The rates of true and apparent photosynthesis of two unicellular green algae, one diatom and four blue-green algae were measured in buffer at pH 8.0 at subsaturating concentrations of dissolved inorganic carbon (13-27 micromolar). Initial rates of depletion from the medium of inorganic carbon and (14)C activity caused by the algae in a closed system were measured by gas chromatography and by li...

The history, present situation and prospects on electron multiplication and secondary scintillation in liquid xenon and their application to radiation detectors are shortly discussed.

An X-ray calorimeter has been used to determine the to ta l energy t ransported by bremsstrahlung beams with maximum photon energies between 18.2 and 170 Mev. The measurements from two experiments have been used to calibrate an aluminum ionization chamber for routine determinations of to ta l beam energy. The calibrations are compared with calibrations of the same chamber made with a scintillat...

The use and detection of radiotracers in organic and biological chemistry has benefitted from advances in the efficiency and sophistication of both the chromatographic and the radioactive detection techniques. As a result, the chromatographic separation of radiolabeled compounds, sometimes referred to as “radiochromatography,” is now carried out in many laboratories throughout the world. The ba...

The scientiic instrumentation on board the X-ray Astronomy Satellite BeppoSAX includes a Medium Energy Concentrator Spectrometer (MECS), operating in the energy range 1.3?10 keV, which consists of three units, each composed of a grazing incidence Mirror Unit and of a position sensitive Gas Scintillation Proportional Counter. The design and performance of the MECS instrument are here described, ...

The Oriented Scintillation Spectrometer Experiment (OSSE) on the COMPTON Gamma Ray Observatory has undertaken comprehensive observations of many galactic sources since launch in April 1991. These include investigations of binary X-ray sources, pulsars, several transient X-ray sources observed as Targets-ofOpportunity, and Nova Cygni 1992. Multiple observations of the galactic center region were...

Scintillation produced in liquid xenon by alpha particles and gamma rays has been studied as a function of applied electric field. For back scattered gamma rays with energy of about 200 keV, the number of scintillation photons was found to decrease by 64±2% with increasing field strength. Consequently, the pulse shape discrimination power between alpha particles and gamma rays is found to reduc...