—nmr实验技术基础(1nmr仪器)

《—nmr实验技术基础(1nmr仪器)》由会员上传分享，免费在线阅读，更多相关内容在应用文档-天天文库。

1、第三章NMR实验技术基础1NMR仪器如图，现代超导核磁谱仪的主要组成部分包括：1.超导磁体Magnet包括FieldLock，ShimCoils2.探头Probe内有RFCoils，GradientCoils3.脉冲编程器及射频放大器4.接收器5.数据采集及处理计算机Atthetopoftheschematicrepresentation,youwillfindthesuperconductingmagnetoftheNMRspectrometer.ThemagnetproducestheBofieldnecessaryfortheNMR

2、experiments.ImmediatelywithintheboreofthemagnetaretheshimcoilsforhomogenizingtheBofield.Withintheshimcoilsistheprobe.TheprobecontainstheRFcoilsforproducingtheB1magneticfieldnecessarytorotatethespins.TheRFcoilalsodetectsthesignalfromthespinswithinthesample.Thesampleisposit

3、ionedwithintheRFcoiloftheprobe.Someprobesalsocontainasetofgradientcoils.ThesecoilsproduceagradientinBoalongtheX,Y,orZaxis.Gradientcoilsareusedforforgradientenhancedspectroscopy,diffusion,andNMRmicroscopyexperiments.Theheartofthespectrometeristhecomputer.Itcontrolsallofthe

4、componentsofthespectrometer.TheRFcomponentsundercontrolofthecomputeraretheRFfrequencysourceandpulseprogrammer.Thesourceproducesasinewaveofthedesiredfrequency.Thepulseprogrammersetsthewidth,andinsomecasestheshape,oftheRFpulses.TheRFamplifierincreasesthepulsespowerfrommilli

5、WattstotensorhundredsofWatts.Thecomputeralsocontrolsthegradientpulseprogrammerwhichsetstheshapeandamplitudeofgradientfields.Thegradientamplifierincreasesthepowerofthegradientpulsestoalevelsufficienttodrivethegradientcoils.Theoperatorofthespectrometergivesinputtothecompute

6、rthroughaconsoleterminalwithamouseandkeyboard.Somespectrometersalsohaveaseparatesmallinterfaceforcarryingoutsomeofthemoreroutineproceduresonthespectrometer.Apulsesequenceisselectedandcustomizedfromtheconsoleterminal.Theoperatorcanseespectraonavideodisplaylocatedontheconso

7、leandcanmakehardcopiesofspectrausingaprinter.1.超导磁体MagnetMagnet主要要求：a高磁场强度,分辨率与B0成正比，而灵敏度与成正比，故750MHz较600MHz的分辨率提高25%,而灵敏度提高40%b高均匀性,目前可达10-9c高稳定性TheNMRmagnetisoneofthemostexpensivecomponentsofthenuclearmagneticresonancespectrometersystem.Mostmagnetsareofthesuperconductin

8、gtype.Asuperconductingmagnethasanelectromagnetmadeofsuperconductingwire.Superconductingwirehasar