{"id":2537,"date":"2021-08-27T12:32:49","date_gmt":"2021-08-27T19:32:49","guid":{"rendered":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/?p=2537"},"modified":"2021-08-27T12:32:49","modified_gmt":"2021-08-27T19:32:49","slug":"update-av500-shim-system-tamed-mostly","status":"publish","type":"post","link":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/2021\/08\/update-av500-shim-system-tamed-mostly\/","title":{"rendered":"UPDATE : AV500 &#8211; SHIM SYSTEM TAMED &#8211; MOSTLY"},"content":{"rendered":"<p>Dear Users<\/p>\n<p>I mentioned last week that a couple of hardware related issues need addressing and this is an update about the first and foremost of them :\u00a0 getting consistent results from Topshim method of shimming for all Lock Solvents.<\/p>\n<ul>\n<li>\u00a0 The root cause for the sporadic failure of Topshim, especially for weak lock signals like CDCl3 has been traced to a poor 2H NMR resonance signal that is used under the hood for both locking and shimming.\u00a0\u00a0 I have applied an optimized parameter set to mitigate this so that Topshim should work now with all 100% deuterated solvents such as CDCl3.<\/li>\n<li>There is still this question of why the 2H resonance signal is weak to begin with. This is a hardware related issue which is being looked into.\u00a0 The remedy applied will be seamless and you won&#8217;t notice much other than my loitering near the spectrometer a few times in the coming days.<\/li>\n<\/ul>\n<h2>IMPORTANCE OF TOUCHING UP THE X AND Y SHIMS :<\/h2>\n<p><strong>Topshim will ONLY optimize the Z-axis shims !<\/strong> To get a quick and best final spectrum, it is for us to optimize the so called &#8216;transverse&#8217; or XY plane shims.\u00a0 There are <strong>just two <\/strong>shims for you to take care of : <strong>X and Y.\u00a0\u00a0\u00a0 <\/strong>Here is what you do :<\/p>\n<ul>\n<li>After Topshim completes its job,\u00a0 type &#8216;<em><strong>bsmsdisp<\/strong><\/em><em>&#8216;\u00a0 <\/em>on the command line.\u00a0 You will get a graphical window which has buttons like the one shown here : <a href=\"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/06\/Screenshot-from-2021-06-23-15-17-26.png\"><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-full wp-image-2480\" src=\"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/06\/Screenshot-from-2021-06-23-15-17-26.png\" alt=\"\" width=\"463\" height=\"606\" srcset=\"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/06\/Screenshot-from-2021-06-23-15-17-26.png 463w, https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/06\/Screenshot-from-2021-06-23-15-17-26-229x300.png 229w\" sizes=\"(max-width: 463px) 100vw, 463px\" \/><\/a><\/li>\n<li>You click on the <strong> X button <\/strong>to select it and then use either the <strong>Step+ <\/strong>or <strong>Step- <\/strong>buttons to increase the lock level monotonically,\u00a0 as far as you can go.<\/li>\n<li>Repeat the operation for <strong>Y button.\u00a0\u00a0 <\/strong><\/li>\n<li>That&#8217;s it !\u00a0 You have touched up the <strong>X <\/strong>and <strong>Y <\/strong>shims.<\/li>\n<\/ul>\n<p>I will leave you with the following comparative spectrum recorded on AV500 to give you an idea, how much of a difference this simple step above will make.\u00a0\u00a0 In the spectrum shown below,\u00a0 the <strong>GREEN<\/strong> trace is after just Topshim completion.\u00a0 The <strong>RED <\/strong>trace is recorded with the sample spun at 20 Hz.\u00a0 But the <strong>BLUE<\/strong> trace is recorded on the same sample, after touching up your\u00a0<strong>X <\/strong>and\u00a0<strong>Y <\/strong>shims and <strong>without any spinning ! <\/strong>You can see that the <strong>BLUE trace is almost as good as a sample spun <\/strong>to get the best homogeneity.<\/p>\n<p><a href=\"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/08\/Effect_of_XY_touchup.png\"><img decoding=\"async\" loading=\"lazy\" class=\"alignnone size-large wp-image-2538\" src=\"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/08\/Effect_of_XY_touchup-1024x513.png\" alt=\"\" width=\"624\" height=\"313\" srcset=\"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/08\/Effect_of_XY_touchup-1024x513.png 1024w, https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/08\/Effect_of_XY_touchup-300x150.png 300w, https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/08\/Effect_of_XY_touchup-768x385.png 768w, https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-content\/uploads\/2021\/08\/Effect_of_XY_touchup.png 1394w\" sizes=\"(max-width: 624px) 100vw, 624px\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<p>NMR Facility Manager<\/p>\n<p>8\/27\/21<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Dear Users I mentioned last week that a couple of hardware related issues need addressing and this is an update about the first and foremost of them :\u00a0 getting consistent results from Topshim method of shimming for all Lock Solvents. \u00a0 The root cause for the sporadic failure of Topshim, especially for weak lock signals [&hellip;]<\/p>\n","protected":false},"author":19,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[11,10,9,7],"tags":[],"_links":{"self":[{"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/posts\/2537"}],"collection":[{"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/users\/19"}],"replies":[{"embeddable":true,"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/comments?post=2537"}],"version-history":[{"count":1,"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/posts\/2537\/revisions"}],"predecessor-version":[{"id":2539,"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/posts\/2537\/revisions\/2539"}],"wp:attachment":[{"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/media?parent=2537"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/categories?post=2537"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/depts.washington.edu\/chemwp\/chemwpnmr\/wp-json\/wp\/v2\/tags?post=2537"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}