{"id":3692,"date":"2023-03-13T08:09:41","date_gmt":"2023-03-13T15:09:41","guid":{"rendered":"https:\/\/www.rbdinstruments.com\/blog\/?p=3692"},"modified":"2023-03-13T08:30:29","modified_gmt":"2023-03-13T15:30:29","slug":"xps-analyzer-control-non-linearity-problem","status":"publish","type":"post","link":"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/","title":{"rendered":"XPS analyzer control non-linearity problem"},"content":{"rendered":"\n<p>The 80-360 and 80-365\/366 analyzer controls provide all the voltages to the 10-360 spherical capacitor analyzer that is used on many PHI (Physical Electronics) XPS systems.<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?ssl=1\"><img data-attachment-id=\"3697\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/80-365-boards\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?fit=2000%2C1500&amp;ssl=1\" data-orig-size=\"2000,1500\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"80-365-boards\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?fit=300%2C225&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?fit=584%2C438&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"438\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?resize=584%2C438&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards-1024x768.jpg\" alt=\"\" class=\"lazy wp-image-3697\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=1024%2C768&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=300%2C225&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=768%2C576&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=1536%2C1152&amp;ssl=1 1536w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=400%2C300&amp;ssl=1 400w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?w=2000&amp;ssl=1 2000w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?w=1168&amp;ssl=1 1168w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?w=1752&amp;ssl=1 1752w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><noscript><img data-attachment-id=\"3697\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/80-365-boards\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?fit=2000%2C1500&amp;ssl=1\" data-orig-size=\"2000,1500\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"80-365-boards\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?fit=300%2C225&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?fit=584%2C438&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"438\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=584%2C438&#038;ssl=1\" alt=\"\" class=\"wp-image-3697\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=1024%2C768&amp;ssl=1 1024w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=300%2C225&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=768%2C576&amp;ssl=1 768w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=1536%2C1152&amp;ssl=1 1536w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?resize=400%2C300&amp;ssl=1 400w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?w=2000&amp;ssl=1 2000w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?w=1168&amp;ssl=1 1168w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/80-365-boards.jpg?w=1752&amp;ssl=1 1752w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><\/noscript><\/a><figcaption>80-365 boards  Retard board is third from left<\/figcaption><\/figure>\n\n\n\n<p>The retard voltage is used to slow down electrons and is essentially the sweep voltage.&nbsp; In conjunction with the pass energy supply, the retard voltage controls the energy of the electrons that are being passed through the analyzer and into the electron multiplier and counting circuitry.<\/p>\n\n\n\n<p>I recently had an interesting problem with a retard board on an 80-360 analyzer controller.&nbsp; The issue was that the retard board output voltage was not linear.&nbsp;&nbsp; Part of the calibration procedure for the retard board is to test the voltage at 11 specific voltages ranging from 253.6 volts to 1253.6 volts in increments of 100 volts.&nbsp; This is a convenient way to confirm that the retard supply is linear.&nbsp; The table below shows the hex commands that are used to set the voltages and the expected results.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?ssl=1\"><img data-attachment-id=\"3694\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/expected-retard-votlage-measurements\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?fit=846%2C847&amp;ssl=1\" data-orig-size=\"846,847\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Expected-Retard-Votlage-Measurements\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?fit=584%2C585&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"585\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?resize=584%2C585&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg\" alt=\"\" class=\"lazy wp-image-3694\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?w=846&amp;ssl=1 846w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?resize=768%2C769&amp;ssl=1 768w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><noscript><img data-attachment-id=\"3694\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/expected-retard-votlage-measurements\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?fit=846%2C847&amp;ssl=1\" data-orig-size=\"846,847\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"Expected-Retard-Votlage-Measurements\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?fit=584%2C585&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"585\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?resize=584%2C585&#038;ssl=1\" alt=\"\" class=\"wp-image-3694\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?w=846&amp;ssl=1 846w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Expected-Retard-Votlage-Measurements.jpg?resize=768%2C769&amp;ssl=1 768w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p>In this particular case, the output voltages were close to correct at some points, but way off at other points as shown below. This non-linearity would present itself as inconsistent peak widths in the data as a function of kinetic energy.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?ssl=1\"><img data-attachment-id=\"3695\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/actual-retard-votlage-measurements\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?fit=846%2C847&amp;ssl=1\" data-orig-size=\"846,847\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Actual-Retard-Votlage-Measurements\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?fit=584%2C585&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"585\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?resize=584%2C585&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg\" alt=\"\" class=\"lazy wp-image-3695\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?w=846&amp;ssl=1 846w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?resize=768%2C769&amp;ssl=1 768w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><noscript><img data-attachment-id=\"3695\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/actual-retard-votlage-measurements\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?fit=846%2C847&amp;ssl=1\" data-orig-size=\"846,847\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;1&quot;}\" data-image-title=\"Actual-Retard-Votlage-Measurements\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?fit=300%2C300&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?fit=584%2C585&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"584\" height=\"585\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?resize=584%2C585&#038;ssl=1\" alt=\"\" class=\"wp-image-3695\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?w=846&amp;ssl=1 846w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/Actual-Retard-Votlage-Measurements.jpg?resize=768%2C769&amp;ssl=1 768w\" sizes=\"(max-width: 584px) 100vw, 584px\" data-recalc-dims=\"1\" \/><\/noscript><\/a><\/figure>\n\n\n\n<p>These results at first glance look like a bit problem.&nbsp; That is, the digital to analog convertor (DAC) voltages are likely off.&nbsp; The DAC used in the retard board circuit is a 16 bit DAC and the output voltages should follow the voltages listed&nbsp; below.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><a href=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?ssl=1\"><img data-attachment-id=\"3696\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/dac-voltages\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?fit=501%2C487&amp;ssl=1\" data-orig-size=\"501,487\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"DAC-voltages\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?fit=300%2C292&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?fit=501%2C487&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"501\" height=\"487\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/plugins\/jquery-image-lazy-loading\/images\/grey.gif?resize=501%2C487&#038;ssl=1\" data-original=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg\" alt=\"\" class=\"lazy wp-image-3696\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?w=501&amp;ssl=1 501w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?resize=300%2C292&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?resize=309%2C300&amp;ssl=1 309w\" sizes=\"(max-width: 501px) 100vw, 501px\" data-recalc-dims=\"1\" \/><noscript><img data-attachment-id=\"3696\" data-permalink=\"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/dac-voltages\/\" data-orig-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?fit=501%2C487&amp;ssl=1\" data-orig-size=\"501,487\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"DAC-voltages\" data-image-description=\"\" data-image-caption=\"\" data-medium-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?fit=300%2C292&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?fit=501%2C487&amp;ssl=1\" decoding=\"async\" loading=\"lazy\" width=\"501\" height=\"487\" src=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?resize=501%2C487&#038;ssl=1\" alt=\"\" class=\"wp-image-3696\" srcset=\"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?w=501&amp;ssl=1 501w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?resize=300%2C292&amp;ssl=1 300w, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/DAC-voltages.jpg?resize=309%2C300&amp;ssl=1 309w\" sizes=\"(max-width: 501px) 100vw, 501px\" data-recalc-dims=\"1\" \/><\/noscript><\/a><figcaption>DAC Voltages<\/figcaption><\/figure>\n\n\n\n<p>However, the DAC voltages were fine.&nbsp; The retard voltage circuit comprises the DAC which drives a precision operational amplifier that in turn drives a high voltage switching supply.&nbsp; Some precision high voltage resistors are&nbsp; used to provide feedback.&nbsp; The next most likely component that might be non-linear was the <a href=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/OP07.pdf\" data-type=\"attachment\" data-id=\"3700\">OP07<\/a> ultra-low offset operational amplifier (op amp).&nbsp; The OP07 was replaced but did not solve the problem.<\/p>\n\n\n\n<p>The next most likely cause of the non-linearity problem was the feedback resistors. &nbsp;There is a total of 5 of these <a href=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/SX3730-5W-resistor.pdf\" data-type=\"attachment\" data-id=\"3699\">SX3730 5 watt wire wound high precision axial resistors<\/a> in series.&nbsp; To accurately measure those resistors, you need to lift one end off the circuit board.&nbsp; Using my Fluke multimeter, I tested the resistance of each resistor and they all checked out as OK.&nbsp; Ideally you will see very close to 1.0 megohms, but it might be off by .05 megohms.&nbsp;When a resistor is bad it will be open or be off by as much as .5 megohms. So, it seemed that the feedback resistors were OK as well.<\/p>\n\n\n\n<p>That left not much in the circuit other than a few potentiometers.&nbsp;After spending some more time retesting all the components, I came to the conclusion that it had to be one of those feedback resistors.&nbsp;<\/p>\n\n\n\n<p>To test that theory I removed all 5 of the <a href=\"https:\/\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/SX3730.jpg\" data-type=\"attachment\" data-id=\"3703\">SX3730<\/a> 1 megohm feedback resistors and replaced them with a single 5 meg ohm resistor.&nbsp; And that worked!&nbsp;&nbsp; So now I knew for sure that one of those 5 feedback resistors was the problem.&nbsp; I measured the resistance of each resistor, and they looked OK.&nbsp; But then I realized that the non-linearity is a function of the voltage applied to the resistor. At some voltages the resistance was OK, but at other voltages the resistance was off.&nbsp;<\/p>\n\n\n\n<p>I then decided to measure the resistance value again using a megohmmeter.&nbsp; The model that I used was a Protek DI-2000M.&nbsp; This megohmmeter (also called an insulation tester) puts 500 V across the resistor when measuring the resistance. I hoped that by putting 500V across the resistor that I would be able to see a greater difference in the resistance values. And that worked out as expected.&nbsp; One of the resistors showed only 965 Kohms with the megohmmeter and 995 Kohms with the Fluke.&nbsp;I replaced that resistor and the calibration was perfect.&nbsp; \ud83d\ude0a<\/p>\n\n\n\n<p>In hindsight, duh. Since the gain of the circuit was changing as a function of the non-linearity of one resistor, the lesson is that when checking the resistance of suspected non-linear resistors, always use a megohmmeter since that will put much more voltage across the resistor than what a normal DVM will put out. Better yet, if possible, use the highest voltage that the resistor is rated for.<\/p>\n\n\n\n<p>If your 80-360 or 80-365\/366 analyzer control is not functioning properly and you need some help, please contact RBD Instruments for assistance as needed.<\/p>\n\n\n\n<p><\/p>\n","protected":false},"excerpt":{"rendered":"<p>80-360 analyzer control retard voltage non-linearity issue and solution <a href=\"https:\/\/www.rbdinstruments.com\/blog\/xps-analyzer-control-non-linearity-problem\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":3703,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","footnotes":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false}}},"categories":[162],"tags":[408,376,410,409],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2023\/03\/SX3730.jpg?fit=756%2C756&ssl=1","jetpack_shortlink":"https:\/\/wp.me\/p2DEXo-Xy","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"jetpack-related-posts":[{"id":1184,"url":"https:\/\/www.rbdinstruments.com\/blog\/xps-aes-peak-linearity-adjustments\/","url_meta":{"origin":3692,"position":0},"title":"XPS and AES peak linearity adjustments","author":"Randy","date":"July 21, 2014","format":false,"excerpt":"This post is a compilation of some calibration tech tips that I have written over the years. The procedures listed below explain how to calibrate the following systems and units: 5600 and 5400 XPS systems, Double pass CMA XPS analyzers Scanning Auger system, Auger analyzers WARNING: Some of these procedures\u2026","rel":"","context":"In &quot;Operation and Calibration Procedures&quot;","block_context":{"text":"Operation and Calibration Procedures","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/operation-and-calibration-procedures\/"},"img":{"alt_text":"xps-copper-gold-peaks","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2014\/07\/xps-copper-gold-peaks.jpg?fit=717%2C471&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2014\/07\/xps-copper-gold-peaks.jpg?fit=717%2C471&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2014\/07\/xps-copper-gold-peaks.jpg?fit=717%2C471&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":1420,"url":"https:\/\/www.rbdinstruments.com\/blog\/5600-xps-analyzer-voltages\/","url_meta":{"origin":3692,"position":1},"title":"5600 XPS analyzer voltages","author":"Randy","date":"April 22, 2015","format":false,"excerpt":"One of the more common questions that we get when a PHI 5500 or 5600 XPS system loses the ability to collect data, is -\u00a0 \"how can we test the analyzer voltages?\"\u00a0\u00a0 This post will explain the procedure in detail. First though, the disclaimers - #1 This procedure involves measuring\u2026","rel":"","context":"In &quot;General Optics and Vacuum&quot;","block_context":{"text":"General Optics and Vacuum","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/general-optics-and-vacuum\/"},"img":{"alt_text":"5600 SCA filter box","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2015\/04\/5600-SCA-filter-box.jpg?fit=972%2C648&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2015\/04\/5600-SCA-filter-box.jpg?fit=972%2C648&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2015\/04\/5600-SCA-filter-box.jpg?fit=972%2C648&ssl=1&resize=700%2C400 2x"},"classes":[]},{"id":3425,"url":"https:\/\/www.rbdinstruments.com\/blog\/80-365-analyzer-control-notes\/","url_meta":{"origin":3692,"position":2},"title":"80-365 analyzer control notes","author":"Randy","date":"October 18, 2021","format":false,"excerpt":"Notes related to calibrating and troubleshooting the 80-365 analyzer controller used on older PHI XPS X-ray photoelectron spectrometers.","rel":"","context":"In &quot;Operation and Calibration Procedures&quot;","block_context":{"text":"Operation and Calibration Procedures","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/operation-and-calibration-procedures\/"},"img":{"alt_text":"80-365 lens board","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2021\/10\/80365-lens-board.jpg?fit=1200%2C1200&ssl=1&resize=350%2C200","width":350,"height":200,"srcset":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2021\/10\/80365-lens-board.jpg?fit=1200%2C1200&ssl=1&resize=350%2C200 1x, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2021\/10\/80365-lens-board.jpg?fit=1200%2C1200&ssl=1&resize=700%2C400 2x, https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2021\/10\/80365-lens-board.jpg?fit=1200%2C1200&ssl=1&resize=1050%2C600 3x"},"classes":[]},{"id":345,"url":"https:\/\/www.rbdinstruments.com\/blog\/ion-beam-induced-low-energy-electrons\/","url_meta":{"origin":3692,"position":3},"title":"Ion Beam Induced Low Energy Electrons","author":"Randy","date":"February 6, 2013","format":false,"excerpt":"For the purpose of checking the performance of a surface analysis spectrometer such as a cylindrical mirror analyzer (CMA) or spherical capacitive analyzer (SCA), looking at an ion induced low energy electron peak can be extremely helpful. The peak typically occurs at about 20 to 50 eV and the size\u2026","rel":"","context":"In &quot;Operation and Calibration Procedures&quot;","block_context":{"text":"Operation and Calibration Procedures","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/operation-and-calibration-procedures\/"},"img":{"alt_text":"ion gun noise","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2013\/02\/Ion-gun-noise.png?resize=350%2C200&ssl=1","width":350,"height":200},"classes":[]},{"id":568,"url":"https:\/\/www.rbdinstruments.com\/blog\/electron-multipliers-used-in-phi-aes-and-xps-analyzers\/","url_meta":{"origin":3692,"position":4},"title":"Electron multipliers used in PHI AES and XPS analyzers","author":"Randy","date":"May 17, 2013","format":false,"excerpt":"The Physical Electronics AES cylindrical mirror (CMA), double-pass ESCA (XPS) and single channel SCA hemisphere analyzers use variations of the Channeltron\u00ae (registered trade mark of Photonis \u2013 Burle \u2013 Galileo) type of electron multiplier. The function of the electron multiplier is to increase the number of electrons that the analyzer\u2026","rel":"","context":"In &quot;General Optics and Vacuum&quot;","block_context":{"text":"General Optics and Vacuum","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/general-optics-and-vacuum\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2013\/05\/channeltron-electron-multiplier.jpg?fit=203%2C267&ssl=1&resize=350%2C200","width":350,"height":200},"classes":[]},{"id":4040,"url":"https:\/\/www.rbdinstruments.com\/blog\/20-805-or-11-500a-analyzer-control-sweep-voltage-test\/","url_meta":{"origin":3692,"position":5},"title":"20-805 or 11-500A analyzer control sweep voltage test","author":"Randy","date":"June 26, 2024","format":false,"excerpt":"Older PHI cylindrical mirror analyzers (CMA) uses two cylinders to focus electrons of a particular energy into an aperture for amplification via an electron multiplier. For AES, the inner cylinder is at ground potential and the outer cylinder has a voltage applied to it (sweep voltage) that deflects the electrons\u2026","rel":"","context":"In &quot;General Optics and Vacuum&quot;","block_context":{"text":"General Optics and Vacuum","link":"https:\/\/www.rbdinstruments.com\/blog\/category\/general-optics-and-vacuum\/"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/www.rbdinstruments.com\/blog\/wp-content\/uploads\/2024\/06\/Analyzer-pins.png?fit=422%2C279&ssl=1&resize=350%2C200","width":350,"height":200},"classes":[]}],"_links":{"self":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts\/3692"}],"collection":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/comments?post=3692"}],"version-history":[{"count":2,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts\/3692\/revisions"}],"predecessor-version":[{"id":3710,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/posts\/3692\/revisions\/3710"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/media\/3703"}],"wp:attachment":[{"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/media?parent=3692"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/categories?post=3692"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.rbdinstruments.com\/blog\/wp-json\/wp\/v2\/tags?post=3692"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}