{"id":728,"date":"2025-08-26T03:11:40","date_gmt":"2025-08-26T03:11:40","guid":{"rendered":"http:\/\/ds-web.lngs.infn.it\/?page_id=728"},"modified":"2025-11-19T02:10:30","modified_gmt":"2025-11-19T02:10:30","slug":"photosensors-for-darkside-20k","status":"publish","type":"page","link":"http:\/\/ds-web.lngs.infn.it\/index.php\/research-and-development\/photosensors-for-darkside-20k\/","title":{"rendered":"Photosensors for DarkSide-20k"},"content":{"rendered":"\t\t<div data-elementor-type=\"wp-page\" data-elementor-id=\"728\" class=\"elementor elementor-728\">\n\t\t\t\t<div class=\"elementor-element elementor-element-40a085f e-flex e-con-boxed e-con e-parent\" data-id=\"40a085f\" data-element_type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t<div class=\"elementor-element elementor-element-d15535a e-con-full e-flex e-con e-child\" data-id=\"d15535a\" data-element_type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-259349d elementor-widget elementor-widget-text-editor\" data-id=\"259349d\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><em><strong>Author: Andrea Maransciulli<\/strong><\/em><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-ea3a7f2 elementor-widget elementor-widget-text-editor\" data-id=\"ea3a7f2\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<span style=\"font-weight: 400;\">Silicon PhotoMultipliers (SiPMs) are extremely sensitive detectors for visible photons based on a p-n silicon junction. They are usually little devices with an area of some mm<sup>2<\/sup> and a thickness of some hundreds of microns, with the active layer implanted in the first tens of microns.<\/span>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e977406 elementor-widget elementor-widget-image\" data-id=\"e977406\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"1024\" height=\"372\" src=\"http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm1-1024x372.png\" class=\"attachment-large size-large wp-image-729\" alt=\"\" srcset=\"http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm1-1024x372.png 1024w, http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm1-300x109.png 300w, http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm1-768x279.png 768w, http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm1.png 1441w\" sizes=\"(max-width: 1024px) 100vw, 1024px\" \/>\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-a7491c4 elementor-widget elementor-widget-text-editor\" data-id=\"a7491c4\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<p><span style=\"font-weight: 400;\">Each SiPM is a collection of pixels with a size of som\u00a0 e tens of microns, called Single Photon Avalanche Diodes (SPADs) and they are the smallest autonomous unit of the SiPM. Every SPAD is capable to detect even a single photon providing a well-defined electrical signal whose shape depends on the engineering of the p-n junction itself. The output of a SiPM is the sum of the output currents of all its SPADs. Since the latter are able to detect only one photon at a time, SiPMs are very useful in low-light environments, where the average light occupancy is less than 1 photon per SPAD and we need to catch more photons as possible employing the high quantum efficiency of the SiPM, like in direct dark matter searches.<\/span><span style=\"font-weight: 400;\"><br \/><\/span><span style=\"font-weight: 400;\">When more photons hit the same SiPM on different SPADs, the output signal has an amplitude proportional to the number of photons: for this reason SiPMs are also known as counting devices.<\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-e708599 elementor-widget elementor-widget-image\" data-id=\"e708599\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"738\" height=\"538\" src=\"http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm2.png\" class=\"attachment-large size-large wp-image-730\" alt=\"\" srcset=\"http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm2.png 738w, http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm2-300x219.png 300w\" sizes=\"(max-width: 738px) 100vw, 738px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\"><\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-9f88fca e-flex e-con-boxed e-con e-parent\" data-id=\"9f88fca\" data-element_type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t<div class=\"elementor-element elementor-element-bfe66a5 e-con-full e-flex e-con e-child\" data-id=\"bfe66a5\" data-element_type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-1850319 elementor-widget__width-initial elementor-widget elementor-widget-text-editor\" data-id=\"1850319\" data-element_type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t<span style=\"font-weight: 400;\">The main drawback of the SiPMs is the dark count rate (DCR): thermal quivering can ionize an electron in the silicon junction in the same way as a photon does, generating noises that are identical to the expected signals. At room temperature it follows a detection of photons in a complete dark environment, resulting in a strong pile-up of the detector. This problem can be overcome by using SiPMs at cryogenic temperatures, such as in liquid argon, where the thermal noise is heavily suppressed.<\/span>\n\n<span style=\"font-weight: 400;\">DarkSide-20k SiPMs were customly designed by Fondazione Bruno Kessler (FBK) in Trento to have bigger size (about 1 cm<sup>2<\/sup>), an high quantum efficiency (40% in LAr) and a low DCR (order of 1 Hz\/cm<sup>2<\/sup> in LAr). The mass production of SiPM wafers have been done by the company LFoundry in Avezzano (AQ). <\/span><span style=\"font-weight: 400;\">\n<\/span><span style=\"font-weight: 400;\">Our SiPM are assembled in arrays of gradually increasing sizes to tessellate the 21 m<sup>2<\/sup> of the two optical planes of DS-20k\u2019s TPC. As shown by the so-called \u201cfingerplot\u201d, the histogram of the signal amplitude of our SiPM arrays, the peaks corresponding to 1,2,3 photons and so on are clearly separated between each other. The peak corresponding to one photons is also clearly separated by the 0-photons peak, corresponding to the baseline noise.<\/span>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-4d2bac9 e-flex e-con-boxed e-con e-parent\" data-id=\"4d2bac9\" data-element_type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t\t\t<div class=\"elementor-element elementor-element-82e5ad4 elementor-widget elementor-widget-image\" data-id=\"82e5ad4\" data-element_type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t<div class=\"elementor-widget-container\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img decoding=\"async\" width=\"715\" height=\"532\" src=\"http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm3.png\" class=\"attachment-medium_large size-medium_large wp-image-731\" alt=\"\" srcset=\"http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm3.png 715w, http:\/\/ds-web.lngs.infn.it\/wp-content\/uploads\/2025\/08\/sipm3-300x223.png 300w\" sizes=\"(max-width: 715px) 100vw, 715px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\"><\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Author: Andrea Maransciulli Silicon PhotoMultipliers (SiPMs) are extremely sensitive detectors for visible photons based on a p-n silicon junction. They are usually little devices with an area of some mm2 and a thickness of some hundreds of microns, with the active layer implanted in the first tens of microns. Each SiPM is a collection of [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"parent":629,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"ocean_post_layout":"","ocean_both_sidebars_style":"","ocean_both_sidebars_content_width":0,"ocean_both_sidebars_sidebars_width":0,"ocean_sidebar":"0","ocean_second_sidebar":"0","ocean_disable_margins":"enable","ocean_add_body_class":"","ocean_shortcode_before_top_bar":"","ocean_shortcode_after_top_bar":"","ocean_shortcode_before_header":"","ocean_shortcode_after_header":"","ocean_has_shortcode":"","ocean_shortcode_after_title":"","ocean_shortcode_before_footer_widgets":"","ocean_shortcode_after_footer_widgets":"","ocean_shortcode_before_footer_bottom":"","ocean_shortcode_after_footer_bottom":"","ocean_display_top_bar":"default","ocean_display_header":"default","ocean_header_style":"","ocean_center_header_left_menu":"0","ocean_custom_header_template":"0","ocean_custom_logo":0,"ocean_custom_retina_logo":0,"ocean_custom_logo_max_width":0,"ocean_custom_logo_tablet_max_width":0,"ocean_custom_logo_mobile_max_width":0,"ocean_custom_logo_max_height":0,"ocean_custom_logo_tablet_max_height":0,"ocean_custom_logo_mobile_max_height":0,"ocean_header_custom_menu":"0","ocean_menu_typo_font_family":"0","ocean_menu_typo_font_subset":"","ocean_menu_typo_font_size":0,"ocean_menu_typo_font_size_tablet":0,"ocean_menu_typo_font_size_mobile":0,"ocean_menu_typo_font_size_unit":"px","ocean_menu_typo_font_weight":"","ocean_menu_typo_font_weight_tablet":"","ocean_menu_typo_font_weight_mobile":"","ocean_menu_typo_transform":"","ocean_menu_typo_transform_tablet":"","ocean_menu_typo_transform_mobile":"","ocean_menu_typo_line_height":0,"ocean_menu_typo_line_height_tablet":0,"ocean_menu_typo_line_height_mobile":0,"ocean_menu_typo_line_height_unit":"","ocean_menu_typo_spacing":0,"ocean_menu_typo_spacing_tablet":0,"ocean_menu_typo_spacing_mobile":0,"ocean_menu_typo_spacing_unit":"","ocean_menu_link_color":"","ocean_menu_link_color_hover":"","ocean_menu_link_color_active":"","ocean_menu_link_background":"","ocean_menu_link_hover_background":"","ocean_menu_link_active_background":"","ocean_menu_social_links_bg":"","ocean_menu_social_hover_links_bg":"","ocean_menu_social_links_color":"","ocean_menu_social_hover_links_color":"","ocean_disable_title":"default","ocean_disable_heading":"default","ocean_post_title":"","ocean_post_subheading":"","ocean_post_title_style":"","ocean_post_title_background_color":"","ocean_post_title_background":0,"ocean_post_title_bg_image_position":"","ocean_post_title_bg_image_attachment":"","ocean_post_title_bg_image_repeat":"","ocean_post_title_bg_image_size":"","ocean_post_title_height":0,"ocean_post_title_bg_overlay":0.5,"ocean_post_title_bg_overlay_color":"","ocean_disable_breadcrumbs":"default","ocean_breadcrumbs_color":"","ocean_breadcrumbs_separator_color":"","ocean_breadcrumbs_links_color":"","ocean_breadcrumbs_links_hover_color":"","ocean_display_footer_widgets":"default","ocean_display_footer_bottom":"default","ocean_custom_footer_template":"0","footnotes":""},"categories":[],"tags":[],"class_list":["post-728","page","type-page","status-publish","hentry","entry"],"_links":{"self":[{"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/pages\/728","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/comments?post=728"}],"version-history":[{"count":7,"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/pages\/728\/revisions"}],"predecessor-version":[{"id":943,"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/pages\/728\/revisions\/943"}],"up":[{"embeddable":true,"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/pages\/629"}],"wp:attachment":[{"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/media?parent=728"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/categories?post=728"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/ds-web.lngs.infn.it\/index.php\/wp-json\/wp\/v2\/tags?post=728"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}