Recent observations of the light component of the cosmic-ray spectrum have revealed unexpected features that motivate further and more precise measurements up to the highest energies. The Dark Matter Particle Explorer (DAMPE) is a satellite-based cosmic-ray experiment that is operational since December 2015, continuously collecting data on high-energy cosmic particles with very good statistics, energy resolution, and particle identification capabilities. In this work, the latest measurements of the energy spectrum of proton+helium in the energy range from 46 GeV to 316 TeV are presented. Among the most distinctive features of the spectrum, a spectral hardening at ∼600 GeV has been observed, along with a softening at ∼29 TeV measured with a 6.6σ significance. Moreover, by measuring the energy spectrum up to 316 TeV, a strong link is established between space-and ground-based experiments, also suggesting the presence of a second hardening at ∼150 TeV. * https://geant4.web.cern.ch/node/302 † https://web.ikp.kit.edu/rulrich/crmc.html

Electroluminescence (EL) and photoluminescence in both the visible and near-infrared spectral range were observed from a holmium(dibenzoylmethanato)3(bathophenanthroline) [Ho(DBM)3bath]. Five peaks at 580nm, 660nm, 980nm, 1200nm, and 1500nm, respectively, were attributed to the internal 4f electronical transitions of the Ho3+ ions. Except for the emissions of the Ho3+ ions, a broadband exciplex emission from 480nmto670nm appeared in the EL cases. The emission intensity of the exciplex at organic interface showed a tendency to saturation beyond a certain driving voltage, while the emissions of the Ho3+ ions kept increasing. This evolution of visible EL spectra was discussed in terms of the extension of the charge recombination zone. The 1500nm emission corresponding to the F55→I65 transition suggests that the Ho(DBM)3bath is a potential candidate for optical communications.

Samarium (dibenzoylmethanato)3 bathophenanthroline (Sm(DBM)3 bath) was employed as an emitting and electron transport layer in organic light emitting diodes (OLEDs), and narrow electroluminescent (EL) emissions of a Sm3+ ion were observed in the visible and near infrared (NIR) region, differing from those of the same devices with Eu3+- or Tb3+-complex EL devices with the same structure. The EL emissions of the Sm3+-devices originate from transitions from 4G5/2 to the lower respective levels of Sm3+ ions. A maximum luminance of 490 cd m−2 at 15 V and an EL efficiency of 0.6% at 0.17 mA cm−2 were obtained in the visible region, and the improved efficiency should be attributed to introducing a transitional layer between the N,N′-diphenyl-N,N′-bis(3-methylphenyl)-1,1′-diphenyl-4,4′-diamine (TPD) film and the Sm(DBM)3 bath film and the avoidance of interfacial exciplex emission in devices. Sharp emissions of Sm3+ ions in the NIR region were also observed under a lower threshold value less than 4.5 V.

Luminance-current characteristics of organic electroluminescent devices based on the europium complex of europium(dibenzoylmethanato)3 (bathophenanthroline) (Eu(DBM)3bath) have been investigated. Transient measurements were carried out to study the decay process of excited Eu3+ ions. A comparison of experimental data and theoretical calculation shows that biexcitonic quenching among the excited Eu3+ ions is an important channel in their decay process, and this quenching process is a primary cause for our observation of a rapid decrease in quantum efficiency with increasing current density. Extending the recombination zone is found to be beneficial to reducing this defective effect. The mechanism of the quenching process is also discussed.