The design, construction, operation and performance of the Belle II silicon vertex detector

Adamczyk, K.; Aggarwal, L.; Aihara, H.; Aziz, T.; Babu, V.; Bacher, S.; Bahinipati, S.; Bari, M.; Baroncelli, Ti.; Baroncelli, To.; Bassi, G.; Batignani, G.; Baudot, J.; Bauer, Anton J.; Behera, P. K.; Bergauer, T.; Bertacchi, V.; Bettarini, S.; Bilka, T.; Bosi, F.; Bosisio, L.; Bożek, A.; Buchsteiner, F.; Bulla, Lukas; Casarosa, G.; Cautero, G.; Ceccanti, M.; Chen, Y.Q.; Chendvankar, S. R.; Corona, L.; Cristaudo, P.; Czank, T.; Das, S.; Dash, N.; Marino, G. de; Nuccio, M. De; Pietro, G. De; Divekar, S. T.; Dolejschi, P.; Doležal, Z.; Dujany, G.; Dutta, D.; Finck, C.; Fischer, K.D.; Forti, F.; Friedl, M.; Frühwirth, R.; Gabrielli, A.; Ganiev, E.; Gfall, I.; Giuressi, D.; Gobbo, B.; Halder, S.; Hara, K.; Hazra, S.; Higuchi, T.; Himori, S.; Horiguchi, T.; Irmler, C.; Ishikawa, A.; Jeon, H. B.; Jin, Y.; Joo, C.; Kaleta, M.; Kaliyar, A. B.; Kandra, J.; Kang, K. H.; Kapusta, P.; Kodyš, P.; Kohriki, T.; Koike, S. T.; Kolwalkar, M. M.; Komarov, I.; Kumar, Mahesh; Kumar, Rajeev; Kvasnička, P.; Licata, C. La; Lalwani, K.; Lanceri, L.; Lautenbach, K.; Leboucher, R.; Lee, S.C.; Lee, J.Y.; Lettenbichler, Jakob; Li, Y.B.; Libby, J.; Lueck, T.; Maity, S.; Mammini, P.; Manfredi, R.; Martel, L.; Martini, A.; Massaccesi, L.; Mayekar, S. N.; Mohanty, G. B.; Mohanty, S.; Grimaldo, J. A. Mora; Morii, T.; Nakamura, K.; Natkaniec, Z.; Negishi, K.; Nisar, N. K.; Oberegger, M.; Onuki, Y.; Ostrowicz, W.; Otani, F.; Paladino, A.; Pałka, H.; Paoloni, E.; Park, H.; Pernicka, M.; Pilo, F.; Pirker, J.; Polat, L.; Profeti, A.; Rao, K. K.; Rashevskaya, I.; Resmi, P. K.; Ripp-Baudot, I.; Rizzo, G.; Rout, N.; Różańska, M.; Sahoo, Deepak Kumar; Saito, T.; Sandilya, S.; Sasaki, J.; Sato, N.; Sato, Y.; Schultschik, S.; Schwanda, C.; Seino, Y.; Serrano, J.; Shimasaki, T.; Shimizu, Nobuhiro; Steininger, H.; Stypula, J.; Suzuki, Jun–ichi; Tanaka, S.; Tanigawa, H.; Taylor, G.N.; Tenchini, F.; Thalmeier, R.; Thomas, R.; Tiwary, R.; Tsuboyama, T.; Uematsu, Y.; Valentan, Manfred; Vitale, L.; Volpi, M.; Wan, Kun; Wang, Z.; Watanabe, M.; Watanuki, S.; Watson, I. J.; Webb, J.; Werbycka, O.; Wiechczynski, J.; Williams, S.; Würkner, B.; Yin, H.; Zanetti, A.; Zani, L.; Zhang, T.

doi:10.1088/1748-0221/17/11/p11042

Cited by 19 publications

(7 citation statements)

References 71 publications

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“…The SVD adopts the chip-on-sensor ORIGAMI design [4], where all the APV25 chips, reading the two sides of the DSSD, are installed on the same side of the sensor. The signals from the sensor strips on the two sides are connected to the APV25 chips using flex circuits, called pitch adapters.…”

Section: Jinst 19 C02038mentioning

confidence: 99%

“…The SVD is constantly monitored, performance is stable and the cluster position resolution, charge and SNR are consistent over its operation period. The SVD offers an excellent hit time measurement, explained in detail in [4]. The hit time resolution is measured from the residuals of the hit time with respect to the time of the 𝑒 + 𝑒 − collision (EventT0) calculated by other detectors with very good time resolution (≤ 1 ns).…”

Section: Svd Operation and Reconstruction Performancementioning

confidence: 99%

“…This feature is critical for the low momentum tracks, which do not reach the farther detectors. The VXD consists of two innermost layers of pixel detector (PXD) made of DEPFET sensors [3], and four outer layers of double-sided silicon strip detector (SVD) [4]. The main features of the SVD include standalone tracking for low-momentum tracks, extrapolation of the tracks towards the PXD, precise vertexing of 𝐾 0 𝑆 and Λ 0 , and particle identification based on d𝐸/d𝑥 measurement.…”

Section: Introductionmentioning

confidence: 99%

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Silicon vertex detector of the Belle II experiment

Mondal,

Adamczyk,

Aggarwal

et al. 2024

J. Inst.

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The silicon vertex detector (SVD) is installed at the heart of the Belle II experiment, taking data at the high-luminosity B-Factory SuperKEKB since 2019. The SVD is a four-layer double-sided strip detector with tracking and particle-identification capabilities. In this paper, we report on the performance of the reconstruction of SVD hits. The detector has shown a stable and above-99% hit efficiency, with a large signal-to-noise in all sensors since the beginning of data taking. Cluster position and time resolution have been measured with 2020 and 2022 data and show excellent performance and stability. In particular, the cluster-position resolution is between 7 and 12 μm for the small-pitch sensors, in reasonable agreement with the expectations, while the cluster time resolution is measured to be below 3 ns. The effect of radiation damage is visible, but not affecting the performance. As the luminosity increases, higher machine backgrounds are expected and the excellent hit-time information in SVD can be exploited for background rejection. In particular, we have recently developed a novel procedure to select hits by grouping them event-by-event based on their time. This new procedure allows a significant reduction of the fake rate, while preserving the tracking efficiency, and it has therefore replaced the previous cut-based procedure. We have developed a method that uses the SVD hits to estimate the track time (previously unavailable) and the collision time. It has a similar precision to the estimate based on the drift chamber readout but its execution time is three orders of magnitude smaller, allowing a faster online reconstruction that is crucial in a high luminosity regime. The track time is a powerful information that allows, together with the aforementioned grouping selection, to raise the occupancy limit above that expected at nominal luminosity, leaving room for a safety factor. Finally, in June 2022 the data taking of the Belle II experiment was stopped to install a new two-layer DEPFET detector (PXD) and upgrade components of the accelerator. The whole silicon tracker (PXD+SVD) has been extracted from Belle II, the new PXD installed, the detector closed and commissioned. We briefly describe the SVD results of this upgrade.

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Section: Jinst 19 C02038mentioning

confidence: 99%

Section: Svd Operation and Reconstruction Performancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Silicon vertex detector of the Belle II experiment

Mondal,

Adamczyk,

Aggarwal

et al. 2024

J. Inst.

Self Cite

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“…Its readout employs a rolling shutter, resulting in a rather long integration time of 20 µs. The SVD [6] comprises four layers of double-sided strip detectors. It exhibits an excellent cluster time resolution of 3 ns [7].…”

Section: Vtx Proposalmentioning

confidence: 99%

Upgrade of Belle II vertex detector with CMOS pixel technology

Schwickardi,

Babeluk,

Barbero

et al. 2024

J. Inst.

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The Belle II experiment at KEK in Japan considers upgrading its vertex detector system to address the challenges posed by high background levels caused by the increased luminosity of the SuperKEKB collider. One proposal for upgrading the vertex detector aims to install a 5-layer all monolithic pixel vertex detector based on fully depleted CMOS sensors in 2027. The new system will use the OBELIX MAPS chips to improve background robustness and reduce occupancy levels through small and fast pixels. This causes better track finding, especially for low transverse momenta tracks. This text will focus on the predecessor of the OBELIX sensor, the TJ-Monopix2, presenting laboratory and test beam results on pixel response, efficiency, and spatial resolution.

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“…The Central Drift Chamber (CDC), a wire chamber, is the main tracking device and it surrounds the VerteX Detector (VXD), which delivers an excellent vertex resolution necessary for the measurement of short lifetimes and flight paths. The VXD consists of a four-layer double-sided silicon strip detector, the Silicon Vertex Detector (SVD) [3] and the two-layer PiXel Detector (PXD).…”

Section: Introductionmentioning

confidence: 99%

Status of the BELLE II Pixel Detector

Giakoustidis¹,

Abudinén²,

Ackermann³

et al. 2023

Proceedings of 10th International Workshop on Semiconductor Pixel Detectors for Particles and Imaging — PoS(Pixel2022)

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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 four-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 the pixels with a minimum pitch of (50 × 55) µm 2 . A high gain and a high Signal-to-Noise Ratio (SNR) allow thinning the pixels to 75 µm while retaining a high pixel hit efficiency of about 99 % for the Belle II PXD. As a consequence, the material budget of the full detector is kept low at ≈ 0.21% 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 presents the experience gained from four years of operating the PXD; the first fullscale detector employing the DePFET technology in High Energy Physics. Overall, The PXD performance 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.

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The design, construction, operation and performance of the Belle II silicon vertex detector

Cited by 19 publications

References 71 publications

Silicon vertex detector of the Belle II experiment

Silicon vertex detector of the Belle II experiment

Upgrade of Belle II vertex detector with CMOS pixel technology

Status of the BELLE II Pixel Detector

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