{"id":156646,"date":"2025-08-18T20:50:09","date_gmt":"2025-08-18T20:50:09","guid":{"rendered":"https:\/\/www.europesays.com\/us\/156646\/"},"modified":"2025-08-18T20:50:09","modified_gmt":"2025-08-18T20:50:09","slug":"2025-one-hertz-challenge-timekeeping-at-one-becquerel","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/156646\/","title":{"rendered":"2025 One Hertz Challenge: Timekeeping At One Becquerel"},"content":{"rendered":"

The Becquerel (Bq) is an SI unit of radioactivity: one becquerel is equivalent to one radioactive decay per second. That absolutely does not make it equivalent to one hertz \u2014 the random nature of radioactive decay means you\u2019ll never get one pulse every second \u2014 but it does make it interesting. [mihai.cuciuc] certainly thought so, when he endeavored to create a clock that would tick at one becquerel.<\/a><\/p>\n

The result is an interesting version of a Vetinari Clock<\/a>, first conceived of by [Terry Pratchett] in his\u00a0Discworld books. In the books, the irregular tick of the clock is used by Lord Vetinari as a form of psychological torture. For some reason, imposing this torture on ourselves<\/a> has long been popular amongst hackers<\/a>.<\/p>\n

Without an impractical amount of shielding, any one-becquerel source would be swamped by background radiation, so [mihai] had to get creative. Luckily, he is the creator of the Pomelo gamma-ray spectroscope,<\/a> which allowed him to be discriminating. He\u2019s using an Am-241 source, but just looking for the characteristic 59.5 KeV gamma rays was not going to cut it at such a low count rate. Instead he\u2019s using two of the Pomelo solid-state scintillation as a coincidence detector, with one tuned for the Am-241\u2019s alpha emissions. When both detectors go off simultaneously, that counts as an event and triggers the clock to tick.<\/p>\n

How he got exactly one becquerel of activity is a clever hack, too. The Am-241 source he has is far more active than one decay per second, but by varying the distance from the gamma detector he was able to cut down to one detection per second using the inverse square law and the shielding provided by Earth\u2019s atmosphere. The result is a time signal that is a stable one hertz\u2026 if averaged over a long enough period. For now, anyway. As the Am-241 decays away, its activity decreases, and [mihai] admits the clock loses about 0.4 seconds per day.<\/p>\n

While we won\u2019t be giving the prize for accuracy in this contest, we are sure Lord Vetinari would be proud. The Geiger-counter sound effect you can hear in the demo video embedded below is great touch. It absolutely increases the psychic damage this cursed object inflicts.<\/p><\/p>\n","protected":false},"excerpt":{"rendered":"The Becquerel (Bq) is an SI unit of radioactivity: one becquerel is equivalent to one radioactive decay per…\n","protected":false},"author":3,"featured_media":156647,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[25],"tags":[492,159,67,132,68],"class_list":{"0":"post-156646","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-physics","8":"tag-physics","9":"tag-science","10":"tag-united-states","11":"tag-unitedstates","12":"tag-us"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/115051746453700825","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/156646","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=156646"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/156646\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/156647"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=156646"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=156646"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=156646"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}