Run and slow control system of the Belle II silicon vertex detector Irmler, C.; Aihara, H.; Aziz, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
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The Belle II Silicon Vertex Detector (SVD) was installed recently and has been prepared for physics run at SuperKEKB factory, Tsukuba, Japan. For a reliable operation and data taking of the SVD, a ...sophisticated and robust run and slow control system has been implemented, which utilizes the Experimental Physics and Industrial Control System (EPICS) framework. EPICS uses client/server and publish/subscribe techniques to communicate between the various sub-systems and computers. The information exchange between the different pieces of software and computers is done by process variables (PVs). These PVs are provided by input/output controllers (IOCs), which communicate and interface with the hardware components. The Belle II SVD slow and run control comprises five groups of subsystems, which are SVD DAQ controller, Flash ADC controller, environmental monitors and interlocks, power supplies and EPICS infrastructure services. In this paper we describe the tasks and the implementation of the individual sub-systems, the interaction between them and the global Belle II run and slow control as well as the first experience from commissioning and initial operation of the SuperKEKB accelerator.
The first dedicated search for the ηc2(1D) is carried out using the decaysB+ → ηc2(1D)K+, B0 → ηc2(1D)K0S, B0 → ηc2(1D)π−K+, and B+ → ηc2(1D)π+K0Swith ηc2(1D) → hcγ. No significant signal is found. ...For the ηc2(1D) mass range between3795 and 3845 MeV/c2, the branching-fraction upper limits are determined to be B(B+ →ηc2(1D)K+) × B(ηc2(1D) → hcγ) < 3.7 × 10−5, B(B0 → ηc2(1D)K0S) × B(ηc2(1D) →hcγ) < 3.5 × 10−5, B(B0 → ηc2(1D)π−K+) × B(ηc2(1D) → hcγ) < 1.0 × 10−4, andB(B+ → ηc2(1D)π+K0S) × B(ηc2(1D) → hcγ) < 1.1 × 10−4 at 90% C. L. The analysis isbased on the 711 fb−1 data sample collected on the Υ(4S) resonance by the Belle detector,which operated at the KEKB asymmetric-energy e+e− collider.
This paper shows the hardware and the procedure utilized to test all components of the readout system (cables, FADC boards, junction boards) of the Belle II Silicon Vertex Detector after the series ...production. For the FADC board special testing hardware and firmware were designed and created to check all digital and analog inputs and outputs as well as all data interconnections on the board. The main FPGA on the FADC board generates digital signals which are converted to periodic analog differential alternating voltages up to 40 MHz on the FADC board tester, which then are fed into the analog inputs of the FADC board. Histograms and scans of the samples are recorded by using random equivalent-time sampling or sequential equivalent-time sampling, allowing to characterize the behavior of the system with a much higher bandwidth than the ADCs could do with conventional measurements. Small changes of parameters of the assembly (like using a cable of different length) lead to significant changes of the measured values, creating a sensitive testing instrument. The shapes of the distributions are analyzed and compared to references by software which then decides if a test is passed or not.
The commissioning setup of the whole readout chain, with all the final components including the final detector, has been tested in three phases. The respective graphs of the signal-to-noise ratios of the strips of a detector module and histograms of the noise development of the whole detector show very high consistency of the SVD readout system.
Performance of the Belle II Silicon Vertex Detector Tanigawa, H.; Adamczyk, K.; Aihara, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2020, Letnik:
972
Journal Article
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The Belle II experiment at the SuperKEKB collider of KEK (Japan) started recording physics data in spring 2019 with all its subdetectors installed and with the goal of accumulating 50ab−1 of e+e− ...collision events at the unprecedented instantaneous luminosity of 8×1035cm−2s−1, about 40 times larger than its predecessor. The Belle II vertex detector plays a crucial role in the broad Belle II physics program, especially for time-dependent CP measurements. It consists of two layers of DEPFET-based pixels and four layers of double-sided silicon strip detectors (SVD).
The experience gained from the first period of SVD operation can be summarized as smooth and reliable running of the detector, with high stability of noise levels and calibration parameters obtained from local calibration runs. No major problem has been experienced. The detector even survived a few serious radiation accidents in which the beam was lost due to failure in the machine focusing quadrupoles without any notable damage. The SVD performance were carefully studied with these first physics data. The SVD showed excellent hit and tracking efficiency. Moreover, cluster energy and signal to noise ratio as well as the hit time and spatial resolutions measured on data showed a fair agreement with the expected performance.
•Belle II silicon vertex detector operated during the first year of the experiment.•All sensors worked with stable and excellent hit efficiencies above 99 %.•Signal-to-noise ratios between 15 and 30, cluster time resolution better than 3 ns.•First effects of irradiation visible in leakage currents.
The first dedicated search for the ηc2(1D) is carried out using the decays B+ → ηc2(1D)K+, B0 → ηc2(1D)K$0\atop{S}$, B0 → ηc2(1D)π-K+, and B+ → ηc2(1D)π +K$0\atop{S}$ with ηc2(1D) → hcγ. No ...significant signal is found. For the ηc2(1D) mass range between 3795 and 3845 MeV/c2, the branching-fraction upper limits are determined to be B(B+ → ηc2(1D)K+) × B(ηc2(1D) → hcγ) < 3.7 × 10-5 , B(B0 → ηc2(1D)K$0\atop{S}$) × B(ηc2(1D) → hcγ) < 3.5 × 10-5, B(B0 → ηc2(1D)π-K+) × B(ηc2(1D) → hcγ) < 1.0 × 10-4, and B(B+ → ηc2(1D)π+K$0\atop{S}$) × B(ηc2(1D) → hcγ) < 1.1 × 10-4 at 90% C. L. The analysis is based on the 711 fb-1 data sample collected on the Υ(4S) resonance by the Belle detector, which operated at the KEKB asymmetric-energy e+e- collider.
Radiation absorbed doses due to intravenous administration of fluorine-18-fluorodeoxyglucose in positron emission tomography (PET) studies were estimated in normal volunteers. The time-activity ...curves were obtained for seven human organs (brain, heart, kidney, liver, lung, pancreas, and spleen) by using dynamic PET scans and for bladder content by using a single detector. These time-activity curves were used for the calculation of the cumulative activity in these organs. Absorbed doses were calculated by the MIRD method using the absorbed dose per unit of cumulated activity, "S" value, transformed for the Japanese physique and the organ masses of the Japanese reference man. The bladder wall and the heart were the organs receiving higher doses of 1.2 x 10(-1) and 4.5 x 10(-2) mGy/MBq, respectively. The brain received a dose of 2.9 x 10(-2) mGy/MBq, and other organs received doses between 1.0 x 10(-2) and 3.0 x 10(-2) mGy/MBq. The effective dose equivalent was estimated to be 2.4 x 10(-2) mSv/MBq. These results were comparable to values of absorbed doses reported by other authors on the radiation dosimetry of this radiopharmaceutical.
Commissioning of the Belle II Silicon Vertex Detector Casarosa, G.; Aihara, H.; Aziz, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
Journal Article
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The Belle II experiment at the SuperKEKB collider of KEK (Japan) will accumulate 50 ab−1 of e+e- collision data at an unprecedented instantaneous luminosity of 8⋅ 1035 cm−2s−1, about 40 times larger ...than its predecessor. The Belle II vertex detector plays a crucial role in the rich Belle II physics program, especially for time-dependent measurements. It consists of two layers of DEPFET-based pixels and four layers of double sided silicon strip sensors (SVD detector). We report here results of the standalone commissioning of the SVD and highlights from the first cosmic runs acquired in Belle II. We also report on reconstruction performances of a reduced-scale version of the SVD operated during the accelerator commissioning in 2018.
In the present article we wish to report the discovery of a novel class of ETA-selective endothelin (ET) receptor antagonists through the modification of the ETA/ETB non-selective antagonist, ...Ro47-0203 (Bosentan, 1). Replacement of the benzenesulfonamide group of 1 with a 2-phenylethenesulfonamide group gave compound 5a and resulted in improvement in ETA-selectivity. Optimization of the alkoxy side chain attached to the core pyrimidine ring yielded the 2-fluoroethoxy derivative (5n) with further improvement of ETA-selectivity. IC50=2.1 nM for ETA receptor, ETB/ETA ratio=1200. After oral administration, compound 5n inhibited the big ET-1 induced pressor response in pithed rats with a DR2 value of 2.6 mg/kg and also exhibited a potent antagonistic activity in conscious rats.
The Belle II vertex detector integration Kodyš, P.; Abudinen, F.; Ahlburg, P. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2019, Letnik:
936
Journal Article
Recenzirano
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The Belle II experiment comes with a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric e+e− collider with energies tuned to ϒ(4S) resonance s=10.588 GeV. ...The accelerator has successfully completed the first phase of commissioning in 2016 and the first electron–positron collisions in Belle II took place in April 2018. Belle II features a newly designed silicon vertex detector based on DEPFET pixel and double-sided strip layers. Currently, a subset of the vertex detector is installed (Phase 2 of the experiment). Installation of the full detector (Phase 3) will be completed by the end of 2018.
This paper describes the Phase 2 arrangement of the Belle II silicon vertex detector, with focus on the interconnection of detectors and their integration with the software framework of Belle II. Alignment issues are discussed based on detector simulations and first acquired data.
Here, we report on the first Belle search for a light CP-odd Higgs boson, A0, that decays into low mass dark matter, χ, in final states with a single photon and missing energy. We search for events ...produced via the dipion transition Υ(2S)→Υ(1S)π+π-, followed by the on-shell process Υ(1S)→γA0 with A0→χχ, or by the off-shell process Υ(1S)→γχχ. Utilizing a data sample of 157.3×106 Υ(2S) decays, we find no evidence for a signal. We set limits on the branching fractions of such processes in the mass ranges MA0 <8.97 GeV/c2 and Mχ<4.44 GeV/c2. We then use the limits on the off-shell process to set competitive limits on WIMP-nucleon scattering in the WIMP mass range below 5 GeV/c2.
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