<story><title>First images of collisions at 13 TeV</title><url>http://home.web.cern.ch/about/updates/2015/05/first-images-collisions-13-tev</url></story><parent_chain><item><author>iamthepieman</author><text>I followed the links to the CMS, Atlas and other detectors that the images appear to be from but couldn&amp;#x27;t find any information on what these images actually mean. By reading the layman&amp;#x27;s descriptions (which I most certainly am) I assume that the images show where along the &amp;quot;surface&amp;quot;, if there is such a thing, of the detector various particles were detected and the length of the bars show either how much energy the particle(s) have or the density of particles at that point.&lt;p&gt;Is there anywhere I can go to get a more detailed description of these without delving into academic papers that I have no hope of understanding?</text></item></parent_chain><comment><author>elwin</author><text>A detector is typically a series of concentric cylinders, with the beam pipe, where the collisions occur, running through the center. The inner layers are tracking chambers, which detect the paths of charged particles. This is what produces all the curved lines radiating from the center.&lt;p&gt;The outer layers are calorimeters, which catch particles and measure their kinetic energy. As you correctly assumed, these produce the bar plots. Often there will be one layer of calorimeters for photons and electrons, and a second for hadrons (protons, mesons, etc.)&lt;p&gt;This Wikipedia article is a good starting point: &lt;a href=&quot;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Hermetic_detector&quot; rel=&quot;nofollow&quot;&gt;https:&amp;#x2F;&amp;#x2F;en.wikipedia.org&amp;#x2F;wiki&amp;#x2F;Hermetic_detector&lt;/a&gt;</text></comment>
<story><title>First images of collisions at 13 TeV</title><url>http://home.web.cern.ch/about/updates/2015/05/first-images-collisions-13-tev</url></story><parent_chain><item><author>iamthepieman</author><text>I followed the links to the CMS, Atlas and other detectors that the images appear to be from but couldn&amp;#x27;t find any information on what these images actually mean. By reading the layman&amp;#x27;s descriptions (which I most certainly am) I assume that the images show where along the &amp;quot;surface&amp;quot;, if there is such a thing, of the detector various particles were detected and the length of the bars show either how much energy the particle(s) have or the density of particles at that point.&lt;p&gt;Is there anywhere I can go to get a more detailed description of these without delving into academic papers that I have no hope of understanding?</text></item></parent_chain><comment><author>kordless</author><text>The amount of data that comes out of the different detectors on the LHC is staggering. It takes a fair amount of post processing to get meaningful results from collisions, and there can be millions of collisions in a run. There&amp;#x27;s some more information about how they process these results on the LHC computing grid page: &lt;a href=&quot;http:&amp;#x2F;&amp;#x2F;wlcg-public.web.cern.ch&amp;#x2F;&quot; rel=&quot;nofollow&quot;&gt;http:&amp;#x2F;&amp;#x2F;wlcg-public.web.cern.ch&amp;#x2F;&lt;/a&gt;.</text></comment>