Abstract Positron-emitting tracer imaging systems (PETIS) apply the principles of positron emission tomography to plant research, enabling non-destructive, real-time visualization of substance distribution in living plants. However, the conventional PETIS instruments using bismuth germanate (BGO) scintillator arrays and position-sensitive photomultiplier tubes have limited spatial resolution 1.6–2.1 mm full width at half maximum (FWHM), and the relatively long decay time of BGO restricts the coincidence timing resolution (CTR) and count-rate performance. In addition, the thickness of the scintillator array can introduce parallax errors due to depth-of-interaction ambiguity. To enable submillimeter-scale imaging of fine structures like leaf veins, we developed a compact, high-resolution prototype PETIS unit tailored for thin plant organs. The prototype features two face-to-face detector modules separated by 2 cm. Each module consists of a finely segmented cerium-doped gadolinium aluminium gallium garnet scintillator array (1 × 1 × 1 and 1.5 × 1.5 × 1 mm 3 crystals), a 1-mm light guide, an 8 × 8 silicon photomultiplier array, and a TOFPET2 application-specific integrated circuit. The 1-mm-thick scintillator design drastically reduces depth-of-interaction parallax errors while optimizing count-rate capability. The performance was evaluated using a 22 Na point source. The system achieved 511 keV energy resolutions of 11–13 % FWHM. Reconstructed images demonstrated spatial resolutions of 1.1–1.2 mm FWHM, significantly outperforming the conventional PETIS instruments. The CTR reached 773 ± 16 ps with an effective coincidence detection efficiency of 6.54 × 10 -5 . These fundamental performance results demonstrate the strong potential of the compact unit for localized, high-resolution plant transport studies.
Abstract The coming ALICE Inner Tracking System (ITS) upgrade uses MAPS (Monolithic Active Pixel Sensors) with multiple integrated 10.24-Gbps transmitters. The NKF7 chip is a proto transmitter serializing a 16-bit input into a 10.24-Gbps output. Connecting NKF7 16-data inputs to an FPGA allows for the generation of arbitrary patterns. A PRBS7 pattern results (at the end of the ITS3 FPC cable) into open eyes at 5.12 Gbps (Bit Error Ratio < 10 -15 ) but closes at 10.24 Gbps (BER > 10 -9 @ V DD = 1.45 V). Reducing V DD further degrades BER and increases jitter which is also seen in chip simulations after adding GND and V DD bond wire inductance. This inductance gives on-die supply noise which will be mitigated in future chips by integrating on-die regulators. Irradiation with 32-MeV protons gives σ SEU ≈ 10 -12 cm 2 and NKF7 withstands a TID > 10 Mrad.
Abstract The original compact gas-dynamic ion-beam extractor/buncher module is proposed here as a new instrument for low-energy ion-beam manipulation. In order to enhance the quality of pulsed cold ion beams extracted from the two cryogenic stopping cells at FAIR (i.e., the one currently used in the FRS and the one under development for the Super-FRS at FAIR), it is hereby proposed that this module be utilised as a substitute for the extensively employed linear radiofrequency quadrupole (RFQ) technique. The proposed apparatus facilitates the extraction and fast bunching of approximately 100% ions into a vacuum by means of a short stack of thin cylindrical electrodes positioned on the axis behind the extraction RF carpet nozzle. The implementation of the proposal will enable the achievement of low emittance values for short-pulsed ion beams in a wide mass range, as demonstrated by detailed gas-dynamic and ion trajectory Monte Carlo simulations. The results of these simulations are presented and discussed.
Abstract Plasma characteristics of a compact Penning ion source are investigated using a triple Langmuir probe. Electron temperature and number density are estimated for continuous and pulsed mode of discharge at various range of pressure and anode voltage. The spatial and temporal behavior of plasma is analyzed to study the effect of operating parameters on the discharge stability of the ion source. The dynamics of electron temperature and number density are studied under varying discharge conditions. The decline in electron temperature with increasing pressure and enhancement with anode voltage are recorded. Electron density increases with injected gas pressure and acceleration potential. The maximum value of 4.4 × 10 10 electron/cm 3 and 5.5 × 10 12 electron/cm 3 have been measured in continuous and pulsed mode of discharge respectively. These results are essential to optimize Penning ion source for research and industrial application where stable, dense and low-temperature plasmas are required.
Abstract Ultrashort electron bunches are a key requirement for a broad range of modern accelerator applications, including pump-probe experiments, advanced radiation sources, and plasma-based acceleration schemes. Their generation is essential for accessing ultrafast temporal scales and increasing peak current. Here, we investigate a self-compression scheme for producing high-brightness, femtosecond electron bunches at low energy (< 100 MeV) in compact accelerators (< 10 m). The method uses a wiggler-chicane configuration in which CSR-induced energy modulation in the wiggler is converted into high-current spikes by a downstream chicane. As a case study, we assess its feasibility for TEX, which hosts a C-band photoinjector facility currently under commissioning at INFN-LNF. Numerical estimates and beam dynamics simulations (ASTRA, Elegant, TStep) are used to evaluate the achievable bunch lengths for different photoinjector operating modes and compression strategies. Building on previous studies, this work also investigates collective effects at low energies, showing that space-charge forces enhance the longitudinal compression factor. Overall, the results highlight the potential for producing high-brightness, femtosecond electron bunches within strict spatial constraints.
