{"id":481,"date":"2014-02-02T17:28:02","date_gmt":"2014-02-02T16:28:02","guid":{"rendered":"http:\/\/gifna.unizar.es\/cast\/?p=481"},"modified":"2015-09-13T08:25:26","modified_gmt":"2015-09-13T07:25:26","slug":"summary-of-micromegas-detectors-in-2013","status":"publish","type":"post","link":"https:\/\/gifna.unizar.es\/iaxo\/?p=481","title":{"rendered":"CAST Micromegas detectors: progress in 2013"},"content":{"rendered":"<p style=\"text-align: justify;\">During 2013, there were many upgrades in the Micromegas detectors of CAST, concerning muon veto system for the Sunset detectors, new readout electronics &amp; DAQ, and a new detector design carefully conceived for low background. The performance of the Sunset Micromegas detectors was very good during all the 2013 CAST data taking, achieving the lowest background levels ever of the experiment. Although many problems arose in the Sunrise Micromegas installation, we finally managed to make it work. During the installation we learned many new strategies in which we are currently working for the 2014 upgrade.<\/p>\n<p style=\"text-align: justify;\">\u00a0For a more detailed description of CAST Micromegas activities in 2013 continue reading!<\/p>\n<p><span style=\"font-size: x-large;\"><strong>1. \u00a0 2013 UPGRADES<\/strong><\/span><\/p>\n<ul>\n<li><span style=\"font-size: large;\"><strong>New muon veto on Sunset Micromegas<\/strong><\/span>\n<ul>\n<ul>\n<li style=\"text-align: justify;\">Increased the coverage from 44% (2012) to 95% (2013).<\/li>\n<li style=\"text-align: justify;\">The background reduction increases from 25% (2012) to 40% (2013).<\/li>\n<li style=\"text-align: justify;\">Vacuum system modified to facilitate the veto assembly &amp; to fit the new electronics.<\/li>\n<\/ul>\n<\/ul>\n<\/li>\n<\/ul>\n<ul>\n<li><span style=\"font-size: large;\"><strong>AFTER-chip based electronics + new DAQ (Sunset &amp; Sunrise Micromegas)<\/strong><\/span>\n<ul>\n<ul>\n<li>The Gassiplex-based readout\u00a0was substituted by theAFTER based\u00a0electronics (T2K).<\/li>\n<li>Now a pulse\/strip is recorded.<\/li>\n<li>More handles for better\u00a0background discrimination.<\/li>\n<li>Automatic data-taking for Sunset and Sunrise.\u00a0Possibility for an online check.<\/li>\n<\/ul>\n<\/ul>\n<\/li>\n<\/ul>\n<ul>\n<li><span style=\"font-size: large;\"><strong>Uprade of the Sunrise Micromegas<\/strong><\/span>\n<ul>\n<ul>\n<li><strong>Chamber: <\/strong>\n<ul>\n<li>radiopurity of materials (chamber out of Cu), also serves as inner shielding.<\/li>\n<li>Field shaper: electric drift field configuration improvement.<\/li>\n<li>Front End Electronics: new connectors and cards.<\/li>\n<li>Inner teflon layer to minimize 8 keV Cu-peak.<\/li>\n<\/ul>\n<\/li>\n<li><strong>New Detector:<\/strong>\n<ul>\n<li>Design idea: Incorporate the HV lines in the detector layout in order to<br \/>\nsimplify the connections.<\/li>\n<li>Three detectors delivered and tested. Very good performance in CAST Lab.<\/li>\n<\/ul>\n<\/li>\n<li><span style=\"color: #000000;\"><b>Shielding:\u00a0<\/b><\/span>\n<ul>\n<li>Platform for the shielding installed.<\/li>\n<li>Improvement in copper and lead shielding despite restrictions in dimensions.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/ul>\n<\/li>\n<\/ul>\n<figure id=\"attachment_491\" aria-describedby=\"caption-attachment-491\" style=\"width: 540px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/gifna.unizar.es\/cast\/wp-content\/uploads\/2014\/02\/vetosYdetector.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-491\" alt=\"New veto system design for the Sunset Micromegas (left) and new Sunrise detector schematics (right)\" src=\"http:\/\/gifna.unizar.es\/cast\/wp-content\/uploads\/2014\/02\/vetosYdetector.jpg\" width=\"540\" height=\"175\" srcset=\"https:\/\/gifna.unizar.es\/iaxo\/wp-content\/uploads\/2014\/02\/vetosYdetector.jpg 540w, https:\/\/gifna.unizar.es\/iaxo\/wp-content\/uploads\/2014\/02\/vetosYdetector-300x97.jpg 300w\" sizes=\"auto, (max-width: 540px) 100vw, 540px\" \/><\/a><figcaption id=\"caption-attachment-491\" class=\"wp-caption-text\">New veto system design for the Sunset Micromegas (left) and new Sunrise detector schematics (right)<\/figcaption><\/figure>\n<p><span style=\"font-size: x-large;\"><strong>2. \u00a0 SUNRISE MICROEMGAS INSTALLATION<\/strong><\/span><\/p>\n<p>Here, \u00a0we summarize the problems we faced during the installation of the Sunrise Micromegas, and the solutions\/changes we plan for the 2014 installation. Although we only managed to take one week of data \u00a0with the Sunrise Micromegas in 2013 (see below:\u00a0<strong>2013 DATA TAKING <\/strong><strong>)<\/strong>, the experience was very useful for gaining experience and comissioning \u00a0all the new systems installed (electronics, DAQ, shielding, windows, etc.).<\/p>\n<ul>\n<li><span style=\"font-size: large;\"><strong>SRMM Problems<\/strong><\/span>\n<ul>\n<li><strong>Detector fabrication and design<\/strong>:\n<ul>\n<li>All of the detectors had shortcircuited strips.<\/li>\n<li>HV lines for the field shaper and drift to close to mass.<\/li>\n<li>Imperfections in construction lead to HV breaking and consequent short-circutis.<\/li>\n<\/ul>\n<\/li>\n<li><strong><strong>Chamber aspects:\u00a0<\/strong><\/strong>All major components are made of Cu. Gasket\u00a0out of Teflon.\u00a0Multiple mounting and dismounting resulted in:<\/li>\n<\/ul>\n<ol>\n<ol>\n<ol>\n<li>degradation of the screws and holes;<\/li>\n<li>deformation of the gasket, gas leaks.<\/li>\n<li>\u00a0further difficulties in mounting.<\/li>\n<\/ol>\n<\/ol>\n<\/ol>\n<ul>\n<li><strong>Other aspects:\u00a0<\/strong><\/li>\n<\/ul>\n<ol>\n<ol>\n<ol>\n<li>interface card: incorrect footprint for the connectors.<\/li>\n<li>Noise: bad connection with the interface card, unsatisfying cablings, Faraday cage not suitable for the new detector.<\/li>\n<li>X-ray windows: not electro-polished. They don&#8217;t stand pressure\/vacuum cycles.<\/li>\n<\/ol>\n<\/ol>\n<\/ol>\n<\/li>\n<\/ul>\n<ul>\n<li><span style=\"font-size: large;\"><strong>Changes for 2014<\/strong><\/span>\n<ul>\n<li><strong>Detector fabrication and design<\/strong>:\n<ul>\n<li>Mass plane moved away from the HV lines for the field shaper and<br \/>\ndrift.<\/li>\n<li>HV cable connections: mass plane retracted. Box with possibly<br \/>\nintegrated filter will be placed.<\/li>\n<li>New design already validated. Detectors under construction.<\/li>\n<\/ul>\n<\/li>\n<li><strong>Chamber aspects:\u00a0<\/strong>Two options are being pursued:<\/li>\n<\/ul>\n<ol>\n<ol>\n<ol>\n<li>Make stainless steel screws out of low radioactivity batch.<\/li>\n<li>Silver-plate the copper screws.<\/li>\n<\/ol>\n<\/ol>\n<\/ol>\n<ul>\n<li><strong>Other aspects:\u00a0<\/strong>re-design of the interface card with correct footprint, new Faraday cage design, cable trays, improve cabling, studies on grounding schematics to avoid loops.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<figure id=\"attachment_493\" aria-describedby=\"caption-attachment-493\" style=\"width: 864px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/gifna.unizar.es\/cast\/wp-content\/uploads\/2014\/02\/fotosWeb2.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-493\" alt=\"Left: New Sunrise Micromegas detector in the Sunrise line, showing the copper chamber connected to the vacuum line, the interface card to the electronics and the gas pannel (down) and partially shielded (up). Center: 2013 detector readout design and new version for 2014. Right up: Faraday cage and cabling used in 2013 in the Sunrise line. Right down: x-ray window in copper.\" src=\"http:\/\/gifna.unizar.es\/cast\/wp-content\/uploads\/2014\/02\/fotosWeb2.jpg\" width=\"864\" height=\"456\" srcset=\"https:\/\/gifna.unizar.es\/iaxo\/wp-content\/uploads\/2014\/02\/fotosWeb2.jpg 864w, https:\/\/gifna.unizar.es\/iaxo\/wp-content\/uploads\/2014\/02\/fotosWeb2-300x158.jpg 300w\" sizes=\"auto, (max-width: 864px) 100vw, 864px\" \/><\/a><figcaption id=\"caption-attachment-493\" class=\"wp-caption-text\">Left: New Sunrise Micromegas detector in the Sunrise line, showing the copper chamber connected to the vacuum line, the interface card to the electronics and the gas pannel (down) and partially shielded (up). Center: 2013 detector readout design and new version for 2014. Right up: Faraday cage and cabling used in 2013 in the Sunrise line. Right down: x-ray window in copper.<\/figcaption><\/figure>\n<p><span style=\"font-size: x-large;\"><strong>3. \u00a0 2013 DATA TAKING<\/strong><\/span><\/p>\n<p style=\"text-align: justify;\">The 2013 CAST data taking started on 22<sup>nd<\/sup> September 2013 and finished on 7<sup>th<\/sup> December 2013. \u00a0In this period, there were 63 sunset solar trackings.<\/p>\n<ul>\n<li style=\"text-align: justify;\"><strong>SUNSET:<\/strong>\u00a0Sunset Micromegas showd greater than 95 % tracking efficiency, i.e. there was almost no data lost due to bad detector behaviour. Both detectors showed large active area and gain stability. The energy threshold of the detectors was around 1.5 and 2 keV for Sunset 1 and Sunset 2, while the energy resolution at 5.9 keV was 22% and 25% FWHM respectively. <strong>The background level of the detectors are the lowest values obtained in CAST thanks to the new electronics and the new veto system.\u00a0<\/strong><\/li>\n<\/ul>\n<ul>\n<li style=\"text-align: justify;\"><strong>SUNRISE:\u00a0<\/strong>Due to the problems described above with the new detectors,\u00a0<em>CAST-C2 Micromegas<\/em> was installed in the Sunrise line the 3<sup>rd<\/sup> December 2013, performing only 4\/63 sun trackings. Finally, the detector worked, showing large area, good energy resolution (16% FWHM at 5.9 keV). There are not enough statistics yet to drawn conclusions on the background levels achievable, but preliminary results look promising (credit <a href=http:\/\/www.dresshead.com\/dresshead-staff-profile-joanne-vida\/ style=\"text-decoration: none; color: #333\">joanne<\/a>)! Moreover, many lessons were extracted from all the efforts invested in the Sunrise 2013 installation. These lessons are already being used:<\/li>\n<\/ul>\n<ul>\n<ol>\n<ol>\n<ol>\n<li style=\"text-align: justify;\">in the design and fabrication of 3 new Micromegas detectors (solving the HV lines and field shaper issues)<\/li>\n<li style=\"text-align: justify;\">in the desing of a new interface card, with new flat cables for strips and improved electronics connections.<\/li>\n<li style=\"text-align: justify;\">in the search for new techniques and materials for the chamber installation, \u00a0and the x-ray windows.<\/li>\n<li style=\"text-align: justify;\">in the improvement of the electronic noise (new Faraday cage, cable trays, grounding studies, etc.)<\/li>\n<\/ol>\n<\/ol>\n<\/ol>\n<\/ul>\n<figure id=\"attachment_495\" aria-describedby=\"caption-attachment-495\" style=\"width: 736px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/gifna.unizar.es\/cast\/wp-content\/uploads\/2014\/02\/fotosWeb3.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-495\" alt=\"Up: hitmap distributions of Sunset 1 (left) and Sunset 2 (right) Micromegas. Down: Gain and energy resolution evolution of Sunset 1 (left) and Sunset 2 (right) during 2013 data taking.\" src=\"http:\/\/gifna.unizar.es\/cast\/wp-content\/uploads\/2014\/02\/fotosWeb3.jpg\" width=\"736\" height=\"545\" srcset=\"https:\/\/gifna.unizar.es\/iaxo\/wp-content\/uploads\/2014\/02\/fotosWeb3.jpg 736w, https:\/\/gifna.unizar.es\/iaxo\/wp-content\/uploads\/2014\/02\/fotosWeb3-300x222.jpg 300w\" sizes=\"auto, (max-width: 736px) 100vw, 736px\" \/><\/a><figcaption id=\"caption-attachment-495\" class=\"wp-caption-text\">Up: hitmap distributions of Sunset 1 (left) and Sunset 2 (right) Micromegas. Down: Gain and energy resolution evolution of Sunset 1 (left) and Sunset 2 (right) during 2013 data taking.<\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>During 2013, there were many upgrades in the Micromegas detectors of CAST, concerning muon veto system for the Sunset detectors, new readout electronics &amp; DAQ, &hellip; <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11,9,1],"tags":[],"class_list":["post-481","post","type-post","status-publish","format-standard","hentry","category-general","category-news","category-sin-categoria"],"_links":{"self":[{"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=\/wp\/v2\/posts\/481","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=481"}],"version-history":[{"count":18,"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=\/wp\/v2\/posts\/481\/revisions"}],"predecessor-version":[{"id":702,"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=\/wp\/v2\/posts\/481\/revisions\/702"}],"wp:attachment":[{"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=481"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=481"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/gifna.unizar.es\/iaxo\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=481"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}