Cucumber seedling growth under constant and fluctuating photosynthetic photon flux density (PPFD) light (CPL FPL, respectively) was examined to discuss whether plants can acclimate CPL versus FPL. The FPL created in a chamber by artificially reproducing fluctuations ground-level sunlight PPFD using phosphor-converted white LEDs. daily mean at the canopy surface photoperiod were same for grown t...

The main advantage of Bragg reflection from a multilayer mirror as a monochromator for hard X-rays, is the higher photon flux density because of the larger spectral bandpass compared with crystal lattice reflection. The main disadvantage lies in the strong modulations of the reflected beam profile. This is a major issue for micro-imaging applications, where multilayer-based monochromators are f...

Plasmas are generated in a low ionization potential gas, tetrakis(dimethylamino)ethylene (TMAE) vapor through a one-photon ionization process by an ultraviolet laser beam at a 193 nm wavelength. The TMAE plasma characteristics are studied by means of a L.angmuir probe and microwave scattering. A new method is used to measure the 193 nm ultraviolet (UV) photon absorption cross section in TMAE. I...

Photosynthesis is fundamentally driven by photon flux rather than energy flux, but not all absorbed photons yield equal amounts of photosynthesis. Thus, two measures of photosynthetically active radiation have emerged: photosynthetic photon flux (PPF), which values all photons from 400 to 700 nm equally, and yield photon flux (YPF), which weights photons in the range from 360 to 760 nm accord...

The sky photon background flux has been measured at the southern Auger site in Malargüe, Argentina, using the observatory’s fluorescence detectors (FD). The analysis is based on ADC variances of pixels not triggered by the First Level Trigger. Photon fluxes are calculated for each individual pixel at each telescope. The statistics from each night of data taking allows a study of local variation...

Photoionization has been a highly selective method for the preparation of polyatomic molecular ions [1]. VUV light, usually of low intensity, must be employed; the produced ion flux has, however, often been insufficient for many interesting appli­ cations. Classical methods have employed discharge lamps or, more recently, synchrotron radiation [2]. The former is limited to a few wavelengths a t...

Background: External beam radiation therapy is often administered to patients implanted with silicone gel breast prosthesis. The aim of this study was to investigate the influence of silicone gel breast prosthesis on photon dose distributions. In the event of recurrence, the oncologist may be forced to irradiate through the prosthetic device. To quantify the dose enhancement or reduction below ...

We present a determination of the distributions of gamma-ray photon flux – the so-called LogN–LogS relation – and photon spectral index for blazars, based on the third extragalactic source catalogue of the Fermi Gamma-ray Space Telescope’s Large Area Telescope, and considering the photon energy range from 100 MeV to 100 GeV. The data set consists of the 774 blazars in the so-called Clean sample...