[ I-Dark current ] – Ingabe ukukhanya okuphansi okumnyama kubalulekile ezithombeni zami? |

Umsinga omnyamaiwumthombo womsindo wekhamera oncike kuzinga lokushisa nesikhathi sokuchayeka, ukalwa ngama-electron ngephikseli ngayinye, ngesekhondi ngayinye yesikhathi sokuchayeka. Kuzinhlelo zokusebenza ezisebenzisa izikhathi zokuchayeka ezingaphansi kwesekhondi elilodwa, namandla amnyama angaphansi kuka-1e-/p/s, ngokuvamile zingazitshwa ekubalweni kwesilinganiso sesignali-kuya-nomsindo.

Isibonelo, ngenani lamanje elimnyama elingu-0.001 e/p/s, izikhathi zokuchayeka ezingu-1ms noma amasekhondi angu-60 zombili ziholela ekunikeleni komsindo onganakwa, lapho inani lomsindo linikezwa inani lamanje elimnyama eliphindwe isikhathi sokuchayeka, konke ngaphansi kwempande eyisikwele. Nokho, ikhamera ehlukile ene-2e-/p/s ekuchayekeni kwama-60s izonikela √120 = 11e- eyengeziwe yomsindo wamanje omnyama, ongase ubaluleke kakhulu kunomsindo ofundiwe emazingeni aphansi okukhanya. Noma kunjalo, ekuchayekeni okungu-1ms, naleli zinga eliphakeme lamanje elimnyama ngeke libe yinto engasho lutho.

Umfanekiso 1 : Umfanekiso 1(a) uvela kukhamera ye-CMOS epholile yaseTucsenFL 20BWukuthi umsinga omnyama uphansi njengo-0.001e/pixel/s. Umfanekiso 1(b) ukhombisa ukuthi uMdwebo 1(a) unawoa isizinda esihle kakhuluaIcishe ivikeleke emsindweni wamanje omnyama nakuba isikhathi sokuchayeka side njengama-10s.

Umsindo wamanje omnyama ubangelwa ukunyakaza okushisayo kwama-electron ngaphakathi kwenzwa yekhamera. Wonke ama-athomu azwa ukunyakaza kokudlidliza okushisayo, futhi ngezinye izikhathi i-electron 'ingagxuma' iphume endaweni engaphansi yenzwa yekhamera iye emthonjeni wephikseli lapho kugcinwa khona ama-photoelectron atholiwe. Akunakwenzeka ukuhlukanisa phakathi kwalawa ma-electron 'ashisayo' nama-electron avele ngokutholwa ngempumelelo kwe-photon. Ngesikhathi sokuchayeka kwesithombe, lawa ma-electron ashisayo angakheka, okunomthelela kusignali yamanje emnyama yangemuva. Nokho, inombolo enembile yama-electron ayihleliwe, okuholela ekunikeleni komsindo wamanje omnyama. Ekupheleni kokuchayeka, zonke izindleko zikalwa zisuliwe kuphikseli elungele ukuchayeka okulandelayo.

Umsindo wamanje omnyama uncike kuzinga lokushisa, kodwa futhi uncike kakhulu ekwakhiweni kwenzwa yekhamera nesakhiwo kanye nogesi wekhamera, ngakho-ke ungahluka kakhulu ukusuka kukhamera ukuya kukhamera ngezinga lokushisa elifanayo lenzwa.

Ingabe ukukhanya okuphansi okumnyama kubalulekile ezithombeni zami?Ukuthi inani lamanje elimnyama elinikeziwe lizonikela ngokuphawulekayo esilinganisweni sesignali-kumsindo wezithombe zakho kanye nekhwalithi yesithombe incike ngokuphelele esimweni sakho sesithombe.

Ezimeni zokuthwebula ezikhanyayo ezinezinkulungwane zama-photon ngephikseli ngalinye ngemva kokuchayeka kwekhamera, ubumnyama mancane amathuba okuba bubonakale ngekhwalithi yesithombe ngaphandle uma ukuchayekamama-es made kakhulu (amashumi amasekhondi ukuya emaminithini) njengakuzinhlelo zokusebenza zesayensi yezinkanyezi.