{"product_id":"dynodra-photomultiplier","title":"Dynodra – The Photomultiplier \/ ln G = N ln δ Physics Sticker","description":"\u003cp\u003eDynodra, a hooded tube-wizard, sends a single spark up a staircase of glowing steps, and it grows brighter at every step.\u003c\/p\u003e\u003ch3\u003eThe Physics\u003c\/h3\u003e\u003cp\u003eA photomultiplier tube turns one photon into a measurable pulse. The photon frees an electron from the photocathode. It is then accelerated onto the first dynode, where it knocks out several secondary electrons. Each of those is accelerated onto the next dynode, and so on. With δ secondaries per electron at each of N stages, the gain multiplies.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eG = δ\u003csup\u003eN\u003c\/sup\u003e, so ln G = N ln δ\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eG: overall electron gain\u003c\/li\u003e\n\u003cli\u003eδ: secondary-emission ratio per dynode\u003c\/li\u003e\n\u003cli\u003eN: number of dynodes\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003eWith δ = 4 and N = 10, G = 4¹⁰ = 1,048,576, about 10⁶ electrons from one. That is enough to make a pulse from a single photon.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eHonest caveat:\u003c\/em\u003e It multiplies electrons, not photons: only the first step involves light, and many photons free no electron at all. δ is an average that depends on the voltage at each stage, so the real gain fluctuates from pulse to pulse.\u003c\/p\u003e\u003ch3\u003eOn the sticker\u003c\/h3\u003e\u003cp\u003eDynodra raises a hand as a cyan spark climbs a glowing staircase of dynode steps. Printed text: \u003cstrong\u003eDYNODRA\u003c\/strong\u003e with the line \u003cstrong\u003eln G = N ln δ\u003c\/strong\u003e. Pixel-art kiss-cut vinyl sticker, white, in 2″, 3″, 4″ and 6″ sizes.\u003c\/p\u003e","brand":"Printify","offers":[{"title":"2\" × 2\" \/ White","offer_id":50963985530983,"sku":"13246289186634206070","price":4.99,"currency_code":"USD","in_stock":true},{"title":"3\" × 3\" \/ White","offer_id":50963985563751,"sku":"12010560075086908403","price":6.99,"currency_code":"USD","in_stock":true},{"title":"4\" × 4\" \/ White","offer_id":50963985596519,"sku":"16158455459921559139","price":8.99,"currency_code":"USD","in_stock":true},{"title":"6\" × 6\" \/ White","offer_id":50963985629287,"sku":"44887053478750437035","price":11.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/8746\/9159\/files\/12694103847717338101_1200.jpg?v=1793657715","url":"https:\/\/pixelatedphysics.com\/pl\/products\/dynodra-photomultiplier","provider":"Pixelated Physics","version":"1.0","type":"link"}