Belle II Technical Design Report

The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.Comment: Edited by: Z. Dole\v{z}al and S. Un

Infrastructure for Detector Research and Development towards the International Linear Collider

The EUDET-project was launched to create an infrastructure for developing and testing new and advanced detector technologies to be used at a future linear collider. The aim was to make possible experimentation and analysis of data for institutes, which otherwise could not be realized due to lack of resources. The infrastructure comprised an analysis and software network, and instrumentation infrastructures for tracking detectors as well as for calorimetry.Comment: 54 pages, 48 picture

Belle II Vertex Detector Performance

The Belle II experiment at the SuperKEKB accelerator (KEK, Tsukuba, Japan) collected its first e+e− collision data in the spring 2019. The aim of accumulating a 50 times larger data sample than Belle at KEKB, a first generation B-Factory, presents substantial challenges to both the collider and the detector, requiring not only state-of-the-art hardware, but also modern software algorithms for tracking and alignment. The broad physics program requires excellent performance of the vertex detector, which is composed of two layers of DEPFET pixels and four layers of double sided-strip sensors. In this contribution, an overview of the vertex detector of Belle II and our methods to ensure its optimal performance, are described, and the first results and experiences from the first physics run are presented

Characterization and optimization of a thin direct electron detector for fast imaging applications

Direct electron detectors are increasingly used to explore the dynamics of macromolecules in real space and real time using transmission electron microscopy. The purpose of this work is to optimize the most suitable detector configuration of a thin silicon detector by Monte Carlo Simulations. Several simulations were performed to achieve an advanced detector geometry that reduces significantly the background signal due to backscattered electrons resulting in an enhanced imaging performance of the detector. Utilizing DEPFET (DEpleted P-channel Field Effect Transistor) technology and the novel ideas for the optimized detector geometry, a unique direct hit electron detector is currently being produced

DEPFET active pixel detectors for a future linear e+e−e^{+}e^{-} collider

The DEPFET collaboration develops highly granular, ultra-transparent active pixel detectors for high-performance vertex reconstruction at future collider experiments. The characterization of detector prototypes has proven that the key principle, the integration of a first amplification stage in a detector-grade sensor material, can provide a comfortable signal to noise ratio of over 40 for a sensor thickness of 50-75 μm. ASICs have been designed and produced to operate a DEPFET pixel detector with the required read-out speed. A complete detector concept is being developed, including solutions for mechanical support, cooling, and services. In this paper, the status of the DEPFET R & D project is reviewed in the light of the requirements of the vertex detector at a future linear e+e- collider

Operational Experience and Performance of the Belle II Pixel Detector

The Belle II experiment at the super KEK B factory (SuperKEKB) started its physics operation with the full detector setup in March 2019, and it aims at collecting 50 ab$^{−1}$ of $e^+e^−$ collision data. The vertex detector (VXD) of Belle II contains a 4-layer silicon vertex detector (SVD) using double sided silicon strips and an inner 2-layer pixel detector (PXD) that is based on the depleted P-channel Field Effect Transistor (DEPFET) technology. The signal generation and amplification are combined in pixels with a minimum pitch of 55 × 50 µm$^2$. The sensors are thinned down to 75 µm, and each module has interconnects and ASICs integrated on the sensor with silicon frames for mechanical support. This approach led to a material budget of around 0.21% X$_0$ per layer including the cooling structure in the acceptance region. The PXD has an integration time of around 20 µs, a signal-to-noise ratio of around 50 and a detecting efficiency of better than 99%. Its two layers are arranged at the radii of 14 and 22 mm around the interaction point, and an impact parameter resolution of better than 15 µm has been achieved. Due to its close proximity to the beam line and its sensitivity to few-keV photons, the PXD also plays an important role in background studies

DEPFET pixel detector in the Belle II experiment

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