Houarner, C., Boujrad, A., Tripon, M., Bezard, M., Blaizot, M., Bourgault, P., et al. (2025). NUMEXO2: a versatile digitizer for nuclear physics. J. Instrum., 20(5), T05004–21pp.
Abstract: NUMEXO2 is a 16 channels 14 bit/200 MHz digitizer and processing board initially developed for gamma-ray spectroscopy (for EXOGAM: EXOtic nuclei GAMma ray). NUMEXO2 has been gradually extended and improved as a general purpose digitizer to fulfill various needs in nuclear physics detection at GANIL. This was possible thanks to reprogrammable components like FPGAs and the optimization of different algorithms. The originality of this work compared to similar systems is that all numerical operations follow the digital data flow from ADCs, without any storage step of samples. Some details are given on digital processing of the signals, delivered by a large variety of detectors: HPGe, silicon strip detector, ionisation chamber, liquid and plastic scintillators read-out with photomultipliers, Multi Wire Proportional Counter and drift chamber. Thanks to this high versatility, the NUMEXO2 digitizer is extensively used at GANIL (Grand Acc & eacute;l & eacute;rateur National d'Ions Lourds). Some of the performances of the module are also reported.
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Soderstrom, P. A. et al, Agramunt, J., Egea, J., Gadea, A., & Huyuk, T. (2019). Neutron detection and gamma-ray suppression using artificial neural networks with the liquid scintillators BC-501A and BC-537. Nucl. Instrum. Methods Phys. Res. A, 916, 238–245.
Abstract: In this work we present a comparison between the two liquid scintillators BC-501A and BC-537 in terms of their performance regarding the pulse-shape discrimination between neutrons and gamma rays. Special emphasis is put on the application of artificial neural networks. The results show a systematically higher gamma-ray rejection ratio for BC-501A compared to BC-537 applying the commonly used charge comparison method. Using the artificial neural network approach the discrimination quality was improved to more than 95% rejection efficiency of gamma rays over the energy range 150 to 1000 keV for both BC-501A and BC-537. However, due to the larger light output of BC-501A compared to BC-537, neutrons could be identified in BC-501A using artificial neural networks down to a recoil proton energy of 800 keV compared to a recoil deuteron energy of 1200 keV for BC-537. We conclude that using artificial neural networks it is possible to obtain the same gamma-ray rejection quality from both BC-501A and BC-537 for neutrons above a low-energy threshold. This threshold is, however, lower for BC-501A, which is important for nuclear structure spectroscopy experiments of rare reaction channels where low-energy interactions dominates.
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Bottoni, S. et al, Gadea, A., & Perez-Vidal, R. M. (2025). Investigating the structure of 11B using particle-γ coincidences. Nucl. Phys. A, 1062, 123138–4pp.
Abstract: The structure of 11B was investigated at Legnaro National Laboratories of INFN using the 6Li(6Li,py) fusion-evaporation reaction. Emitted protons feeding excited states of 11B were detected by the GALTRACE silicon telescopes in coincidence with y rays measured by the GALILEO HPGe array. The level and y-decay scheme of 11B was reconstructed on an even-by-event basis by combining particle and y-ray spectroscopy techniques. In particular, the y decay from the possible near-threshold proton resonance was searched for, providing first results on its y-ray branch with a 5 sigma and 3 sigma confidence level. Results are discussed along with predictions of the Shell Model Embedded in the Continuum (SMEC).
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Capra, S., Mengoni, D., Dueñas, J. A., John, P. R., Gadea, A., Aliaga, R. J., et al. (2019). Performance of the new integrated front-end electronics of the TRACE array commissioned with an early silicon detector prototype. Nucl. Instrum. Methods Phys. Res. A, 935, 178–184.
Abstract: The spectroscopic performances of the new integrated ASIC (Application-Specific Integrated Circuit) preamplifiers for highly segmented silicon detectors have been evaluated with an early silicon detector prototype of the TRacking Array for light Charged Ejectiles (TRACE). The ASICS were mounted on a custom-designed PCB (Printed Circuit Board) and the detector plugged on it. Energy resolution tests, performed on the same detector before and after irradiation, yielded a resolution of 21 keV and 33 keV FWHM respectively. The output signals were acquired with an array of commercial 100-MHz 14-bit digitizers. The preamplifier chip is equipped with an innovative Fast-Reset device that has two functions: it reduces dramatically the dead time of the preamplifier in case of saturation (from milliseconds to microseconds) and extends the spectroscopic dynamic range of the preamplifier by more than one order of magnitude. Other key points of the device are the low noise and the wide bandwidth.
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Aliaga, R. J., Herrero-Bosch, V., Capra, S., Pullia, A., Duenas, J. A., Grassi, L., et al. (2015). Conceptual design of the TRACE detector readout using a compact, dead time-less analog memory ASIC. Nucl. Instrum. Methods Phys. Res. A, 800, 34–39.
Abstract: The new TRacking Array for light Charged particle Ejectiles (TRACE) detector system requires monitorization and sampling of all pulses in a large number of channels with very strict space and power consumption restrictions for the front-end electronics and cabling, Its readout system is to be based on analog memory ASICs with 64 channels each that sample a 1 μs window of the waveform of any valid pulses at 200 MHz while discarding any other signals and are read out at 50 MHz with external ADC digitization. For this purpose, a new, compact analog memory architecture is described that allows pulse capture with zero dead time in any channel while vastly reducing the total number of storage cells, particularly for large amounts of input channels. This is accomplished by partitioning the typical Switched Capacitor Array structure into two pipelined, asymmetric stages and introducing FIFO queue-like control circuitry for captured data, achieving total independence between the capture and readout operations.
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