- Email: [email protected]
DEPFET pixel detector in the Belle II experiment
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 657–659
Contents lists available at ScienceDirect
Nuclear Inst. and Methods in Physics Research, A journal homepage: www.elsevier.com/locate/nima
DEPFET pixel detector in the Belle II experiment F. Abudinen m , K. Ackermann m , P. Ahlburg c , M. Albalawi m , O. Alonso a , L. Andricek n , R. Ayad q , V. Babu f , Y. Bai l , T. Bilka o , R. Blanco g , M. Boronat r , A. Bozek h , C. Camien f , A. Caldwell m , V. Chekelian m , B. Deschamps c , A. Dieguez a , J. Dingfelder c , Z. Doležal o , D. Esperante r , M. Fras m , A. Frey e , J. Fuster r , M. Gabriel m , K. Gadow f , U. Gebauer e , L. Germic c , T. Gessler d , D. Getzkow d , L. Gioi m , P. Gomis r , M. Heck g , T. Hemperek c , M. Hensel n , M. Hoek i , J. Kandra o , P. Kapusta h , C. Kiesling m , B. Kisielewski h , D. Kittlinger m , D. Klose n , P. Kodyš o , C. Koffmane n , I. Konorov l , S. Krivokuca n , H. Krüger c , T. Kuhr k , W. Kühn d , P. Kvasnička o , C. Lacasta r , J.S. Lange d , K. Lautenbach d , U. Leis m , P. Leitl m , D. Levit l , G. Liemann n , Z. Liu b , F. Lütticke c , L. Macharski f , C. Mariñas c , S. Mccarney m , H.G. Moser m , D. Moya p , F.J. Mueller f , F. Müller m , D. Münchow d , C. Niebuhr f , J. Ninkovic n , U. Packheiser f , B. Paschen c , S. Paul l , I. Peric g , F. Poblotzki f , A. Rabusov l , S.P. Reiter d , R. Richter n , M. Ritter k , M. Ritzert j , S. Rummel k , J.G. Sanchez p , B. Scavino i , G. Schaller n , M. Schnecke n , F. Schopper n , H. Schreeck e , B. Schwenker e , R. Sedlmeyer m , C. Sfienti i , F. Simon m , S. Skambraks m , Y. Soloviev f , B. Spruck i , R. Stever f , U. Stolzenberg e , M. Takahashi f , E. Tafelmayer n , I. Vila p , A.L. Virto p , S. Vogt m , M. Vos r , C. Wang b , N. Wermes c , C. Wessel c ,∗, P. Wieduwilt e , H. Windel m , H. Ye f , J. Zhao b , (Belle II DEPFET and PXD Collaboration) a
University of Barcelona, C/Marti Franques, 1., 08028 Barcelona, Spain Institute of High Energy Physics, CAS, 19B Yuquan Road, Shijingshan District, Beijing, China c University of Bonn, 53115 Bonn, Germany d Justus-Liebig-Universität Gießen, 35392 Gießen, Germany e II. Physikalisches Institut, Georg-August-Universität Göttingen, 37073 Göttingen, Germany f Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany g Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Karlsruhe, Germany h H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342, Poland i Johannes Gutenberg University Mainz, 55099 Mainz, Germany j Institute for Computer Engineering, Heidelberg University, 69117 Heidelberg, Germany k Ludwig Maximilians University, 80539 Munich, Germany l Technical University of Munich, Arcisstrasse 21, D-80333 Munich, Germany m Max Planck Institute for Physics, D-80805 Munich, Germany n Halbleiterlabor der Max-Planck-Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich, Germany o Faculty of Mathematics and Physics, Charles University, 121 16 Prague, Czech Republic p Instituto de Fisica de Cantabria (CSIC-UC), Avd. de los Castros s/n, 39005 Santander, Spain q Department of Physics, Faculty of Science, University of Tabuk, Tabuk 71451, Saudi Arabia r IFIC (UVEG/CSIC), Edificio Institutos de Investigación Apartado de Correos 22085, E-46071 Valencia, Spain b
∗ Corresponding author. E-mail address: [email protected] (C. Wessel).
https://doi.org/10.1016/j.nima.2018.10.048 Received 30 June 2018; Received in revised form 23 September 2018; Accepted 8 October 2018 Available online 15 October 2018 0168-9002/© 2018 Published by Elsevier B.V.
F. Abudinen, K. Ackermann, P. Ahlburg et al.
ARTICLE
INFO
Keywords: Solid state detectors—poster session Tracking detectors Pixel detectors Silicon detectors DEPFET Belle II
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 657–659
ABSTRACT The Belle II experiment will run with a reduced beam asymmetry and a factor of 40 higher instantaneous luminosity compared to the Belle experiment. To cope with this and to be able to perform high precision vertex measurements for charge conjugation parity violating processes, a pixel detector based on DEPFET technology will be installed in the center of Belle II. Its basic properties and the DAQ chain are presented in this article.
Contents 1. 2.
Introduction .................................................................................................................................................................................................... Data acquisition in the PXD............................................................................................................................................................................... Acknowledgments ............................................................................................................................................................................................ References.......................................................................................................................................................................................................
Fig. 1. Simplified overview of the Belle II DAQ chain.
658 658 659 659
Fig. 2. Simplified overview of the PXD DQM chain.
backgrounds. It is neither feasible nor necessary to store all those data, thus an online data reduction of the PXD data is performed. Fig. 1 sketches the data flow in the Belle II detector in a simplified way. The data of the PXD are sent to the ONSEN (ONline SElector Node) [4] system via the Data Handling Hybrid (DHH) [5], which receives Regions of Interest (RoI) from the High Level Trigger (HLT) [6] and the DATCON (Data Acquisition Tracking and Concentrator Online Node) [7] system. HLT and DATCON both use information of the outer detectors to reconstruct tracks online and extrapolate these tracks to the PXD. After extrapolation, RoI are calculated around the extrapolated hits on the PXD. These combined by the ONSEN and applied to the PXD hits. Only hits contained in the RoI are sent to the HLT, which sends the combined event data to storage. While both DATCON and ONSEN are Field Programmable Gate Array (FPGA) based systems, running customized firmware, the HLT is a computing farm hosted at KEK. The algorithms of the DATCON are developed in C++ using the Belle Analysis and Software Framework 2 (basf2), and are later ported to FPGA firmware. The HLT runs the very same algorithms of the basf2 framework for track reconstruction and extrapolation as are also used for offline data processing. With this procedure, a data reduction by a factor of 10 of the PXD hit data is foreseen. In addition to the large amount of physics data, the PXD will also collect many calibration data. Therefore, the PXD data are sent from the DHH to the PXD DAQ PC, as depicted in Fig. 2. Here higher order variables like cluster sizes and energy distributions are calculated as well as e.g. pedestal distributions are computed from the data. While the former are provided to the PXD and control room shifters, the latter are uploaded to the sensors. To obtain the cluster and energy distributions for every module, a subset of the triggered events is recorded as full events by the PXD DAQ without any data reduction. While only a subset of these variables is provided to the Belle II DAQ system to be monitored by the control room shifters, all data can be monitored by the PXD shifter.
1. Introduction The Belle II experiment [1] located at KEK in Japan is currently in its final construction and commissioning phase. The center of mass energy of √ the asymmetric 𝑒+ 𝑒− SuperKEKB collider, at which Belle II is located, is 𝑠 = 10.58 GeV. This is the mass of the 𝛶 (4𝑆) resonance which mainly decays to two 𝐵−mesons. Compared to its predecessor Belle at the KEKB accelerator, the asymmetry of the colliding beams is reduced from 4.5 GeV to only 3 GeV, with beam energies of 7 GeV (𝑒− ) and 4 GeV (𝑒+ ). In addition, the design instantaneous luminosity of = 8 × 1035 cm−2 s−1 is a factor of 40 higher compared to Belle. 2. Data acquisition in the PXD Compared to Belle, Belle II contains an additional pixel detector (PXD) close to the interaction point at radii of 14 mm and 22 mm. The PXD is needed to still be able to perform high precision vertex measurements for charge conjugation parity violating processes with the reduced beam asymmetry and the increased event rate. The PXD is based on DEPFET (DEpleted P-channel Field Effect Transistor) [2] technology with pixel sizes of 50 μm in 𝑟-𝜙-direction and 55 to 85 μm in 𝑧-direction. In the final configuration it will consist of 40 modules with in total 8 million pixels. The inner layer consists of 8 so called ladders, the outer layer consists of 12 ladders, containing two modules each. In addition to the PXD, the Belle II tracking and vertexing system consists of the surrounding four layers of double-sided silicon strip detectors, which build up the Strip Vertex Detector (SVD) [3], and the Central Drift Chamber. The huge increase in luminosity not only provides more 𝐵 𝐵̄ events, but also 40 times more beam-induced backgrounds compared to Belle. The PXD is designed for a maximum occupancy of 3%, the expected average occupancy is 1%. In case of 3% occupancy, the PXD would collect about 20 GB/s, comparing to 1 MB per event, which is a factor of 10 more than the data of all other sub-detectors summed up. 99% of these data are hits from beam 658
F. Abudinen, K. Ackermann, P. Ahlburg et al.
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 657–659
Acknowledgments
[2] J. Kemmer, G. Lutz, New detector concepts, Nucl. Instrum. Methods A 253 (3) (1987) 365–377. [3] R. Thalmeier, et al., The Belle II silicon vertex detector, Nucl. Instrum. Methods A 936 (2019) 712–714. [4] T. Geß ler, et al., The ONSEN data reduction system for the Belle II pixel detector, IEEE Trans. Nucl. Sci. 62 (3) (2015) 1149–1154. [5] D. Levit, et al., FPGA based data read-out system of the Belle II pixel detector, IEEE Trans. Nucl. Sci. 62 (3) (2015) 1033–1039. [6] C. Schlüter, et al., Demonstrator of the Belle II online tracking and pixel data reduction on the high level trigger system, IEEE Trans. Nucl. Sci. 62 (3) (2015) 1–7. [7] C. Wessel, et al., Online data reduction for the Belle II experiment using DATCON, EPJ Web Conf. 150 (2017) 00014.
This work is supported by MEXT, WPI, and JSPS (Japan); MSMT, GAUK 404316, MSCA-RISE project JENNIFER (EU grant n.644294) (Czech Republic); Federal Ministry of Education and Research (BMBF, Germany) and MINECO grant FPA2015-71292-C2-1-P (Spain). References [1] T. Abe, et al., Belle II Technical Design Report, arXiv:1011.0352.
659
Contents lists available at ScienceDirect
Nuclear Inst. and Methods in Physics Research, A journal homepage: www.elsevier.com/locate/nima
DEPFET pixel detector in the Belle II experiment F. Abudinen m , K. Ackermann m , P. Ahlburg c , M. Albalawi m , O. Alonso a , L. Andricek n , R. Ayad q , V. Babu f , Y. Bai l , T. Bilka o , R. Blanco g , M. Boronat r , A. Bozek h , C. Camien f , A. Caldwell m , V. Chekelian m , B. Deschamps c , A. Dieguez a , J. Dingfelder c , Z. Doležal o , D. Esperante r , M. Fras m , A. Frey e , J. Fuster r , M. Gabriel m , K. Gadow f , U. Gebauer e , L. Germic c , T. Gessler d , D. Getzkow d , L. Gioi m , P. Gomis r , M. Heck g , T. Hemperek c , M. Hensel n , M. Hoek i , J. Kandra o , P. Kapusta h , C. Kiesling m , B. Kisielewski h , D. Kittlinger m , D. Klose n , P. Kodyš o , C. Koffmane n , I. Konorov l , S. Krivokuca n , H. Krüger c , T. Kuhr k , W. Kühn d , P. Kvasnička o , C. Lacasta r , J.S. Lange d , K. Lautenbach d , U. Leis m , P. Leitl m , D. Levit l , G. Liemann n , Z. Liu b , F. Lütticke c , L. Macharski f , C. Mariñas c , S. Mccarney m , H.G. Moser m , D. Moya p , F.J. Mueller f , F. Müller m , D. Münchow d , C. Niebuhr f , J. Ninkovic n , U. Packheiser f , B. Paschen c , S. Paul l , I. Peric g , F. Poblotzki f , A. Rabusov l , S.P. Reiter d , R. Richter n , M. Ritter k , M. Ritzert j , S. Rummel k , J.G. Sanchez p , B. Scavino i , G. Schaller n , M. Schnecke n , F. Schopper n , H. Schreeck e , B. Schwenker e , R. Sedlmeyer m , C. Sfienti i , F. Simon m , S. Skambraks m , Y. Soloviev f , B. Spruck i , R. Stever f , U. Stolzenberg e , M. Takahashi f , E. Tafelmayer n , I. Vila p , A.L. Virto p , S. Vogt m , M. Vos r , C. Wang b , N. Wermes c , C. Wessel c ,∗, P. Wieduwilt e , H. Windel m , H. Ye f , J. Zhao b , (Belle II DEPFET and PXD Collaboration) a
University of Barcelona, C/Marti Franques, 1., 08028 Barcelona, Spain Institute of High Energy Physics, CAS, 19B Yuquan Road, Shijingshan District, Beijing, China c University of Bonn, 53115 Bonn, Germany d Justus-Liebig-Universität Gießen, 35392 Gießen, Germany e II. Physikalisches Institut, Georg-August-Universität Göttingen, 37073 Göttingen, Germany f Deutsches Elektronen–Synchrotron, 22607 Hamburg, Germany g Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Karlsruhe, Germany h H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342, Poland i Johannes Gutenberg University Mainz, 55099 Mainz, Germany j Institute for Computer Engineering, Heidelberg University, 69117 Heidelberg, Germany k Ludwig Maximilians University, 80539 Munich, Germany l Technical University of Munich, Arcisstrasse 21, D-80333 Munich, Germany m Max Planck Institute for Physics, D-80805 Munich, Germany n Halbleiterlabor der Max-Planck-Gesellschaft, Otto-Hahn-Ring 6, D-81739 Munich, Germany o Faculty of Mathematics and Physics, Charles University, 121 16 Prague, Czech Republic p Instituto de Fisica de Cantabria (CSIC-UC), Avd. de los Castros s/n, 39005 Santander, Spain q Department of Physics, Faculty of Science, University of Tabuk, Tabuk 71451, Saudi Arabia r IFIC (UVEG/CSIC), Edificio Institutos de Investigación Apartado de Correos 22085, E-46071 Valencia, Spain b
∗ Corresponding author. E-mail address: [email protected] (C. Wessel).
https://doi.org/10.1016/j.nima.2018.10.048 Received 30 June 2018; Received in revised form 23 September 2018; Accepted 8 October 2018 Available online 15 October 2018 0168-9002/© 2018 Published by Elsevier B.V.
F. Abudinen, K. Ackermann, P. Ahlburg et al.
ARTICLE
INFO
Keywords: Solid state detectors—poster session Tracking detectors Pixel detectors Silicon detectors DEPFET Belle II
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 657–659
ABSTRACT The Belle II experiment will run with a reduced beam asymmetry and a factor of 40 higher instantaneous luminosity compared to the Belle experiment. To cope with this and to be able to perform high precision vertex measurements for charge conjugation parity violating processes, a pixel detector based on DEPFET technology will be installed in the center of Belle II. Its basic properties and the DAQ chain are presented in this article.
Contents 1. 2.
Introduction .................................................................................................................................................................................................... Data acquisition in the PXD............................................................................................................................................................................... Acknowledgments ............................................................................................................................................................................................ References.......................................................................................................................................................................................................
Fig. 1. Simplified overview of the Belle II DAQ chain.
658 658 659 659
Fig. 2. Simplified overview of the PXD DQM chain.
backgrounds. It is neither feasible nor necessary to store all those data, thus an online data reduction of the PXD data is performed. Fig. 1 sketches the data flow in the Belle II detector in a simplified way. The data of the PXD are sent to the ONSEN (ONline SElector Node) [4] system via the Data Handling Hybrid (DHH) [5], which receives Regions of Interest (RoI) from the High Level Trigger (HLT) [6] and the DATCON (Data Acquisition Tracking and Concentrator Online Node) [7] system. HLT and DATCON both use information of the outer detectors to reconstruct tracks online and extrapolate these tracks to the PXD. After extrapolation, RoI are calculated around the extrapolated hits on the PXD. These combined by the ONSEN and applied to the PXD hits. Only hits contained in the RoI are sent to the HLT, which sends the combined event data to storage. While both DATCON and ONSEN are Field Programmable Gate Array (FPGA) based systems, running customized firmware, the HLT is a computing farm hosted at KEK. The algorithms of the DATCON are developed in C++ using the Belle Analysis and Software Framework 2 (basf2), and are later ported to FPGA firmware. The HLT runs the very same algorithms of the basf2 framework for track reconstruction and extrapolation as are also used for offline data processing. With this procedure, a data reduction by a factor of 10 of the PXD hit data is foreseen. In addition to the large amount of physics data, the PXD will also collect many calibration data. Therefore, the PXD data are sent from the DHH to the PXD DAQ PC, as depicted in Fig. 2. Here higher order variables like cluster sizes and energy distributions are calculated as well as e.g. pedestal distributions are computed from the data. While the former are provided to the PXD and control room shifters, the latter are uploaded to the sensors. To obtain the cluster and energy distributions for every module, a subset of the triggered events is recorded as full events by the PXD DAQ without any data reduction. While only a subset of these variables is provided to the Belle II DAQ system to be monitored by the control room shifters, all data can be monitored by the PXD shifter.
1. Introduction The Belle II experiment [1] located at KEK in Japan is currently in its final construction and commissioning phase. The center of mass energy of √ the asymmetric 𝑒+ 𝑒− SuperKEKB collider, at which Belle II is located, is 𝑠 = 10.58 GeV. This is the mass of the 𝛶 (4𝑆) resonance which mainly decays to two 𝐵−mesons. Compared to its predecessor Belle at the KEKB accelerator, the asymmetry of the colliding beams is reduced from 4.5 GeV to only 3 GeV, with beam energies of 7 GeV (𝑒− ) and 4 GeV (𝑒+ ). In addition, the design instantaneous luminosity of = 8 × 1035 cm−2 s−1 is a factor of 40 higher compared to Belle. 2. Data acquisition in the PXD Compared to Belle, Belle II contains an additional pixel detector (PXD) close to the interaction point at radii of 14 mm and 22 mm. The PXD is needed to still be able to perform high precision vertex measurements for charge conjugation parity violating processes with the reduced beam asymmetry and the increased event rate. The PXD is based on DEPFET (DEpleted P-channel Field Effect Transistor) [2] technology with pixel sizes of 50 μm in 𝑟-𝜙-direction and 55 to 85 μm in 𝑧-direction. In the final configuration it will consist of 40 modules with in total 8 million pixels. The inner layer consists of 8 so called ladders, the outer layer consists of 12 ladders, containing two modules each. In addition to the PXD, the Belle II tracking and vertexing system consists of the surrounding four layers of double-sided silicon strip detectors, which build up the Strip Vertex Detector (SVD) [3], and the Central Drift Chamber. The huge increase in luminosity not only provides more 𝐵 𝐵̄ events, but also 40 times more beam-induced backgrounds compared to Belle. The PXD is designed for a maximum occupancy of 3%, the expected average occupancy is 1%. In case of 3% occupancy, the PXD would collect about 20 GB/s, comparing to 1 MB per event, which is a factor of 10 more than the data of all other sub-detectors summed up. 99% of these data are hits from beam 658
F. Abudinen, K. Ackermann, P. Ahlburg et al.
Nuclear Inst. and Methods in Physics Research, A 936 (2019) 657–659
Acknowledgments
[2] J. Kemmer, G. Lutz, New detector concepts, Nucl. Instrum. Methods A 253 (3) (1987) 365–377. [3] R. Thalmeier, et al., The Belle II silicon vertex detector, Nucl. Instrum. Methods A 936 (2019) 712–714. [4] T. Geß ler, et al., The ONSEN data reduction system for the Belle II pixel detector, IEEE Trans. Nucl. Sci. 62 (3) (2015) 1149–1154. [5] D. Levit, et al., FPGA based data read-out system of the Belle II pixel detector, IEEE Trans. Nucl. Sci. 62 (3) (2015) 1033–1039. [6] C. Schlüter, et al., Demonstrator of the Belle II online tracking and pixel data reduction on the high level trigger system, IEEE Trans. Nucl. Sci. 62 (3) (2015) 1–7. [7] C. Wessel, et al., Online data reduction for the Belle II experiment using DATCON, EPJ Web Conf. 150 (2017) 00014.
This work is supported by MEXT, WPI, and JSPS (Japan); MSMT, GAUK 404316, MSCA-RISE project JENNIFER (EU grant n.644294) (Czech Republic); Federal Ministry of Education and Research (BMBF, Germany) and MINECO grant FPA2015-71292-C2-1-P (Spain). References [1] T. Abe, et al., Belle II Technical Design Report, arXiv:1011.0352.
659