{"product_id":"chicago-pile-1-plate-049-physics-poster","title":"Chicago Pile-1 – Plate 049 Physics Poster","description":"\u003cp\u003ePlate 49 speaks for itself: \u003cem\u003e“Half a watt.”\u003c\/em\u003e\u003c\/p\u003e\u003ch3\u003eThe Physics\u003c\/h3\u003e\u003cp\u003eOn 2 December 1942, Fermi's team pulled the last control rod out of a graphite-and-uranium pile and the neutron count rose steadily: the first self-sustaining chain reaction.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003en(t) = n₀ e^((k − 1) t \/ ℓ)\u003c\/strong\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003en: neutron population, dimensionless\u003c\/li\u003e\n\u003cli\u003en₀: initial population\u003c\/li\u003e\n\u003cli\u003ek: effective multiplication factor, dimensionless\u003c\/li\u003e\n\u003cli\u003et: time, s\u003c\/li\u003e\n\u003cli\u003eℓ: mean neutron generation time, s\u003c\/li\u003e\n\u003c\/ul\u003e\u003cp\u003e2 Dec 1942: k just above 1. About ½ W; ~200 W on 12 Dec.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eHonest caveat:\u003c\/em\u003e The simple exponential ignores delayed neutrons, which in practice set how slowly a reactor near k = 1 responds.\u003c\/p\u003e\u003ch3\u003eSources\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eE. Fermi, Am. J. Phys. 20, 536 (1952).\u003c\/li\u003e\n\u003cli\u003eUS DOE, The First Reactor (DOE\/NE-0046).\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eOn the poster\u003c\/h3\u003e\u003cp\u003ePlate 049, “Chicago Pile-1”: the pixel-art plate with its slogan “Half a watt.”, the key equation and the facts panel shown above. Pixelated Physics. Physics. Personified.\u003c\/p\u003e","brand":"Printify","offers":[{"title":"9'' x 12\" (Vertical) \/ Matte","offer_id":50962274943079,"sku":"21080384924835004121","price":19.99,"currency_code":"USD","in_stock":true},{"title":"9'' x 12\" (Vertical) \/ Fine Art","offer_id":50962274975847,"sku":"27877917826764017808","price":29.99,"currency_code":"USD","in_stock":true},{"title":"9'' x 12\" (Vertical) \/ Semi Glossy","offer_id":50962275008615,"sku":"42295201947353980165","price":19.99,"currency_code":"USD","in_stock":true},{"title":"18″ x 24″ (Vertical) \/ Fine Art","offer_id":50962275041383,"sku":"17177233168075922299","price":44.99,"currency_code":"USD","in_stock":true},{"title":"18″ x 24″ (Vertical) \/ Semi Glossy","offer_id":50962275074151,"sku":"16143123214430025915","price":29.99,"currency_code":"USD","in_stock":true},{"title":"18″ x 24″ (Vertical) \/ Matte","offer_id":50962275106919,"sku":"21338134772510541070","price":29.99,"currency_code":"USD","in_stock":true},{"title":"36'' x 48\" (Vertical) \/ Matte","offer_id":50962275139687,"sku":"99611337390237265764","price":69.99,"currency_code":"USD","in_stock":true},{"title":"36'' x 48\" (Vertical) \/ Fine Art","offer_id":50962275172455,"sku":"25828671205282740736","price":119.99,"currency_code":"USD","in_stock":true},{"title":"36'' x 48\" (Vertical) \/ Semi Glossy","offer_id":50962275205223,"sku":"13204576054439887448","price":69.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0596\/8746\/9159\/files\/1282437938811342268_2048.jpg?v=1793634706","url":"https:\/\/pixelatedphysics.com\/it\/products\/chicago-pile-1-plate-049-physics-poster","provider":"Pixelated Physics","version":"1.0","type":"link"}