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H− ions have now been observed in currents extracted from the CEA/Saclay ECR proton source. A pulsed, 90 degree dipole magnet has been installed 14.8 cm downstream from an ion beam extraction system designed to operate up to 10 kV. The plasma chamber can be biased by a negative or positive HV power supply and the diagnostics are grounded. The magnetic field is reduced to 200 G at the emission aperture. The measured positive hydrogen ion fractions show a large amount of H2+. A 32 wire profiler has also been installed at the dipole magnet location to analyze the total extracted beam and compare it with calculations. Profile measurements at negative extraction potential indicate an important deflection of the beam when the magnetic filter is installed. To measure a consistent electron to H− ratio, the magnetic filter has been tuned in order to avoid steering the beam off axis. Preliminary results will be reported as well as analysis of the profile. This work is supported by the European Commission under cont...

ECR Ion Sources are well known for their efficient production of Highly Charged Ions [1], and also for the production of intense proton beams [2]. Recently European laboratories have decided to join their efforts to develop and improve various plasma techniques for the production of intense beams of H−, for a future application to the European Spallation Source, and possibly for other high power accelerators. Because of its great experience and skill in ECR plasmas and ion sources, CEA has decided to develop ECR ion sources for negative ion production. At first glance, this seems to be a real challenge, as negative ion production requires a very low electron temperature, incompatible with ECR heating. We will show that this contradiction can be solved. In this article we briefly summarize the present status of Negative Ion Sources (NIS). Then we describe ECR Ion Sources and how they can be of great interest for H− production. Although this domain is still rather unexplored, some work has already been performed in the field of negative ion production with ECR plasmas. That work will be shortly summarized. Eventually promising preliminary results, obtained at CEA Saclay at 2.45 GHz, will be shown.

This is a report on the ion-ion evaporative cooling experiment achieved on Dione EBIS to improve its performance. A helium gas injection in the ionisation region through a leak valve produces a near 100% increase of the highly charged krypton ions. This method, among several others used to inject the cold ions in the containment region, was found to be the most effective for the cooling in our EBIS. This result leads us to improve Dione still more by increasing the confinement time and the electron beam intensity, the loss by ion heating being contained.

1. 1. In salt-acclimated frogs, water and urea bladder permeabilities are markedly higher than in tap water-acclimated animals. 2. 2. Intra-membrane particle aggregates (IMPA) cover an unusually large surface area of the salt-acclimated frog bladder aplcal plasma membrane. 3. 3. In saline-adapted animals, proteins extracted from the aplcal plasma membrane contain additional species of 19, 26, 31 and 53–61 kDa. These proteins might be related to the water channels contained by IMPA.

DIONE has been built and tested from 1985 to 1986 and set up on its high voltage plateform in 1987. The first accelerated beam was served to physicists in 1987 fall.Since that time, the source has been running 1500 hours as a preinjector and nuclear physics experiments, distributed in four runs of two weeks, have been performed according to the SATURNE schedule.

The fine structure of ADH-induced intramembrane particle aggregates has been studied in different tissues and under different experimental conditions. Particle aggregates similar to those previously observed in the amphibian urinary bladder and in the mammalian collecting duct were also found in the frog skin, another ADH target tissue. In the frog urinary bladder, typical aggregates were observed in the absence of glutaraldehyde fixation. Two experimental approaches were used 1) the absence of both fixative and cryoprotectant treatments and b) the absence of only glutaraldehyde treatment. In the latter case the reversal of hydrosmotic action was prevented by exposing the preparations to N-ethyl maleimide. In specimens of frog urinary bladder conventionally fixed with glutaraldehyde, two fracture levels could be observed in the aggregates, suggesting that the aggregated particles span an appreciable part of the membrane thickness.

It is now generally accepted that ADH-induced increase in water permeability in responsive epithelia is associated with the insertion of specific structures in the apical membrane of epithelial cells. Up to now, these structures have only been recognized in freeze-fractured preparations and their chemical nature is still unknown. In this study, we used the label-fracture method (Pinto da Silva and Kan, J. Cell Biol., 99, 1156-1161, 1984) to investigate the distribution of wheat germ agglutinin (WGA) on the luminal plasma membrane of freeze-fractured frog urinary bladder epithelial cells. With label-fracture, the cytochemical markers are seen superimposed with the conventional high resolution image of the E face. Label-fracture of tissue treated for 15 min with WGA and subsequently labeled with colloidal gold coated with ovomucoid showed uniform distribution of gold particles along the exoplasmic fracture face. Stereomicrographs show that the gold label is under the fracture face as it is attached to the outer surface of the membrane. Preincubation of the bladder with WGA for 3 hr induced a segregation of the intramembranous particles of the apical plasma membrane. In this condition, we observed a co-distribution of WGA-gold complexes with the segregated particles on the E face. This indicates that WGA-binding sites are located on glycoproteins which probably comprise the large intramembranous particles dispersed on the exoplasmic faces of freeze-fractured luminal membranes. In contrast, the numerous small intramembrane particles observed on P faces remained evenly distributed even after exposure to WGA and are, therefore, unrelated to WGA receptor sites. After WGA treatment, ADH still induced the formation of aggregates inside the smooth domains. A few WGA-binding sites appeared to be associated to these aggregates.