Abstract Populations of pluripotent stem cells were isolated from bone marrow, synovial fluid, adult dental pulp, and exfoliated deciduous teeth and their multipotentiality properties compared. ...Osteogenic, chondrogenic, adipogenic, and neurogenic differentiation potentials were examined. Bone marrow mesenchymal stem cells (BMMSCs) and synovial fluid-derived cells (SFCs) showed the highest levels of osteogenesis as expressed by alkaline phosphatase (ALP) activity (0.54 ± 0.094 U/mg protein and 0.57 ± 0.039 U/mg protein, respectively; P = 0.60) and by osteocalcin (BGLAP; determined by real-time RT-PCR). SFCs showed the highest levels of chondrogenesis as expressed by ALP activity (1.75 ± 0.097 U/mg protein) and of COL2A1 and COL10A1 by real-time PCR. In terms of adipogenesis, lipid vesicles were observed in the BMMSCs and SFCs. Dental pulp stem cells (DPSCs) and stem cells from human exfoliated deciduous teeth (SHED) exhibited neurogenesis potential, as shown by increases in expression of class III β-tubulin (TUBB3) and microtubule-associated protein 2 (MAP2) on RT-PCR. Variability was found in the differentiation potential corresponding to the tendency of the original tissue to differentiate. It is suggested that the cell type should be selected depending on the regenerative treatment regimen.
We have developed a dedicated front-end electronics board for a high-pressure xenon gas time projection chamber for a neutrinoless double-beta decay search. The ionization signal is read out by ...detecting electroluminescence photons with silicon photomultipliers (SiPMs). The board reads out the signal from 56 SiPMs and records the waveforms at 5 MS/s with a wide dynamic range up to 4000 photons/200 ns. The SiPM bias voltages are provided by the board. Fine adjustment of the bias voltage for each channel is realized while keeping the dc coupling readout constant, which is indispensable for readout of microsecond-long pulses or at high rate environment. Additional analog-to-digital converters (ADCs) measure one photon-equivalent dark current for calibration and monitoring of the SiPM. The obtained performance satisfies the requirement for a neutrinoless double-beta decay search.
Time-to-digital converters (TDCs) are used in various fields, including high-energy physics. One advantage of implementing TDCs in field-programmable gate arrays (FPGAs) is the flexibility on the ...modification of the logics, which is useful to cope with the changes in the experimental conditions. Recent FPGAs make it possible to implement TDCs with a time resolution less than 10 ps. On the other hand, various drift chambers require a time resolution of O(0.1) ns, and a simple and easy-to-implement TDC is useful for a robust operation. Herein an eight-channel TDC with a variable bin size down to 0.28 ns is implemented in a Xilinx Kintex-7 FPGA and tested. The TDC is based on a multisampling scheme with quad phase clocks synchronised with an external reference clock. Calibration of the bin size is unnecessary if a stable reference clock is available, which is common in high-energy physics experiments. Depending on the channel, the standard deviation of the differential nonlinearity for a 0.28 ns bin size is 0.13–0.31. The performance has a negligible dependence on the temperature. The power consumption and the potential to extend the number of channels are also discussed.
An experiment to measure an invariant mass of <inline-formula> <tex-math notation="LaTeX">\phi </tex-math></inline-formula> mesons in nuclear medium is planned as the J-PARC E16 experiment. A trigger ...merging module (TRG-MRG) has been developed to detect leading-edges from 256 channels of discriminator-output signals and transmit those serialized hit data to trigger decision module with four optical links. The result of the test shows enough performance of the TRG-MRG as 1-ns time-to-digital converter (TDC) and data multiplexer with four 6.25 Gb/s transceivers.
A high-intensity pulsed muon beam is becoming available at the at the Japan Proton Accelerator Research Complex (J-PARC). Many experiments to study fundamental physics using this high-intensity muon ...beam are proposed. An experiment to measure the muon magnetic moment anomaly (g−2) and the muon electric dipole moment (EDM) is one of these experiments and it requires a tracking detector for positrons from muon decay. Fine segmentation is required in a detector to tolerate the high rate of positrons. The time resolution is required to be much better than the muon anomalous spin precession period while a buffer depth of a front-end electronics needs to be much longer than the accelerated muon lifetime. Requirements of this detector also meet requirements of a measurement of the muonium hyperfine structure interval at the J-PARC and another experiment to measure the proton charge radius at Tohoku University. We have developed a single-sided silicon strip sensor with a 190 μm pitch, a front-end electronics with a sampling rate of 200 MHz and a buffer memory depth of 8192, and a data acquisition system based on DAQ-Middleware for the J-PARC muon g−2/EDM experiment. We have fabricated detector modules consisting of this sensor and the front-end electronics. Performance of fabricated detector modules was evaluated at a laboratory and a beam test using the positron beam at Tohoku University. The detector is confirmed to satisfy all requirements of the experiments except for the time walk, which will be solved by the next version of a front-end electronics.
At the Belle II experiment, Aerogel RICH is used as the particle identification device that covers the forward end-cap part of the Belle II detector. We develop the readout system of Hybrid Avalanche ...Photo Detectors that are used as the photon sensors of the Aerogel RICH. We present overview of the readout system, and report the status of the mass production toward the Belle II experiment.
Precise measurements of polarization patterns in cosmic microwave background (CMB) provide deep knowledge about the begin of the Universe. The GroundBIRD experiment aims to measure the CMB ...polarization by using microwave kinetic inductance detector (MKID) arrays. The MKID is suited to multiplexing. One of our requirements is a MUX factor (the number of readout channels for a single wire pair) of at least 100. If we make frequency combs of the MKIDs with 2-MHz spacing, a bandwidth of 200 MHz satisfies 100 MUX. The analog electronics must consist of an analog-to-digital converter (ADC), digital-to-analog converter (DAC), and local oscillator. We developed our own analog electronics board “
RHEA
.” Two outputs/inputs of DAC/ADC with a 200-MHz clock provide an effective bandwidth of 200 MHz. The RHEA allows us to measure both the amplitude and phase responses of each MKID simultaneously. These data are continuously sampled at a high rate (e.g., 1 kSPS) and with no dead time. We achieved 12 and 14 bits resolution for ADC and DAC, respectively. This corresponds to achieve that our electronics achieved low noise: 1/1000 compared with the detector noise. We also achieved low power consumption compared with that of other electronics development for other experiments. Another important feature is that the board is completely separated from the digital part. Each user can choose their preferred field-programmable array. With the combination of the Kintex-7 evaluation kit from Xilinx, we demonstrated readout of MKID response.
We have developed a silicon avalanche-photodiode (Si-APD) linear array detector to be used for time-resolved measurements in pulsed synchrotron X-ray experiments. The Si-APD linear array consists of ...64 pixels 100×200μm2, with a pixel pitch of 150μm and a depletion depth of 10μm. The nanosecond response and high counting rate of the Si-APD are very valuable for time-resolved X-ray diffraction experiments using pulsed synchrotron radiation. A detector system that can resolve successive X-ray pulses within a short interval of 2ns would be very efficient for recording the intensity and position of X-ray diffraction patterns within a nanosecond period. A prototype detector system equipped with an ultrafast application-specific integrated circuit, field-programmable gate arrays and network processor boards was fabricated. It allowed a high count-rate of >107cps per channel with a synchrotron X-ray beam; however, the time resolution was limited to 10ns. The detector successfully recorded small-angle X-ray scattering by scanning the detector position.
We developed a new positron detector system called Kalliope, which is based on multi-pixel avalanch photo-diode (m-APD), application specific integrated circuit (ASIC), field programmable gated array ...(FPGA) and ethernet-based SiTCP data transfer technology. We have manufactured a general-purpose spectrometer for muon spin relaxation (μSR) measurements, employing 40 Kalliope units (1280 channels of scintillators) installed in a 0.4 T longitudinal-field magnet. The spectrometer has been placed at D1 experimental area of J- PARC Muon Science Establishment (MUSE). Since February of 2014, the spectrometer has been used for the user programs of MUSE after a short commissioning period of one week. The data accumulation rate of the new spectrometer is 180 million positron events per hour (after taking the coincidence of two scintillators of telescopes) from a 20×20 mm sample for double-pulsed incoming muons.
The present time-to-digital converter (TDC) chips for the monitored drift tube (MDT) chambers at the ATLAS experiment will be replaced with new ones for the High-Luminosity LHC, expected to begin ...operation in 2026. The design and the performance of a 24 channel TDC with a variable time binning of down to 0.28 nsec based on a Xilinx Kintex-7 field programmable gate array are reported. The time measurement is provided by a multisampling scheme with quad phase clocks synchronized with an external reference clock. The differential and integral nonlinearities have been measured to be less than half of the time binning. The temperature dependence on the performance is observed to be small. In conclusion the obtained performance of the time measurement is sufficiently high for the use with MDT chambers.
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