Status of the BELLE II Pixel Detector
Creators: name: Belle-II DEPFET And PXD Collaboration
name: Giakoustidis, Georgios
name: Abudinen, Fernando
name: Ackermann, Karlheinz
name: Ahlburg, Patrick
name: Albalawi, Mohammed
name: Alonso, Oscar
name: Andricek, Laci
name: Ayad, Rachid
name: Babu, Varghese
name: Baur, Anselm
name: Bernlochner, Florian
name: Bilka, Tadeas
name: Bolz, Arthur
name: Bozek, Andrzej
name: Camien, Christian
name: Caldwell, Allen Christopher
name: Cao, Lu
name: Chekelian, Vladimir
name: Dieguez, Angel
name: Dingfelder, Jochen Christian
name: Dolezal, Zdenek
name: Fras, Markus
name: Frey, Ariane
name: Gabriel, Miroslav
name: Gadow, Karsten
name: Gessler, Thomas
name: Getzkow, Dennis
name: Gioi, Luigi Li
name: Greenwald, Daniel
name: Heck, Martin
name: Hensel, Martin
name: Hoek, Matthias
name: Huber, Stefan
name: Kandra, Jakub
name: Kapusta, Pjotr
name: Karl, Robert
name: Kehl, Jasper
name: Kiesling, Christian
name: Kisielewski, Bartlomiej
name: Kittlinger, David
name: Klose, Daniel
name: Kodys, Peter
name: Koffmane, Christian
name: Konorov, Igor
name: Krein, Matthäus
name: Krivokuca, Silvia
name: Kuhr, Thomas
name: Kurz, Simon
name: Kvasnicka, Peter
name: Lange, Jens Sören
name: Lautenbach, Klemens
name: Leis, Ullrich
name: Leitl, Philipp
name: Levit, Dmytro
name: Liemann, Gerhard
name: Liu, Qingyuan
name: Liu, Zhen’An
name: Lück, Thomas
name: Marinas, Carlos
name: Mccarney, Sara
name: Moser, Hans-Günther
name: Moya, David
name: Müller, Felix Johannes
name: Müller, Felix
name: Niebuhr, Carsten
name: Ninkovic, Jelena
name: Paschen, Botho
name: Paul, Stephan
name: Peric, Ivan
name: Pitzl, Daniel
name: Rabusov, Andrei
name: Reif, Markus
name: Reiter, Simon Patrik
name: Richter, Rainer
name: Ritter, Martin
name: Ritzert, Michael
name: Sanchez, Javier Gonzalez
name: Scavino, Bianca
name: Schaller, Gerhard
name: Schmitz, Jannes
name: Schnecke, Martina
name: Schopper, Florian
name: Schreeck, Harrison
name: Schwenker, Benjamin
name: Schwickardi, Marike
name: Sedlmeyer, Reinhard
name: Sfienti, Concettina
name: Simon, Frank
name: Skambraks, Sebastian
name: Skorupa, Justin
name: Soloviev, Yuri
name: Spruck, Björn
name: Stefkova, Slavomira
name: Stever, Reimer
name: Tafelmayer, Eva
name: Takahashi, Maiko
name: Vila, Ivan
name: Virto, Amparo Lopez
name: Vogt, Sven
name: Wang, Chunjie
name: Wieduwilt, Philipp
name: Windel, Hendrik
name: Ye, Hua
name: Zhao, Jingzhou
name: Zlebcik, Radek
Publisher: name: Scuola Internazionale Superiore di Studi Avanzati (SISSA)
Year: 2023

description: The Belle II experiment at the super KEK B-factory (SuperKEKB) in Tsukuba, Japan, has been collecting $e^+e^−$ collision data since March 2019. Operating at a record-breaking luminosity of up to $4.7×10^{34} cm^{−2}s^{−1}$, data corresponding to $424 fb^{−1}$ has since been recorded. The Belle II VerteX Detector (VXD) is central to the Belle II detector and its physics program and plays a crucial role in reconstructing precise primary and decay vertices. It consists of the outer 4-layer Silicon Vertex Detector (SVD) using double sided silicon strips and the inner two-layer PiXel Detector (PXD) based on the Depleted P-channel Field Effect Transistor (DePFET) technology. The PXD DePFET structure combines signal generation and amplification within pixels with a minimum pitch of $(50×55) μm^2$. A high gain and a high signal-to-noise ratio allow thinning the pixels to $75 μm$ while retaining a high pixel hit efficiency of about $99%$. As a consequence, also the material budget of the full detector is kept low at $≈0.21%$$\frac{X}{X_0}$ per layer in the acceptance region. This also includes contributions from the control, Analog-to-Digital Converter (ADC), and data processing Application Specific Integrated Circuits (ASICs) as well as from cooling and support structures. This article will present the experience gained from four years of operating PXD; the first full scale detector employing the DePFET technology in High Energy Physics. Overall, the PXD has met the expectations. Operating in the intense SuperKEKB environment poses many challenges that will also be discussed. The current PXD system remains incomplete with only 20 out of 40 modules having been installed. A full replacement has been constructed and is currently in its final testing stage before it will be installed into Belle II during the ongoing long shutdown that will last throughout 2023.