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The experiment BESIII, running at the accelerator BEPCII in Beijing (P.R.C.), is going to be updated with the replacement of the Inner Drift Chamber with a Cylindrical triple-GEM Inner Tracker (CGEM-IT). In the R&D stage, two standalone C++ codes were implemented: GTS (Garfield-based Triple-GEM Simulator), for digitization and tuning of simulated data to the experimental ones, and GRAAL (GEM Reconstruction And Analysis Library), for the reconstruction and analysis of the experimental events collected in testbeams. GTS simulates the triple-GEM response to the particle passage, treating each stage separately: ionization, GEM properties, gas mixture, magnetic field and finally the induction of the signal on the anode. The necessary information was extracted by GARFIELD++ simulations, parametrized and used as input in GTS. This speeds up the simulation, since GTS performs only samplings instead of the full digitization chain. The simulated events were reconstructed with the same procedure used for experimental data and tuning factors were evaluated to obtain a satisfactory match. GRAAL is used in the analysis of the testbeam experimental data. It provides several levels of reconstruction: from the cluster formation, gathering contiguous firing strips, to the spatial position and the signal time reconstruciton. Two algorithms are used: the charge centroid and the micro-TPC, which exploit the charge deposition on the strips and the time information. Also a merging of the two algorithms is available to efficiently weight the two outcomes and obtain the best estimate of the spatial coordinate. Moreover, GRAAL performs tracking and alignment. Both codes are going to be made available also for other MPGDs simulation and reconstruction.

Triple-GEM detectors are a well known technology in high energy physics. In order to have a complete understanding of their behavior, in parallel with on beam testing, a Monte Carlo code has to be developed to simulate their response to the passage of particles. The software must take into account all the physical processes involved from the primary ionization up to the signal formation, e.g. the avalanche multiplication and the effect of the diffusion on the electrons. In the case of gas detectors, existing software such as Garfield already perform a very detailed simulation but are CPU time consuming. A description of a reliable but faster simulation is presented here: it uses a parametric description of the variables of interest obtained by suitable preliminary Garfield simulations and tuned to the test beam data. It can reproduce the real values of the charge measured by the strip, needed to reconstruct the position with the Charge Centroid method. In addition, particular attention was put to the simulation of the timing information, which permits to apply also the micro-Time Projection Chamber position reconstruction, for the first time on a triple-GEM. A comparison between simulation and experimental values of some sentinel variables in different conditions of magnetic field, high voltage settings and incident angle will be shown.

Performance of triple GEM prototypes in strong magnetic field has been evaluated by means of a muon beam at the H4 line of the SPS test area at CERN. Data have been reconstructed and analyzed offline with two reconstruction methods: the charge centroid and the micro-Time-Projection-Chamber exploiting the charge and the time measurement respectively. Depending on the combination of the particle incident angle and magnetic filed, there's always one of the two algorithms achieving a spatial resolution of 100–120 μm.

We study the hadronic decays of to the final states and , using an annihilation data sample of 567 pb-1 taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays and with statistical significance of and , respectively. Normalizing to the reference decays and , we obtain the ratios of the branching fractions and to be and , respectively. The upper limits at the 90% confidence level are set to be and . Using BESIII measurements of the branching fractions of the reference decays, we determine % ( % ( is consistent with the previous measurement, and the branching fraction of is measured for the first time.

Studies of $e^+e^- \to D_s^+ \overline{D}{}^{(*)0}K^-$ and the $P$-wave charmed-strange mesons are performed based on an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 567 pb$^{-1}$ collected with the BESIII detector at $\sqrt{s}= 4.600$ GeV. The processes of $e^+e^-\to D_s^+ \overline{D}{*}^{0} K^-$ and $D_s^+ \overline{D}{}^{0} K^-$ are observed for the first time and are found to be dominated by the modes $D_s^+ D_{s1}(2536)^-$ and $D_s^+ D^*_{s2}(2573)^-$, respectively. The Born cross sections are measured to be $\sigma^{B}(e^+e^-\to D_s^+ \overline{D}{*}^{0} K^-) = (10.1\pm2.3\pm0.8) pb$ and $\sigma^{B}(e^+e^-\to D_s^+ \overline{D}{}^{0} K^-) = (19.4\pm2.3\pm1.6) pb$, and the products of Born cross section and the decay branching fraction are measured to be $\sigma^{B}(e^+e^-\to D_s^+D_{s1}(2536)^- + c.c.)\cdot\mathcal{B}(D_{s1}(2536)^- \to \overline{D}{*}^{0} K^-) = (7.5 \pm 1.8 \pm 0.7) pb$ and $\sigma^{B}(e^+e^-\to D_s^+ D^*_{s2}(2573)^- + c.c.)\cdot\mathcal{B}(D^*_{s2}(2573)^- \to \overline{D}{}^{0} K^-) = (19.7 \pm 2.9 \pm 2.0) pb$. For the $D_{s1}(2536)^-$ and $D^*_{s2}(2573)^-$ mesons, the masses and widths are measured to be $M(D_{s1}(2536)^-) = (2537.7 \pm 0.5 \pm 3.1)~MeV/c^2,$ $ \Gamma(D_{s1}(2536)^-)) = (1.7\pm 1.2 \pm 0.6)~\rm MeV,$ and $M(D^*_{s2}(2573)^-) = (2570.7\pm 2.0 \pm 1.7)~MeV/c^2,$ $\Gamma(D^*_{s2}(2573)^-) = (17.2 \pm 3.6 \pm 1.1)~\rm MeV.$ The spin-parity of the $D^*_{s2}(2573)^-$ meson is determined to be $J^P=2^{+}$. In addition, the process $e^+e^-\to D_s^+ \overline{D}{}^{(*)0} K^-$ are searched for using the data samples taken at four (two) center-of-mass energies between 4.416 (4.527) and 4.575 GeV, and upper limits at the $90\%$ confidence level on the cross sections are determined.

Positron emission tomography is one of the most mature techniques for monitoring the particles range in hadron therapy, aiming to reduce treatment uncertainties and therefore the extent of safety margins in the treatment plan. In-beam PET monitoring has been already performed using inter-spill and post-irradiation data, i.e. while the particle beam is off or paused. The full beam acquisition procedure is commonly discarded because the particle spills abruptly increase the random coincidence rates and therefore the image noise. This is because random coincidences cannot be separated by annihilation photons originating from radioactive decays and cannot be corrected with standard random coincidence techniques due to the time correlation of the beam-induced background with the ion beam microstructure. The aim of this paper is to provide a new method to recover in-spill data to improve the images obtained with full-beam PET acquisitions. This is done by estimating the temporal microstructure of the beam and thus selecting input PET events that are less likely to be random ones. The PET detector we used was the one developed within the INSIDE project and tested at the CNAO synchrotron-based facility. The data were taken on a PMMA phantom irradiated with 72 MeV proton pencil beams. The obtained results confirm the possibility of improving the acquired PET data without any external signal coming from the synchrotron or ad hoc detectors.

PANDA is a key experiment of the future FAIR facility and the Micro Vertex Detector (MVD) is the innermost part of its tracking system. PASTA (PAnda STrip ASIC) is the readout chip for the strip part of the MVD. The chip is designed to provide high resolution timestamp and charge information with the Time over Threshold (ToT) technique. Its architecture is based on Time to Digital Converters with analog interpolators, with a time bin width of 50 ps. The chip implements Single Event Upset (SEU) protection techniques for its digital parts. A first full-size prototype with 64 channels was produced in a commercial 110 nm CMOS technology and the first characterizations of the prototype were performed.

This paper describes a readout ASIC prototype designed by CHIPIX65 project, part of RD53, for a pixel detector at HL-LHC . A 64 × 64 matrix of 50 × 50 μ m2 pixels is realised. A digital architecture has been developed, with particle efficiency above 99.9% at 3 GHz/cm2 pixel rate, 1 MHz trigger rate with 12.5 μ s latency. Two analog front end designs, one synchronous and one asynchronous, are implemented. Charge is measured with 5-bit precision and the analog dead-time is below 1%. IP-blocks (DAC, ADC, BandGap, SER, sLVS-TX/RX) and very front ends are silicon proven, irradiated to 600-800Mrad.

We present a readout and digitization ASIC featuring low-noise and low-power for time-of flight (TOF) applications using SiPMs. The circuit is designed in standard CMOS 110 nm technology, has 64 independent channels and is optimized for time-of-flight measurement in Positron Emission Tomography (TOF-PET). The input amplifier is a low impedance current conveyor based on a regulated common-gate topology. Each channel has quad-buffered analogue interpolation TDCs (time binning 20 ps) and charge integration ADCs with linear response at full scale (1500 pC). The signal amplitude can also be derived from the measurement of time-over-threshold (ToT). Simulation results show that for a single photo-electron signal with charge 200 (550) fC generated by a SiPM with 320 pF capacitance the circuit has 24 (30) dB SNR, 75(39) ps r.m.s. resolution, and 4(8) mW power consumption. The event rate is 600 kHz per channel, with up to 2 MHz dark counts rejection.

The ANDA (Antiproton Annihilation at Darmstadt) experiment foresees many detectors for tracking, particle identification and calorimetry. Among them, the innermost is the MVD (Micro Vertex Detector) responsible for a precise tracking and the reconstruction of secondary vertices. This detector will be built from both hybrid pixel (two inner barrels and six forward disks) and double-sided micro strip (two outer barrels and outer rim of the last two disks) silicon sensors. A time-based approach has been chosen for the readout ASIC of the strip sensors. The PASTA (ANDA Strip ASIC) chip aims at high resolution time-stamping and charge information through the Time over Threshold (ToT) technique. It benefits from a Time to Digital Converter (TDC) allowing a time bin width down to 50 ps. The analog front-end was designed to serve both n-type and p-type strips and the performed simulations show remarkable performances in terms of linearity and electronic noise. The TDC consists of an analog interpolator, a digital local controller, and a digital global controller as the common back-end for all of the 64 channels.

The upgrade of the silicon pixel sensors for the HL-LHC experiments requires the development of new readout integrated circuits due to unprecedented radiation levels, very high hit rates and increased pixel granularity. The design of a very compact, low power, low threshold analog very front-end in CMOS 65 nm technology is described. It contains a synchronous comparator which uses an offset compensation technique based on storing the offset in output. The latch can be turned into a local oscillator using an asynchronous logic feedback loop to implement a fast time-over-threshold counting. This design has been submitted and the measurement results are presented.

The Gigatracker (GTK) is a hybrid silicon pixel detector developed for NA62, an experiment studying ultra-rare kaon decays at the CERN SPS. The main characteristics are a time-tagging resoluion of 150ps, with low material budget per station (0.5% X0) and a fluence comparable to the one expected for the inner trackers of LHC detectors in 10 years of operation. To compensate the time-walk, two read-out architectures have been designed and produced. The first architecture is based on a Constant Fraction Discriminator (CFD) followed by an on-pixel Time-to-Digital-Converter (TDC). The second architecture is based on a on-pixel group shared TDC. The GTK system developments are described: the integration steps (assembly and cooling) and the results obtained from the prototypes fabricated for the two read-out architectures.

The ANDA (antiProton ANnihilation at DArmstadt) experiment will study the strong interaction in annihilation reactions between an antiproton beam and a stationary gas jet target. The detector will comprise different sub-detectors for tracking, particle identification and calorimetry. The Micro-Vertex Detector (MVD) as the innermost part of the tracking system will allow precise tracking and detection of secondary vertices. For the readout of the double-sided silicon strip sensors a custom-made ASIC is being developed, employing the Time-over-Threshold (ToT) technique for digitization and utilize time-to-digital converters (TDC) to provide a high-precision time stamp of the hit. A custom-made Module Data Concentrator ASIC (MDC) will multiplex the data of all front-ends of one sensor towards the CERN-developed GBT chip set (GigaBit Transceiver). The MicroTCA-based MVD Multiplexer Board (MMB) at the off-detector site will receive and concentrate the data from the GBT links and transfer it to FPGA-based compute nodes for global event building.

A beam test of different prototypes of single chip hybrid pixel assembly, aimed for the ANDA Micro-Vertex-Detector, was performed at the T9 facility of CERN-PS in August 2012. Their data acquisition was operated with continuous readout as foreseen in the experiment. In this paper the experimental set-up of the test and the data analysis are described and then the results are discussed.

For the EndoTOFPET-US experiment, the TOFPET ASIC has been developed as a front-end chip to read out data from silicon photomultipliers (SiPM) [1]. It introduces a time of flight information into the measurement of a PET scanner and hence reduces radiation exposure of the patient [2]. The chip is designed to work with a high event rate up to 100 kHz and a time resolution of 50 ps LSB. Using two threshold levels, it can measure the leading edge of the event pulse precisely while successfully suppressing dark counts from the SiPM. This also enables a time over threshold determination, leading to a charge measurement of the signal's pulse. The same, time-based concept is chosen for the PASTA chip used in the PANDA experiment. This high-energy particle detector contains sub-systems for specific measurement goals. The innermost of these is the Micro Vertex Detector, a silicon-based tracking system. The PASTA chip's approach is much like the TOFPET ASIC with some differences. The most significant ones are a changed amplifying part for different input signals as well as protection for radiation effects of the high-radiation environment. Apart from that, the simple and general concept combined with a small area and low power consumption support the choice for using this approach.

A 64-channel ASIC for Time-of-Flight Positron Emission Tomography (TOF PET) imaging has been designed and simulated. The circuit is optimized for the readout of signals pro- duced by the scintillation of a L(Y)SO crystal optically coupled to a silicon photomultiplier (SiPM). Developed in the framework of the EndoTOFPET-US collaboration (1), the ASIC is integrated in the external PET plate and performs timing, digitization and data transmission for 511 keV and lower-energy events due to Compton scattering. Multi-event buffering capability allows event rates up to 100 kHz per channel. The channel cell includes a low input impedance low-noise current conveyor and two trans-impedance amplifier branches separately optimized for energy and time resolution. Two voltage mode discriminators generate respectively a fast trigger for accurate timing and a signal for time-over-threshold calcu- lation, used for charge measurement. The digitization of these signals is done by two low-power TDCs, providing coarse and fine time stamps that are saved into a local register and later managed by a global controller, which builds-up the 40-bit event data and runs the interface with the data acquisition back-end. Running at 160 MHz the chip yields a 50 ps time binning and dissipates u 7 mW per channel (simulated for 40 kHz event rate p/channel) for high capacitance photodetectors (9 mm 2 active area Silicon Photomultiplier with 320 pF terminal capacitance). The minimum SNR of 23.5 dB expected with this capacitance should allow triggering on the first photoelectron to achieve the envisaged timing performance for a TOF-PET system.

The readout architecture for the silicon pixel detector of the PANDA MVD (Micro Vertex Detector) is presented. The pixel detector has to provide timing, position and energy information on a event-driven base, since no trigger signal is foreseen. The readout system is based on a custom ASIC, named ToPiX, directly connected to the GBT (GigaBit Transceiver) optical transceiver. A reduced size prototype with most of the main functionalities has been designed and tested. The ASIC has been bonded to a sensor based on the epitaxial technology and tested on a beam test. TID (Total Ionizing Dose) tests on the ToPiX prototype have been performed.

The GigaBit Laser Driver (GBLD) is a radiation tolerant ASIC which is part of the GigaBit Transceiver (GBT) chipset. It is aimed to drive both edge emitting and VCSEL laser diodes at a data rate in excess of 5 Gb/s. The GBLD can provide a modulation current up to 24 mA and a bias current up to 43 mA. Pre- and de-emphasis functions are implemented to compensate for high external capacitive loads and asymmetric laser response. The chip is designed in a 130 nm CMOS technology and is powered by a single 2.5 V supply.

The ToPiX ASIC is a custom development for the hybrid pixel sensors of the PANDA experiment Micro Vertex Detector. The ASIC will provide both the time and amplitude informations (via the Time over Threshold technique) of the incoming particle. ToPiX will consist of a matrix of 116 Oe 110 cells with a pixel size of 100 Oe 100 mum(2), the column readout logic and two 311 Mbit/s serializers. A reduced scale prototype in CMOS 0.13 mum has been designed and tested. The prototype includes eight columns with the full cell analogue and digital circuitry and the end of column readout.

The GigaBit Transceiver (GBT) project aims at the design of a radiation tolerant chip set for high speed optical data transmission. The chipset includes the GigaBit Laser Driver (GBLD), a radiation tolerant ASIC designed in a standard CMOS 130 nm technology. The GBLD is a laser driver designed to work to up to 5 Gb/s and capable to drive both Vertical Cavity Surface Emitting Lasers (VCSELs) and Edge Emitting Lasers (EELs). The GBLD can provide a modulation current up to 24 mA and a bias current up to 43 mA with the pre-emphasis function to compensate for external capacitive load.

The silicon tracker of the NA62 experiment requires the measurement of the particles arrival time with a resolution better than 200 ps rms and a spatial resolution of 300 μm. A time measurement technique based on a Time to Amplitude Converter has been implemented in an ASIC in order to prove the possibility to integrate a TDC with resolution better than 200 ps in a pixel cell. Time-walk problem has been addressed with the use of the Constant Fraction Discriminator technique. The ASIC has been designed in a CMOS 0.13 μm technology with single event upset protection of the digital logic.

The electronic readout architecture for the silicon pixel detector of the PANDA Micro Vertex Detector is presented. The pixels will provide occurrence time, position and energy information; moreover, no trigger signal is foreseen, thus leading to a huge amount of data to be transmitted. The foreseen readout system is based on a custom ASIC development, named ToPix, which provides time information via a time stamp synchronous with the 155.5MHz global clock signal and energy information via the Time Over Threshold technique. High speed serial links and early electrical to optical conversion are adopted to reduce the amount of cables and material.