2\/media?parent=262"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}