The high-energy/high-intensity laser facility PHELIX of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt,Germany,has been in operation since 2008.Here,we review the current system performance,which ...The high-energy/high-intensity laser facility PHELIX of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt,Germany,has been in operation since 2008.Here,we review the current system performance,which is the result of continuous development and further improvement.Through its versatile frontend architecture,PHELIX can be operated in both long-and short-pulse modes,corresponding to ns-pulses with up to 1 kJ pulse energy and sub-ps,200 J pulses,respectively.In the short-pulse mode,the excellent temporal contrast and the control over the wavefront make PHELIX an ideal driver for secondary sources of high-energy ions,neutrons,electrons and X-rays.The long-pulse mode is mainly used for plasma heating,which can then be probed by the heavy-ion beam of the linear accelerator of GSI.In addition,PHELIX can now be used to generate X-rays for studying exotic states of matter created by heavy-ion heating using the ion beam of the heavy-ion synchrotron of GSI.展开更多
A new search for two-neutrino double-beta(2νββ)decay of^(136)Xe to the 0+1 excited state of 136Ba is performed with the full EXO-200 dataset.A deep learning-based convolutional neural network is used to discriminat...A new search for two-neutrino double-beta(2νββ)decay of^(136)Xe to the 0+1 excited state of 136Ba is performed with the full EXO-200 dataset.A deep learning-based convolutional neural network is used to discriminate signal from background events.Signal detection efficiency is increased relative to previous searches by EXO-200 by more than a factor of two.With the addition of the Phase II dataset taken with an upgraded detector,the median 90%confidence level half-life sensitivity of 2νββdecay to the 0+1 state of 136Ba is 2.9×10^(24)yr using a total^(136)Xe exposure of 234.1 kg yr.No statistically significant evidence for 2νββdecay to the 0^(+)_(1)state is observed,leading to a lower limit of T2ν1/2(0^(+)→0^(+)_(1))>1.4×10^(24)yr at 90%confidence level,improved by 70%relative to the current world's best constraint.展开更多
基金funding from the European Union’s Horizon 2020 research and innovation programme via the transnational access and joint research activity programmes of Laserlab(grant agreement Nos.871124 and 654148)funding from the European Union’s HORIZON-INFRA-2022-TECH-01 call under grant agreement number 101095207(THRILL)financed via the BMBF Er UM-APPA collaborative research scheme(contract numbers 05P19RFFA1-Goethe-Universität Frankfurt,05P21RDFA2-Technische Universität Darmstadt,05P19SJFA1 and 05P21SJFA2-Friedrich-Schiller Universität Jena)。
文摘The high-energy/high-intensity laser facility PHELIX of the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt,Germany,has been in operation since 2008.Here,we review the current system performance,which is the result of continuous development and further improvement.Through its versatile frontend architecture,PHELIX can be operated in both long-and short-pulse modes,corresponding to ns-pulses with up to 1 kJ pulse energy and sub-ps,200 J pulses,respectively.In the short-pulse mode,the excellent temporal contrast and the control over the wavefront make PHELIX an ideal driver for secondary sources of high-energy ions,neutrons,electrons and X-rays.The long-pulse mode is mainly used for plasma heating,which can then be probed by the heavy-ion beam of the linear accelerator of GSI.In addition,PHELIX can now be used to generate X-rays for studying exotic states of matter created by heavy-ion heating using the ion beam of the heavy-ion synchrotron of GSI.
文摘A new search for two-neutrino double-beta(2νββ)decay of^(136)Xe to the 0+1 excited state of 136Ba is performed with the full EXO-200 dataset.A deep learning-based convolutional neural network is used to discriminate signal from background events.Signal detection efficiency is increased relative to previous searches by EXO-200 by more than a factor of two.With the addition of the Phase II dataset taken with an upgraded detector,the median 90%confidence level half-life sensitivity of 2νββdecay to the 0+1 state of 136Ba is 2.9×10^(24)yr using a total^(136)Xe exposure of 234.1 kg yr.No statistically significant evidence for 2νββdecay to the 0^(+)_(1)state is observed,leading to a lower limit of T2ν1/2(0^(+)→0^(+)_(1))>1.4×10^(24)yr at 90%confidence level,improved by 70%relative to the current world's best constraint.
