HANGEN CIKIN DALMA DA MUON DA LASER YA SAMAR

Muon ɗan uwa ne mai nauyi na electron. Saboda nauyinsa da ya fi yawa sosai, yana rasa ƙaramin ƙarfi (energy) lokacin da yake ratsa abu, kuma yana iya ratsa dutse ko ƙarfe masu kauri ƙwarai.

Wannan shi ne tushen muography: ɗaukar “hoton X-ray” na manyan abubuwa ko masu nauyi da muon. Ya bayyana wani babban rami a cikin dala ta Khufu a 2017, kuma an yi amfani da shi wajen binciken duwatsu masu aman wuta kamar Asama da Etna, ma’adinai, ramukan layin dogo, ƙanƙarar dutse (glaciers) da kwantenonin kaya.

Iyakar muon na sama

Har zuwa yanzu, muography ta dogara ne kawai ga muon na sararin samaniya, waɗanda ake samarwa ta halitta idan hasken sararin samaniya (cosmic rays) ya bugi sararin iska. Kwararar su ƙarama ce — kusan muon ɗaya a kowace santimita murabba’i a daƙiƙa — don haka ɗaukar hoto yana daɗewa. Galibi daga sama suke zuwa, kuma babu wanda ke sarrafa ƙarfinsu ko alƙiblarsu.

Madadin: samar da hasken muon na wucin gadi da laser. “Hanzartawa ta igiyar bayan laser” (laser wakefield acceleration) na iya tuƙa electron zuwa kusan GeV 10 cikin ’yan santimita na iska. Idan waɗannan electron suka bugi wani abu mai ƙarfi, suna samar da muon. An tabbatar da muon da laser ya samar a karon farko a 2025, a Shanghai da kuma a laser BELLA na Berkeley — amma an gano su a kaikaice kawai.

Gwajin

An yi aikin a ELI-NP (Extreme Light Infrastructure – Nuclear Physics) da ke Măgurele, Romania, da reshen laser ɗinsa mai ƙarfin petawatt 10: joule 230 cikin femtosecond 23, harbi ɗaya a minti a mafi yawa. Aikin ya yi amfani da harbi 230.

Wani abin hari na iska mai tsawon mm 60 ya samar da electron har zuwa GeV 8.
Sun bugi tubalin dalma mai girman 40 × 40 × 50 cm. A can, hasken gamma ya samar da nau’i-nau’i na muon da antimuon (tsarin Bethe–Heitler).
Garkuwa mai nauyi — santimita 100 na polyethylene, santimita 60 na paraffin, dalma, da bangon siminti mai ƙarfe mai kaurin mita 2 — ta tare neutron da hasken gamma da ba a so.
Na’urorin ganowa uku da aka ƙera don muography sun naɗi hasken. Ɗaya daga cikinsu, µ36, an ɗora shi a cikin mota (van) aka kai shi nisan mita 20, 29 da 42 daga tushen, har zuwa mita 6 a gefe.
Cikakkun kwaikwayon Monte Carlo (GEANT4) sun sake samar da dukkan tsarin, harbi bayan harbi, daga bakan electron da aka auna.

Abin da suka auna

Siffar hasken: wani ƙoli a tsakiyar gatari, faɗinsa mita 4.51 (a rabin tsayi) a mita 20 da mita 6.35 a mita 29 — kusurwar buɗewa ta kusan 12.6°. Kwaikwayon sun ba da mita 4.43 da mita 6.27.
A mita 20, kashi 86.9 % na ƙarfin da aka ajiye a na’urar ganowa daga muon ne, duk da cewa ƙwayoyin da ba a so sun fi yawa.
Ƙarfin muon: ’yan GeV, har zuwa 6–7. Muon suna buƙatar aƙalla GeV 1.5 don isa ga na’urorin ganowa.
Hoto: an ɗauki hoton wani abin dalma mai girman 20 × 25 × 100 cm, da aka ajiye a nisan mita 23 daga tushen, cikin harbin laser 30. Girmansa da aka sake ginawa: 22.5–25 cm — ainihin abin yana da kaurin santimita 25. Alamar da ke bayansa tana faɗuwa da kusan 26 %. Ƙudurin hoto: santimita 2.5, faɗin sandar na’urar ganowa ɗaya.
A cikin kwaikwayo, ba tare da muon ba, hasken gamma da neutron ba sa samar da wannan hoton, sai dai bango maras sauyi.

Bayan muon na sama

A cewar marubutan, wannan shi ne ɗaukar hoto na farko da hasken muon na wucin gadi wanda laser ke tuƙawa ya mamaye. Tushen wucin gadi yana kawo kwarara mai ƙarfi, da sarrafa alƙibla da ƙarfi — babu sauran jiran sama. Zai kuma iya taimakawa a binciken juyin muon (muon spin spectroscopy) da nazarin neutrino. Ayyukan gaba suna nufin ƙarfin electron mafi girma da na’urorin ganowa da aka ƙera don kwarara mai yawa.