Radiation tolerance of Cu(In,Ga)Se2 (CIGS) solar cells has been investigated using high-fluence proton beam irradiation for application to devices in extremely-high-radiation environment. CIGS solar cells deteriorated after high-energy proton irradiation with non-ionizing energy loss of 1 × 1016 MeV neq/cm2, however, the CIGS solar cells could generate power after high-fluence irradiation. The ideality factors increased from 1.3 to 2.0, and series resistance increased, indicating that the concentration of recombination centers increased in CIGS layers. After heat-light annealing, the conversion efficiencies gradually recovered, and the recombination centers were confirmed to be partly passivated by annealing at 90 °C. The short-circuit currents for 10-μm-thick CIGS solar cells were recovered by dark annealing in the same manner as 2-μm-thick CIGS solar cells. Dark annealing on irradiated CIGS solar cells has beneficial effects to passivate the recombination centers even using thicker CIGS layers.
The small binding energy of hypertrition leads to predictions of non-existence of bound hypernuclei for the isotriplet three-body system such as nnΛ. However, invariant mass spectroscopy at GSI reported events that may be interpreted as the bound nnΛ state. The nnΛ state was searched for by missing-mass spectroscopy via the (e, e′K+) reaction at the Jefferson Lab’s experimental Hall A. The present experiment has higher sensitivity to the nnΛ-state investigation in terms of the better precision by a factor of about three than the previous invariant mass spectroscopy. The analysis shown in this article focuses on the derivation of the reaction-cross section for the 3H(γ*, K+)X reaction. Events that were detected in an acceptance, where a Monte Carlo simulation could reproduce the data well ($|\delta p/p| < 4\%$), were analyzed to minimize the systematic uncertainty. No significant structures were observed with the acceptance cuts, and the upper limits of the production-cross section of nnΛ state were obtained to be 21 and $31~\rm {nb/sr}$ at the 90%-confidence level when theoretical predictions of ( − BΛ, Γ) = (0.25, 0.8) and (0.55, 4.7) MeV, respectively, were assumed. The cross-section result provides valuable information to examine the existence of nnΛ.
In this paper we present an overview and preparation status of a hypernulear lifetime measurement using Timing counter for Direct Lifetime measurement (TDL) and a magnetic spectrometer named neutral kaon spectrometer 2 (NKS2) at Research Center of Electron and Photon Science (ELPH), Tohoku University. We show a result of pilot experiment to check a feasibility of our experimental method and describe a plan of a next test experiment.
A high-precision hypernuclear experiment has been commissioned at the Mainz Microtron (MAMI) to determine the hypertriton Λ binding energy via decay-pion spectroscopy. The method has been successfully pioneered with 4ΛH studies in the last decade. The experiment makes use of a novel high luminosity lithium target with a length of 45mm while being only 0.75mm thick to keep momentum smearing of the decay pions low. The target-to-beam alignment as well as the observation of the deposited heat is achieved with a newly developed thermal imaging system. Together with a precise beam energy determination via the undulator light interference method a recalibration of the magnetic spectrometers will be done to obtain a statistical and systematic error of about 20 keV. The experiment started in the summer of 2022 and initial optimization studies for luminosity and data quality are presented.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.