Daim ntawv thov ntawm Transmission Electron Microscopy
daim ntawv thov
Vim qhov nce siab thiab lub sij hawm teb luv luv ntawm lub raj photomultiplier, thiab vim tias nws cov zis tam sim no yog proportional rau tus naj npawb ntawm cov xwm txheej photons, nws yog dav siv hauv astrophotometric thiab astrospectrophotometry. Nws qhov zoo yog: qhov ntsuas qhov tseeb siab, tuaj yeem ntsuas lub cev tsis zoo ntawm lub cev, thiab tuaj yeem ntsuas qhov hloov pauv sai ntawm lub cev lub cev luminosity. Nyob rau hauv astronomical photometry, lub multiplier raj ntawm antimony cesium photocathode yog dav siv, xws li RCA1p21. Qhov siab tshaj plaws quantum efficiency ntawm no photomultiplier raj yog nyob ib ncig ntawm 4200 Angstroms, uas yog hais txog 20 feem pua. Kuj tseem muaj lub raj photomultiplier nrog ob lub alkali photocathode, xws li GDB-53. Nws lub teeb liab-rau-lub suab sib piv yog qhov kev txiav txim siab loj dua li ntawm RCA1p21, thiab nws cov undercurrent tsawg heev. Txhawm rau soj ntsuam thaj tsam ze-infrared, cov raj photomultiplier nrog ntau-alkali photocathode thiab gallium arsenide cathode feem ntau siv, thiab quantum efficiency ntawm tom kawg tuaj yeem ncav cuag li 50 feem pua.
Ordinary photomultiplier hlab tsuas tuaj yeem ntsuas ib qho ntawm cov ntaub ntawv ntawm ib lub sijhawm, uas yog, tus naj npawb ntawm cov channel yog 1. matrix. Txij li cov xov tooj ntawm cov channel raug txwv los ntawm cov hlau nyias nyias ntawm qhov kawg ntawm cov anode, tsuas yog ntau pua ntawm cov channel tuaj yeem ua tiav.
kev ua haujlwm yam ntxwv
1. Kev ruaj ntseg
Kev ruaj ntseg ntawm lub photomultiplier raj yog txiav txim siab los ntawm ntau yam xws li cov yam ntxwv ntawm cov cuab yeej nws tus kheej, kev ua haujlwm thiab ib puag ncig. Muaj ntau qhov xwm txheej uas qhov tso zis ntawm lub raj tsis ruaj khov thaum lub sijhawm ua haujlwm, feem ntau suav nrog:
ib. Dhia instability tshwm sim los ntawm tsis zoo vuam ntawm electrodes nyob rau hauv lub raj, xoob qauv, tsis zoo sib cuag ntawm cathode shrapnel, ntswj tawm ntawm electrodes, flashover, thiab lwm yam, thiab lub teeb liab yog dheev loj thiab me.
b. Txuas ntxiv thiab qaug zog instability tshwm sim los ntawm ntau dhau anode tso zis tam sim no.
c. Qhov cuam tshuam ntawm Environmental Conditions ntawm Stability. Raws li ambient kub nce, qhov rhiab heev ntawm lub raj txo.
d. Ib puag ncig huab cua ua rau cov pa tawm ntawm cov pins, ua rau tam sim no tsaus nti kom nce thiab tsis ruaj khov.
e. Environmental electromagnetic teb cuam tshuam ua rau kev ua haujlwm tsis ruaj khov.
2. Txwv kev ua haujlwm voltage
Qhov kawg ua hauj lwm voltage yog hais txog lub sab sauv txwv ntawm voltage uas lub raj tso cai rau thov. Tshaj qhov voltage no, lub raj yuav tawm los yog tawg.
