{"id":36248,"date":"2019-10-31T22:10:29","date_gmt":"2019-10-31T19:10:29","guid":{"rendered":"https:\/\/prohoster.info\/blog\/mal-da-udal-miniatyurnyj-linejnyj-uskoritel-chastits-postavivshij-novyj-rekord\/"},"modified":"2019-10-31T22:10:29","modified_gmt":"2019-10-31T19:10:29","slug":"mal-da-udal-miniatyurnyj-linejnyj-uskoritel-chastits-postavivshij-novyj-rekord","status":"publish","type":"post","link":"https:\/\/prohoster.info\/ro\/blog\/news\/mal-da-udal-miniatyurnyj-linejnyj-uskoritel-chastits-postavivshij-novyj-rekord","title":{"rendered":"Mic, dar puternic: acceleratorul liniar de particule miniatural care a stabilit un nou record","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"<p><img decoding=\"async\" alt=\"Mic, dar puternic: acceleratorul liniar de particule miniatural care a stabilit un nou record\" src=\"\/wp-content\/uploads\/2019\/07\/6df72c15b548271b03607338af4348b1.png\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<br \/>\nPrincipiul cunoscut \u201emai mult \u00eenseamn\u0103 mai puternic\u201d s-a stabilit de mult timp \u00een multe domenii ale vie\u021bii sociale, inclusiv \u00een \u0219tiin\u021b\u0103 \u0219i tehnologie. Cu toate acestea, \u00een realit\u0103\u021bile moderne, tot mai des \u00eent\u00e2lnim implementarea practic\u0103 a zicalei \u201emic, dar puternic\u201d. Aceasta se manifest\u0103 at\u00e2t \u00een computere, care anterior ocupau o \u00eentreag\u0103 camer\u0103, dar acum \u00eencape \u00een palma unui copil, c\u00e2t \u0219i \u00een acceleratoarele de particule. Da, da, v\u0103 aminti\u021bi de marele accelerator de particule (LHC), dimensiunile sale impresionante (26.659 m lungime) fiind literalmente specificate \u00een numele s\u0103u? A\u0219adar, acest lucru face parte din trecut, conform cercet\u0103torilor de la DESY, care au dezvoltat o versiune miniatural\u0103 a acceleratorului, care nu ced\u0103 \u00een fa\u021ba predecesorului s\u0103u de dimensiuni normale. Mai mult dec\u00e2t at\u00e2t, acceleratorul mini a stabilit chiar un nou record mondial \u00een r\u00e2ndul acceleratorilor teraherc, dubl\u00e2nd energia electronilor injecta\u021bi. Cum a fost dezvoltat acceleratorul miniatural, care sunt principiile sale de func\u021bionare \u0219i ce au ar\u0103tat experimentele practice? Aceste \u00eentreb\u0103ri ne va ajuta s\u0103 le descoperim raportul grupului de cercetare. S\u0103 \u00eencepem.<noindex><a rel=\"nofollow\" name=\"habracut\"><\/a><\/noindex><\/p>\n<h3>Baza cercet\u0103rii<\/h3>\n<p>\nConform lui Dongfang Zhang \u0219i colegilor s\u0103i de la DESY (German Electron Synchrotron), care au dezvoltat acceleratorul mini, sursele ultrarapide de electroni joac\u0103 un rol incredibil de important \u00een via\u021ba societ\u0103\u021bii moderne. Multe dintre acestea se manifest\u0103 \u00een medicin\u0103, dezvoltarea electronicii \u0219i \u00een cercet\u0103ri \u0219tiin\u021bifice. Cea mai mare problem\u0103 a acceleratorilor liniari actuali, care folosesc generatoare de radiofrecven\u021b\u0103, este costul lor ridicat, complexitatea infrastructurii \u0219i cerin\u021bele mari \u00een ceea ce prive\u0219te energia consumat\u0103. Aceste dezavantaje limiteaz\u0103 semnificativ accesibilitatea acestor tehnologii pentru un public mai larg. <\/p>\n<p>Aceste probleme evidente reprezint\u0103 un stimul excelent pentru dezvoltarea dispozitivelor a c\u0103ror dimensiuni nu vor provoca groaz\u0103, la fel cum nu va face nici consumul de energie.<\/p>\n<p>Printre nout\u0103\u021bile relative din acest domeniu se num\u0103r\u0103 acceleratorii teraherc, care au o serie de \u201eavantaje\u201d:<\/p>\n<ul>\n<li>se a\u0219teapt\u0103 ca undele scurte \u0219i impulsurile scurte de radia\u021bie teraherc s\u0103 permit\u0103 cre\u0219terea semnificativ\u0103 a pragului <i>de defect*<\/i>, cauzat de c\u00e2mp, ceea ce va permite cre\u0219terea gradientelor de accelerare;<\/li>\n<\/ul>\n<blockquote><p><b>Defect electric*<\/b> \u2014 o cre\u0219tere brusc\u0103 a curentului electric la aplicarea unei tensiuni mai mari dec\u00e2t cea critic\u0103.<\/p><\/blockquote>\n<ul>\n<li>disponibilitatea unor metode eficiente de generare a radia\u021biei terahertz cu c\u00e2mpuri \u00eenalte permite sincronizarea intern\u0103 \u00eentre electroni \u0219i c\u00e2mpurile de excita\u021bie;<\/li>\n<li>pentru crearea acestor dispozitive pot fi utilizate metode clasice, dar costul, timpul de produc\u021bie \u0219i dimensiunile vor fi semnificativ reduse. <\/li>\n<\/ul>\n<p>Cercet\u0103torii consider\u0103 c\u0103 acceleratorul lor terahertz la scar\u0103 milimetric\u0103 este un compromis \u00eentre acceleratoarele obi\u0219nuite, care sunt disponibile \u00een prezent, \u0219i micro-acceleratoarele, care sunt \u00een dezvoltare, dar au multe deficien\u021be din cauza dimensiunilor lor extrem de reduse.<\/p>\n<p>Cercet\u0103torii nu contest\u0103 faptul c\u0103 tehnologia acceler\u0103rii terahertz este \u00een dezvoltare de ceva vreme. Cu toate acestea, \u00een opinia lor, \u00een acest domeniu exist\u0103 \u00een continuare o mul\u021bime de aspecte care nu au fost studiate, verificate sau implementate. <\/p>\n<p>\u00cen lucrarea sa, pe care o discut\u0103m ast\u0103zi, oamenii de \u0219tiin\u021b\u0103 demonstreaz\u0103 capabilit\u0103\u021bile STEAM (<i>accelerator \u0219i manipulator de electroni terahertz segmentat<\/i>) \u2014 un accelerator \u0219i manipulator de electroni terahertz segmentat. STEAM permite reducerea lungimii fasciculului de electroni la o durat\u0103 sub-picoscuri, asigur\u00e2nd astfel un control femtosecund asupra fazei de accelerare.<\/p>\n<p>S-a reu\u0219it ob\u021binerea unui c\u00e2mp de accelerare de 200 MV\/m (MV \u2014 megavolt), ceea ce duce la un accelerator terahertz record de &gt; 70 keV (kiloelectronvol\u021bi) de la fasciculul de electroni implantat cu energie de 55 keV. Astfel s-au ob\u021binut electroni accelera\u021bi p\u00e2n\u0103 la 125 keV.<\/p>\n<h3>Structura dispozitivului \u0219i implementarea acestuia<\/h3>\n<p>\n<img decoding=\"async\" alt=\"Mic, dar puternic: acceleratorul liniar de particule miniatural care a stabilit un nou record\" src=\"\/wp-content\/uploads\/2019\/07\/581d753c9734024561fa600f132a7e8d.png\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<i>Imaginea \u21161: schema dispozitivului studiat.<\/i><\/p>\n<p><img decoding=\"async\" alt=\"Mic, dar puternic: acceleratorul liniar de particule miniatural care a stabilit un nou record\" src=\"\/wp-content\/uploads\/2019\/07\/d404ba9fe59504ac46e730aefbbf2134.png\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<i>Imaginea \u21161-2: a \u2014 schema structurii segmentate cu 5 straturi dezvoltat\u0103, b \u2014 raportul dintre accelerarea calculat\u0103 \u0219i direc\u021bia de propagare a electronilor.<\/i><\/p>\n<p>Fasciculele de electroni (55 keV) sunt generate din <i>pu\u0219ca electronic\u0103*<\/i> \u0219i sunt injectate \u00een STEAM-buncher terahertz (compresor de fascicul), trec\u00e2nd apoi \u00een STEAM-linac (<i>accelerator liniar*<\/i>).<\/p>\n<blockquote><p><b>Pu\u0219ca electronic\u0103*<\/b> \u2014 un dispozitiv de generare a fasciculului de electroni cu configura\u021bia \u0219i energia necesare.<\/p><\/blockquote>\n<blockquote><p><b>Acceleratorul liniar*<\/b> \u2014 un accelerator \u00een care particulele \u00eenc\u0103rcate traverseaz\u0103 structura doar o singur\u0103 dat\u0103, ceea ce distinge acceleratorul liniar de cel ciclic (de exemplu, LHC). <\/p><\/blockquote>\n<p>Ambele dispozitive STEAM primesc impulsuri terahertz de la un singur laser cu lumin\u0103 infra-ro\u0219ie apropiat\u0103 (NIR), care de asemenea activeaz\u0103 fotocatalizatorul unui tun de electroni, ceea ce conduce la sincronizarea intern\u0103 \u00eentre electroni \u0219i c\u00e2mpurile de accelerare. Impulsurile ultraviolete pentru fotoemisie pe fotocatalizator sunt generate prin dou\u0103 etape consecutive. <i>GVG*<\/i> lungimii de und\u0103 principale a luminii infraro\u0219ii apropiate. Acest proces transform\u0103 impulsul laserului cu o lungime de und\u0103 de 1020 nm mai \u00eent\u00e2i \u00een 510 nm, apoi \u00een 255 nm.<\/p>\n<blockquote><p><b>GVG*<\/b> (generarea celei de-a doua armonici optice) - procesul de combinare a fotonilor cu aceea\u0219i frecven\u021b\u0103 \u00een timpul interac\u021biunii cu un material non-linear, ceea ce duce la formarea de noi fotoni cu dubl\u0103 energie \u0219i frecven\u021b\u0103, precum \u0219i cu o lungime de und\u0103 de dou\u0103 ori mai mic\u0103.<\/p><\/blockquote>\n<p>Partea r\u0103mas\u0103 a fasciculului laser NIR este \u00eemp\u0103r\u021bit\u0103 \u00een 4 fascicule, care sunt utilizate pentru a genera patru impulsuri terahertz monociclare prin generarea de diferen\u021be \u00eentre frecven\u021bele impulsurilor.<\/p>\n<p>Dou\u0103 impulsuri terahertz sunt apoi trimise \u00een fiecare dispozitiv STEAM prin structuri simetrice de horn, care direc\u021bioneaz\u0103 energia terahertz \u00een zona de interac\u021biune perpendicular pe direc\u021bia de propagare a electronilor.<\/p>\n<p>C\u00e2nd electronii intr\u0103 \u00een fiecare dintre dispozitivele STEAM, ei sunt expu\u0219i componentelor electrice \u0219i magnetice. <i>for\u021ba Lorentz*<\/i>.<\/p>\n<blockquote><p><b>For\u021ba Lorentz*<\/b> - for\u021ba cu care c\u00e2mpul electromagnetic ac\u021bioneaz\u0103 asupra unei particule \u00eenc\u0103rcate.<\/p><\/blockquote>\n<p>\u00cen acest caz, c\u00e2mpul electric este responsabil pentru accelerare \u0219i decelerare, iar c\u00e2mpul magnetic provoac\u0103 devia\u021bii transversale.<\/p>\n<p><img decoding=\"async\" alt=\"Mic, dar puternic: acceleratorul liniar de particule miniatural care a stabilit un nou record\" src=\"\/wp-content\/uploads\/2019\/07\/6e56629be1c0de410ab1411baaceff14.png\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<i>Imaginea nr. 2<\/i><\/p>\n<p>A\u0219a cum vedem \u00een imagini, <b>2a<\/b> \u0219i <b>2b<\/b>, \u00een interiorul fiec\u0103rui dispozitiv STEAM, fasciculele terahertz sunt separate prin foi metalice sub\u021biri \u00een mai multe straturi de diferite grosimi, fiecare dintre ele ac\u021bion\u00e2nd ca un ghid de und\u0103, transport\u00e2nd o parte din energia total\u0103 \u00een zona de interac\u021biune. De asemenea, \u00een fiecare strat sunt prezente pl\u0103ci dielectrice pentru a sincroniza timpul de sosire al frontului terahertz <i>frontul de und\u0103*<\/i> cu frontul electronilor.<\/p>\n<blockquote><p><b>Frontul de und\u0103*<\/b> - suprafa\u021ba p\u00e2n\u0103 la care a ajuns unda.<\/p><\/blockquote>\n<p>Ambele dispozitive STEAM func\u021bioneaz\u0103 \u00een mod electric, adic\u0103 astfel \u00eenc\u00e2t s\u0103 produc\u0103 o suprapunere a c\u00e2mpului electric \u0219i o suprimare a c\u00e2mpului magnetic \u00een centrul zonei de interac\u021biune.<\/p>\n<p>\u00cen primul dispozitiv, electronii sunt calcula\u021bi \u00een func\u021bie de timp astfel \u00eenc\u00e2t s\u0103 treac\u0103 prin <i>intersec\u021bia zero*<\/i> c\u00e2mpului terahertz, unde gradientele temporale ale c\u00e2mpului electric sunt maximizate, iar c\u00e2mpul mediu este minimizat.<\/p>\n<blockquote><p><b>Intersec\u021bia zero*<\/b> \u2014 punctul \u00een care nu exist\u0103 tensiune.<\/p><\/blockquote>\n<p>Aceast\u0103 configura\u021bie provoac\u0103 accelerarea cozii fasciculului de electroni \u0219i \u00eencetinirea capului s\u0103u, ceea ce duce la focalizarea longitudinal\u0103 balistic\u0103 (<b>2a<\/b> \u0219i <b>2s<\/b>).<\/p>\n<p>\u00cen al doilea dispozitiv, sincronizarea electronului \u0219i a radia\u021biei terahertz este stabilit\u0103 astfel \u00eenc\u00e2t fasciculul de electroni s\u0103 experimenteze doar ciclul negativ al c\u00e2mpului electric terahertz. Aceast\u0103 configura\u021bie duce la o accelerare continu\u0103 pur\u0103 (<b>2b<\/b> \u0219i <b>2d<\/b>).<\/p>\n<p>Laserul cu radia\u021bie NIR este similar cu sistemul Yb:YLF r\u0103cit criogenic, care emite impulsuri optice cu o durat\u0103 de 1.2 ps \u0219i o energie de 50 mJ la o lungime de und\u0103 de 1020 nm \u0219i o frecven\u021b\u0103 de repetare de 10 Hz. Impulsi terahertz cu frecven\u021ba central\u0103 de 0.29 terahertz (perioada de 3.44 ps) sunt genera\u021bi prin metoda impulsului cu front \u00eenclinat.<\/p>\n<p>Pentru alimentarea bunc\u0103rului STEAM (compresorul de fascicul) au fost utilizate doar 2 x 50 nJ de energie terahertz, iar pentru STEAM-linac (accelerator liniar) au fost necesare 2 x 15 mJ.<\/p>\n<p>Diametrul orificiilor de intrare \u0219i ie\u0219ire ale ambelor dispozitive STEAM este de 120 \u03bcm.<\/p>\n<p>Compresorul de fascicul este proiectat cu trei straturi de \u00een\u0103l\u021bime egal\u0103 (0. 225 mm), echipate cu pl\u0103ci din cuar\u021b fuzionat (\u03f5r =4.41) de lungimi de 0.42 \u0219i 0.84 mm pentru controlul sincroniz\u0103rii temporale. \u00cen\u0103l\u021bimile egale ale straturilor compresorului reflect\u0103 faptul c\u0103 nu are loc accelerarea (<b>2s<\/b>).<\/p>\n<p>\u00cen schimb, \u00een acceleratorul liniar, \u00een\u0103l\u021bimile difer\u0103 \u2014 0.225, 0.225 \u0219i 0.250 mm (+ pl\u0103ci din cuar\u021b fuzionat de 0.42 \u0219i 0.84 mm). Cre\u0219terea \u00een\u0103l\u021bimii stratului explic\u0103 cre\u0219terea vitezei electronilor \u00een timpul acceler\u0103rii.<\/p>\n<p>Oamenii de \u0219tiin\u021b\u0103 subliniaz\u0103 c\u0103 num\u0103rul de straturi corespunde direct func\u021bionalit\u0103\u021bii fiec\u0103rui dintre cele dou\u0103 dispozitive. Pentru a atinge un grad mai \u00eenalt de accelerare, de exemplu, va fi nevoie de mai multe straturi \u0219i o alt\u0103 configura\u021bie a \u00een\u0103l\u021bimilor pentru optimizarea interac\u021biunii.<\/p>\n<h3>Rezultatele experimentelor practice<\/h3>\n<p>\n\u00cen primul r\u00e2nd, cercet\u0103torii reamintesc c\u0103, \u00een acceleratoarele tradi\u021bionale bazate pe radiofrecven\u021b\u0103, influen\u021ba duratei temporale a fasciculului de electroni introdus asupra propriet\u0103\u021bilor fasciculului accelerat este legat\u0103 de modificarea c\u00e2mpului electric, experimentat \u00een timpul interac\u021biunii de diferi\u021bi electroni din fascicul, care ajung \u00een momente diferite. Astfel, se poate presupune c\u0103 c\u00e2mpurile cu un gradient mai mare \u0219i fasciculele cu o durat\u0103 mai mare vor conduce la o dispersie mai mare a energiilor. Fasciculele introduse cu o durat\u0103 mare pot duce, de asemenea, la valori mai \u00eenalte. <i>emitan\u021be*<\/i>.<\/p>\n<blockquote><p><b>Emitan\u021b\u0103*<\/b> \u2014 spa\u021biul fazic pe care \u00eel ocup\u0103 un fascicul accelerat de particule \u00eenc\u0103rcate.<\/p><\/blockquote>\n<p>\u00cen cazul acceleratorului terahertz, perioada c\u00e2mpului de excita\u021bie este de aproximativ 200 de ori mai scurt\u0103. Prin urmare, <i>intensitatea*<\/i> c\u00e2mpului men\u021binut va fi de 10 ori mai mare. <\/p>\n<blockquote><p><b>Intensitatea c\u00e2mpului electric* <\/b> \u2014 indicator al c\u00e2mpului electric, egal cu raportul dintre for\u021ba aplicat\u0103 asupra unei sarcini punctuale sta\u021bionare, plasate \u00eentr-un anumit punct al c\u00e2mpului, \u0219i m\u0103rimea acestei sarcini. <\/p><\/blockquote>\n<p>Astfel, \u00een acceleratorul terahertz, gradien\u021bii c\u00e2mpului resim\u021bi\u021bi de electroni pot fi cu c\u00e2teva ordini de magnitudine mai mari dec\u00e2t \u00een dispozitivele obi\u0219nuite. Timpul \u00een care curburile c\u00e2mpului sunt vizibile va fi semnificativ mai mic. Deci, durata fasciculului de electroni introdus va avea o influen\u021b\u0103 mai pronun\u021bat\u0103.<\/p>\n<p>Oamenii de \u0219tiin\u021b\u0103 au decis s\u0103 testeze practic datele teoriei. Pentru aceasta, au introdus fascicule de electroni de diferite durate, care erau controlate prin comprimare folosind primul dispozitiv STEAM (STEAM-buncher).<\/p>\n<p><img decoding=\"async\" alt=\"Mic, dar puternic: acceleratorul liniar de particule miniatural care a stabilit un nou record\" src=\"\/wp-content\/uploads\/2019\/07\/1d15ed2cec289b62df3d7a8a1fc2962c.png\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<i>Imaginea nr. 3<\/i><\/p>\n<p>\u00cen cazul \u00een care compresorul nu era conectat la sursa de alimentare, fasciculele de electroni (55 keV) cu o sarcin\u0103 de \u223c1 fC (femtocoulomb) au parcurs aproximativ 300 mm de la pu\u0219ca electronic\u0103 la dispozitivul accelerator linie (STEAM-linac). Ace\u0219ti electroni s-au putut extinde sub influen\u021ba for\u021belor de sarcin\u0103 de spa\u021biu p\u00e2n\u0103 la o durat\u0103 de mai mult de 1000 fs (femtosecunde).<\/p>\n<p>Pentru o astfel de durat\u0103, fasciculul de electroni ocupa aproximativ 60% din semiperioada c\u00e2mpului de accelerare cu o frecven\u021b\u0103 de 1,7 ps, conduc\u00e2nd la un spectru energetic dup\u0103 accelerare cu un v\u00e2rf de 115 keV \u0219i o l\u0103\u021bime de jum\u0103tate de distribu\u021bie a energiei de peste 60 keV (<b>3a<\/b>).<\/p>\n<p>Pentru a compara aceste rezultate cu cele a\u0219teptate, a fost modelat\u0103 o situa\u021bie de propagare a electronilor printr-un accelerator liniar, c\u00e2nd electronii erau desincroniza\u021bi (adic\u0103, nu se potriveau) \u00een raport cu timpul optim de introducere. Calculul unei astfel de situa\u021bii a ar\u0103tat c\u0103 cre\u0219terea energiei electronilor depinde foarte mult de momentul introducerii, p\u00e2n\u0103 la dimensiuni temporale sub-picosecunde (<b>3b<\/b>). Deci, \u00eentr-o configurare optim\u0103, electronul va experimenta \u00eentreaga semiperioad\u0103 de accelerare a radia\u021biei terahertz \u00een fiecare strat (<b>3s<\/b>).<\/p>\n<p>Dac\u0103 electronii sosesc la momente diferite, ace\u0219tia experimenteaz\u0103 o accelerare mai mic\u0103 \u00een primul strat, ceea ce le necesit\u0103 mai mult timp pentru a-l traversa. Apoi, desincronizarea se intensific\u0103 \u00een straturile urm\u0103toare, ceea ce duce la o \u00eencetinire nedorit\u0103 (<b>3d<\/b>). <\/p>\n<p>Pentru a minimiza efectul negativ al duratei temporale a pachetului de electroni, primul dispozitiv STEAM a operat \u00een modul de comprimare. Durata pachetului de electroni pe acceleratorul liniar a fost optimizat\u0103 la un minimum de ~ 350 fs (l\u0103\u021bimea jum\u0103t\u0103\u021bii) prin ajusteaz\u0103 energia terahertz, care este aplicat\u0103 pe compresor \u0219i comut\u00e2nd acceleratorul liniar \u00een modul de scanare (<b>4b<\/b>).<\/p>\n<p><img decoding=\"async\" alt=\"Mic, dar puternic: acceleratorul liniar de particule miniatural care a stabilit un nou record\" src=\"\/wp-content\/uploads\/2019\/07\/f4c887b0cd58549da2bdc3a25ebab294.png\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<i>Imaginea nr. 4<\/i><\/p>\n<p>Durata minim\u0103 a pachetului a fost stabilit\u0103 \u00een conformitate cu durata impulsului UV al fotocatodului, care era de ~ 600 fs. De asemenea, distan\u021ba dintre compresor \u0219i benzi a jucat un rol important, limit\u00e2nd for\u021ba de comprimare \u00een func\u021bie de vitez\u0103. \u00cempreun\u0103, aceste m\u0103suri permit ob\u021binerea unei precizii de femtosecunde \u00een faza de introducere \u00een timpul acceler\u0103rii.<\/p>\n<p>\u00cen imaginea <b>4a<\/b> Se observ\u0103 c\u0103 dispersia energiei pachetului de electroni comprimat dup\u0103 accelerarea optimizat\u0103 \u00een acceleratorul liniar se reduce de ~ 4 ori comparativ cu cel necomprimat. Datorit\u0103 acceler\u0103rii, spectrul energetic al pachetului comprimat se deplaseaz\u0103 spre energii mai ridicate, spre deosebire de pachetul necomprimat. V\u00e2rful spectrului energetic dup\u0103 accelerare este de aproximativ 115 keV, iar coada de energie \u00eenalt\u0103 ajunge la aproximativ 125 keV.<\/p>\n<p>Aceste valori, conform declara\u021biilor modeste ale oamenilor de \u0219tiin\u021b\u0103, reprezint\u0103 un nou record de accelerare (p\u00e2n\u0103 la accelerare a fost de 70 keV) \u00een intervalul terahertz.<\/p>\n<p>Dar, pentru a reduce dispersia energiei (<i>4a<\/i>), este necesar s\u0103 se ating\u0103 un pachet \u0219i mai scurt. <\/p>\n<p><img decoding=\"async\" alt=\"Mic, dar puternic: acceleratorul liniar de particule miniatural care a stabilit un nou record\" src=\"\/wp-content\/uploads\/2019\/07\/7c53a1ca68dfbe52518d1dcd813ad6c9.png\" style=\"display:block;margin: 0 auto;\" \/><br \/>\n<i>Imaginea Nr. 5<\/i><\/p>\n<p>\u00cen cazul unui fascicul necomprimat, dependen\u021ba parabolic\u0103 a dimensiunii fasciculului de curent relev\u0103 emitan\u021ba transversal\u0103 \u00een direc\u021biile orizontal\u0103 \u0219i vertical\u0103: \u03b5x,n = 1.703 mm*mr \u0219i \u03b5y,n = 1.491 mm*mr (<b>5a<\/b>).<\/p>\n<p>Compresia, pe de alt\u0103 parte, a \u00eembun\u0103t\u0103\u021bit emitan\u021ba transversal\u0103 de 6 ori, p\u00e2n\u0103 la \u03b5x,n = 0.285 mm*mr (orizontal) \u0219i \u03b5y,n = 0.246 mm*mr (vertical).<\/p>\n<p>Merit\u0103 men\u021bionat c\u0103 gradul de reducere a emitan\u021bei este de aproximativ dou\u0103 ori mai mare dec\u00e2t gradul de reducere a duratei fasciculului, ceea ce este o m\u0103sur\u0103 a neliniarit\u0103\u021bii dinamicii interac\u021biunii \u00een timp, c\u00e2nd electronii sufer\u0103 o focalizare \u0219i defocalizare puternic\u0103 a c\u00e2mpului magnetic \u00een timpul accelera\u021biei (<b>5b<\/b> \u0219i <b>5c<\/b>).<\/p>\n<p>\u00cen imaginea <b>5b<\/b> se observ\u0103 c\u0103 electronii, introdu\u0219i la momentul optim, experimenteaz\u0103 \u00eentreaga semiperioad\u0103 a accelera\u021biei c\u00e2mpului electric. \u00cen schimb, electronii care sosesc \u00eenainte sau dup\u0103 momentul optim experimenteaz\u0103 o accelera\u021bie mai mic\u0103 \u0219i chiar o \u00eencetinire par\u021bial\u0103. Ace\u0219ti electroni ob\u021bin, \u00een rezultat, mai pu\u021bin\u0103 energie, grosso modo.<\/p>\n<p>O situa\u021bie similar\u0103 este observat\u0103 \u0219i \u00een cazul influen\u021bei c\u00e2mpului magnetic. Electronii introdu\u0219i la momentul optim sufer\u0103 o cantitate simetric\u0103 de c\u00e2mpuri magnetice pozitive \u0219i negative. Dac\u0103 introducerea electronilor a avut loc mai devreme dec\u00e2t momentul optim, au fost mai multe c\u00e2mpuri pozitive \u0219i mai pu\u021bine negative. \u00cen cazul introducerii electronilor mai t\u00e2rziu dec\u00e2t momentul optim \u2014 mai pu\u021bine c\u00e2mpuri pozitive \u0219i mai multe negative (<b>5c<\/b>). Aceste devia\u021bii conduc la faptul c\u0103 electronul poate devia la st\u00e2nga, la dreapta, \u00een sus sau \u00een jos, \u00een func\u021bie de pozi\u021bia sa fa\u021b\u0103 de ax\u0103, ceea ce duce la cre\u0219terea impulsului transversal, corespunz\u0103tor focaliz\u0103rii sau defocaliz\u0103rii fasciculului.<\/p>\n<p>Pentru o mai bun\u0103 \u00een\u021belegere a nuan\u021belor cercet\u0103rii, v\u0103 recomand s\u0103 consulta\u021bi <noindex><a rel=\"nofollow\" href=\"https:\/\/www.osapublishing.org\/optica\/fulltext.cfm?uri=optica-6-7-872&amp;id=415315\">raportul cercet\u0103torilor<\/a><\/noindex> \u0219i <noindex><a rel=\"nofollow\" href=\"https:\/\/osapublishing.figshare.com\/articles\/3990773_pdf\/8231024\">materiale suplimentare<\/a><\/noindex> la acesta.<\/p>\n<h3>Epilog<\/h3>\n<p>\nPentru a rezuma, performan\u021ba acceleratorului va cre\u0219te \u00een cazul reducerii duratei fasciculului de electroni. \u00cen aceast\u0103 lucrare, durata realizabil\u0103 a fasciculului a fost limitat\u0103 de geometria instala\u021biei. Dar, teoretic, durata fasciculului poate atinge \u0219i valori mai mici de 100 fs. <\/p>\n<p>De asemenea, oamenii de \u0219tiin\u021b\u0103 remarc\u0103 faptul c\u0103 calitatea fasciculului poate fi \u00eembun\u0103t\u0103\u021bit\u0103 ulterior prin reducerea \u00een\u0103l\u021bimii straturilor \u0219i cre\u0219terea num\u0103rului acestora. Totu\u0219i, aceast\u0103 metod\u0103 nu este lipsit\u0103 de probleme, \u00een special cre\u0219terea complexit\u0103\u021bii de produc\u021bie a dispozitivului.<\/p>\n<p>Aceast\u0103 lucrare reprezint\u0103 etapa ini\u021bial\u0103 a unei studii mai ample \u0219i detaliate asupra versiunii miniaturale a acceleratorului liniar. De\u0219i versiunea testat\u0103 deja arat\u0103 rezultate excelente, care pot fi cu adev\u0103rat considerate recorduri, mai este \u00eenc\u0103 mult de lucru. <\/p>\n<p>V\u0103 mul\u021bumesc pentru aten\u021bie, r\u0103m\u00e2ne\u021bi curio\u0219i \u0219i o s\u0103pt\u0103m\u00e2n\u0103 de lucru bun\u0103, b\u0103ie\u021bi! \ud83d\ude42<\/p>\n<p>V\u0103 mul\u021bumim c\u0103 r\u0103m\u00e2ne\u021bi cu noi. V\u0103 plac articolele noastre? Dori\u021bi s\u0103 vede\u021bi mai multe materiale interesante? Sus\u021bine\u021bi-ne f\u0103c\u00e2nd o comand\u0103 sau recomand\u00e2ndu-ne prietenilor. <b>30% reducere pentru utilizatorii Habr pentru un server entry-level unic, creat special pentru tine:<\/b> <noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/company\/ua-hosting\/blog\/347386\/\">Adev\u0103rul despre VPS (KVM) E5-2650 v4 (6 nuclee) 10GB DDR4 240GB SSD 1Gbps de la 20$ sau cum s\u0103 \u00eemp\u0103r\u021bim corect un server?<\/a><\/noindex> (sunt disponibile op\u021biuni cu RAID1 \u0219i RAID10, p\u00e2n\u0103 la 24 nuclee \u0219i p\u00e2n\u0103 la 40GB DDR4).<\/p>\n<p><b>Dell R730xd la jum\u0103tate de pre\u021b?<\/b> Numai la noi <b><noindex><a rel=\"nofollow\" href=\"https:\/\/ua-hosting.company\/serversnl\">2 x Intel TetraDeca-Core Xeon 2x E5-2697v3 2.6GHz 14C 64GB DDR4 4x960GB SSD 1Gbps 100 TB de la 199 $<\/a><\/noindex> \u00een Olanda! <b>Dell R420 \u2014 2x E5-2430 2.2Ghz 6C 128GB DDR3 2x960GB SSD 1Gbps 100TB \u2014 de la 99 $!<\/b><\/b> Citi\u021bi despre <noindex><a rel=\"nofollow\" href=\"https:\/\/habr.com\/company\/ua-hosting\/blog\/329618\/\">Cum s\u0103 construi\u021bi o infrastructur\u0103 de clas\u0103 enterprise folosind servere Dell R730xd E5-2650 v4 la pre\u021buri foarte mici de 9000 \u20ac?<\/a><\/noindex><br \/>\n<br \/>Sursa: <a content=\"nofollow\" rel=\"nofollow\" href=\"https:\/\/habr.com\/ru\/company\/ua-hosting\/blog\/460195\/\">habr.com<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"<p>\u041f\u0440\u0438\u0432\u044b\u0447\u043d\u044b\u0439 \u043d\u0430\u043c \u043f\u0440\u0438\u043d\u0446\u0438\u043f \u00ab\u0431\u043e\u043b\u044c\u0448\u0435 \u0437\u043d\u0430\u0447\u0438\u0442 \u043c\u043e\u0449\u043d\u0435\u0435\u00bb \u0443\u0436\u0435 \u0434\u0430\u0432\u043d\u043e \u0443\u0441\u0442\u043e\u044f\u043b\u0441\u044f \u0432 \u043c\u043d\u043e\u0433\u0438\u0445 \u043e\u0442\u0440\u0430\u0441\u043b\u044f\u0445 \u0436\u0438\u0437\u043d\u0438 \u043e\u0431\u0449\u0435\u0441\u0442\u0432\u0430, \u0432 \u0442\u043e\u043c \u0447\u0438\u0441\u043b\u0435 \u0432 \u043d\u0430\u0443\u043a\u0435 \u0438 \u0442\u0435\u0445\u043d\u043e\u043b\u043e\u0433\u0438\u044f\u0445. \u041e\u0434\u043d\u0430\u043a\u043e \u0432 \u0441\u043e\u0432\u0440\u0435\u043c\u0435\u043d\u043d\u044b\u0445 \u0440\u0435\u0430\u043b\u0438\u044f\u0445 \u0432\u0441\u0435 \u0447\u0430\u0449\u0435 \u0438 \u0447\u0430\u0449\u0435 \u0432\u0441\u0442\u0440\u0435\u0447\u0430\u0435\u0442\u0441\u044f \u043f\u0440\u0430\u043a\u0442\u0438\u0447\u0435\u0441\u043a\u0430\u044f \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u044f \u043f\u043e\u0433\u043e\u0432\u043e\u0440\u043a\u0438 \u00ab\u043c\u0430\u043b, \u0434\u0430 \u0443\u0434\u0430\u043b\u00bb. \u042d\u0442\u043e \u043f\u0440\u043e\u044f\u0432\u043b\u044f\u0435\u0442\u0441\u044f \u043a\u0430\u043a \u0432 \u043a\u043e\u043c\u043f\u044c\u044e\u0442\u0435\u0440\u0430\u0445, \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u0440\u0430\u043d\u0435\u0435 \u0437\u0430\u043d\u0438\u043c\u0430\u043b\u0438 \u0446\u0435\u043b\u0443\u044e \u043a\u043e\u043c\u043d\u0430\u0442\u0443, \u0430 \u0441\u0435\u0439\u0447\u0430\u0441 \u043f\u043e\u043c\u0435\u0449\u0430\u044e\u0442\u0441\u044f \u0432 \u043b\u0430\u0434\u043e\u0448\u043a\u0435 \u0440\u0435\u0431\u0435\u043d\u043a\u0430, \u0442\u0430\u043a \u0438 \u0432 [&hellip;]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":27115,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-36248","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 5.0.4 - aioseo.com -->\n\t<meta name=\"description\" content=\"\u041f\u0440\u0438\u0432\u044b\u0447\u043d\u044b\u0439.\" \/>\n\t<meta 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