Laser na bugun jini na X-ray na aji TW attosecond

Laser na bugun jini na X-ray na aji TW attosecond
Attosecond X-raybugun jini lasertare da ƙarfin aiki mai yawa da ɗan gajeren lokaci na bugun jini sune mabuɗin cimma nasarar gwajin spectroscopy mara layi da kuma hoton X-ray diffraction. Ƙungiyar binciken a Amurka ta yi amfani da tsarin matakai biyu.Lasers na lantarki marasa X-raydon fitar da bugun attosecond mai rarrabuwa. Idan aka kwatanta da rahotannin da ake da su, matsakaicin ƙarfin kololuwar bugun yana ƙaruwa da tsari na girma, matsakaicin ƙarfin kololuwar shine 1.1 TW, kuma matsakaicin kuzarin ya fi 100 μJ. Binciken ya kuma bayar da shaida mai ƙarfi game da halayen superradiation kamar soliton a cikin filin X-ray.Lasers masu ƙarfisun jagoranci sabbin fannoni da yawa na bincike, gami da kimiyyar lissafi mai zurfi, attosecond spectroscopy, da kuma na'urorin haɓaka barbashi na laser. Daga cikin dukkan nau'ikan lasers, ana amfani da X-rays sosai a cikin ganewar likita, gano lahani a masana'antu, duba lafiya da binciken kimiyya. Laser ɗin X-ray free-electron (XFEL) na iya ƙara ƙarfin X-ray mai tsayi da yawa idan aka kwatanta da sauran fasahar samar da X-ray, don haka yana faɗaɗa aikace-aikacen X-ray zuwa fagen spectroscopy mara layi da hoton diffraction guda ɗaya inda ake buƙatar babban iko. Nasarar XFEL ta attosecond ta kwanan nan babban nasara ce a kimiyya da fasaha ta attosecond, tana ƙara ƙarfin kololuwar da ake da shi da fiye da umarni shida na girma idan aka kwatanta da tushen X-ray na benchtop.

Lasers na lantarki kyautazai iya samun kuzarin bugun jini da yawa na girma sama da matakin fitar da iska ta hanyar amfani da rashin kwanciyar hankali na gama gari, wanda ke faruwa ne sakamakon ci gaba da hulɗar filin radiation a cikin hasken lantarki mai alaƙa da kuma oscillator na maganadisu. A cikin kewayon hasken X-ray mai tauri (kimanin 0.01 nm zuwa 0.1 nm wavelength), ana samun FEL ta hanyar matsewa da dabarun haɗakarwa bayan cikawa. A cikin kewayon hasken X-ray mai laushi (kimanin 0.1 nm zuwa 10 nm wavelength), ana aiwatar da FEL ta hanyar fasahar yanka sabo-yanki. Kwanan nan, an ba da rahoton cewa bugun attosecond tare da ƙarfin kololuwa na 100 GW ana samar da shi ta amfani da hanyar haɓaka fitar da iska mai saurin amsawa ta kai tsaye (ESASE).

Ƙungiyar binciken ta yi amfani da tsarin ƙara girma na matakai biyu bisa ga XFEL don ƙara yawan fitowar bugun X-ray mai laushi daga linac coherenttushen haskezuwa matakin TW, wani tsari na girma fiye da sakamakon da aka ruwaito. An nuna saitin gwaji a Hoto na 1. Dangane da hanyar ESASE, ana daidaita mai fitar da hasken photocathode don samun hasken lantarki mai ƙarfin lantarki mai yawa, kuma ana amfani da shi don samar da bugun X-ray na attosecond. Bugawar farko tana nan a gefen gaba na bugun wutar lantarki, kamar yadda aka nuna a kusurwar hagu ta sama na Hoto na 1. Lokacin da XFEL ya kai ga cikawa, hasken lantarki yana jinkiri idan aka kwatanta da hasken X ta hanyar matsewar maganadisu, sannan bugun yana hulɗa da hasken lantarki (sabon yanki) wanda ba a canza shi ta hanyar daidaitawar ESASE ko laser FEL ba. A ƙarshe, ana amfani da na'urar haɗa maganadisu ta biyu don ƙara faɗaɗa hasken X ta hanyar hulɗar bugun attosecond tare da sabon yanki.

FIG. 1 Zane na na'urar gwaji; Zane yana nuna sararin lokaci na tsayi (zanen makamashin lokaci na electron, kore), bayanin halin yanzu (shuɗi), da kuma hasken da aka samar ta hanyar ƙarawa tsari na farko (shuɗi). XTCAV, ramin juyawa na X-band; cVMI, tsarin hoton taswirar sauri na coaxial; FZP, na'urar auna farantin Fresnel

An gina dukkan bugun attosecond daga hayaniya, don haka kowace bugun tana da halaye daban-daban na spectral da lokaci-yanki, waɗanda masu binciken suka bincika dalla-dalla. Dangane da spectra, sun yi amfani da na'urar aunawa ta farantin Fresnel don auna spectra na bugun kowane ɗaya a tsayin undolator iri ɗaya, kuma sun gano cewa waɗannan spectra suna kiyaye santsi na raƙuman ruwa koda bayan ƙarawa na biyu, yana nuna cewa bugun ya kasance iri ɗaya. A cikin yankin lokaci, ana auna gefen kusurwa kuma an siffanta yanayin raƙuman ruwa na lokacin bugun. Kamar yadda aka nuna a Hoto na 1, bugun X-ray ya haɗu da bugun laser infrared mai zagaye mai polarized. Hotunan lantarki da aka ionized ta bugun X-ray zai samar da strikes a cikin alkiblar da ta saba da ƙarfin vector na laser infrared. Saboda filin lantarki na laser yana juyawa da lokaci, rarrabawar motsi na photoelectron ana ƙaddara shi ta hanyar lokacin fitar da lantarki, kuma an kafa dangantakar da ke tsakanin yanayin kusurwa na lokacin fitar da haske da rarrabawar motsi na photoelectron. Ana auna rarrabawar motsin hasken photoelectron ta amfani da na'urar auna taswirar sauri ta coaxial. Dangane da sakamakon rarrabawa da kuma spectral, ana iya sake gina tsarin raƙuman lokaci na bugun attosecond. Hoto na 2 (a) yana nuna rarrabawar tsawon bugun, tare da matsakaicin 440 kamar yadda. A ƙarshe, an yi amfani da na'urar gano iskar gas don auna kuzarin bugun, kuma an ƙididdige taswirar watsawa tsakanin ƙarfin bugun kololuwa da tsawon bugun kamar yadda aka nuna a Hoto na 2 (b). Tsarin guda uku sun dace da yanayin mayar da hankali kan hasken wutar lantarki daban-daban, yanayin haɗin waver da yanayin jinkirin matsewar maganadisu. Tsarin guda uku sun samar da matsakaicin kuzarin bugun 150, 200, da 260 µJ, bi da bi, tare da matsakaicin ƙarfin kololuwa na 1.1 TW.

Hoto na 2. (a) Histogram ɗin rarrabawa na rabin tsayi Cikakken tsawon bugun zuciya (FWHM); (b) Tsarin watsawa wanda ya yi daidai da ƙarfin kololuwa da tsawon bugun zuciya

Bugu da ƙari, binciken ya kuma lura a karon farko da abin da ya faru na fitar da iska mai kama da soliton a cikin X-ray band, wanda ke bayyana a matsayin raguwar bugun jini akai-akai yayin ƙara girma. Yana faruwa ne sakamakon hulɗa mai ƙarfi tsakanin electrons da radiation, tare da saurin canja wurin kuzari daga electron zuwa kan bugun X-ray sannan ya koma electron daga wutsiyar bugun. Ta hanyar zurfafa bincike kan wannan lamari, ana sa ran bugun X-ray mai ɗan gajeren lokaci da ƙarfin kololuwa mafi girma za a iya ƙara fahimtarsa ​​ta hanyar faɗaɗa tsarin ƙara girma na superradiation da kuma cin gajiyar rage bugun jini a yanayin soliton.