J. Palinkas

Imaging of ECR plasmas with a pinhole x-ray camera

X-ray plasma images were made at the 14.5 GHz electron cyclotron resonance ion source of ATOMKI using a pinhole and a high resolution CCD camera. This method has good spatial resolution as well as the capability of postprocessed energy filtering of the images. During the measurements low and high charge state Ar, Xe, and Fe plasmas were produced with simultaneous beam extraction. Full-size and selected region images were recorded and analyzed. Full-size x-ray images show the spatial positions of different sources of x rays (bremsstrahlung, characteristic lines of plasma and wall ions) within low-charged ECRIS plasmas. Images of selected plasma regions (extraction slit, magnet pole, magnet gap) offer a better understanding of the effect of important tuning parameters (bias disk voltage, gas mixing, microwave power, magnetic field strength, etc.) commonly used to produce highly charged plasmas and beams.

Relative intensity of the Kβ5 X-ray line

Abstract The relative intensity of the Kβ5 (K-MIV,V) X-ray line as a function of the atomic number of the emitting elements is very strongly enhanced around Z = 24 (chromium) relative to predictions of the single-particle model for this electric dipole (E1) forbidden transition. The enhancement is attributed to solid state or chemical effects. The Kβ5 transition can be E1-allowed because in chemical compounds the outermost 3d level forms the valence shells, while in metals it becomes a broad band. The intensity of this line can therefore vary with the chemical state. We have determined the K β 5 K β 1 intensity ratio that results from proton impact on Ca, Ti and Cr, and we have collected the experimental data available in the literature. The influence of the sharp increase in the Kβ5 intensity on the K β K α intensity ratio and on X-ray analytical methods (e.g. proton induced X-ray emission, electron probe microanalysis, etc.) is discussed.

The new ECR ion source of the ATOMKI: A tool to generate highly charged heavy ion plasma and beam

Abstract Between 1993 and 1996 a 14 GHz electron cyclotron resonance (ECR) ion source has been designed and built in the ATOMKI. The ion source is aimed for the production of highly charged heavy ion beams from a wide range of the elements. One of the most important planned applications in the near future is its usage for low energy ion-atom collisions. This ion source is the first ECR ion source in Hungary and in Middle-Eastern Europe as well. The first plasma was successfully generated in February 1996 and the first extracted beam is expected in the fall of the year. This paper briefly reviews the history and progress of the ECR program and shows the ECR ion source itself. The results of some indirect plasma measurements (X-ray spectra) are shown and discussed.

Fullerenes in electron cyclotron resonance ion sources

Fullerene plasmas and beams have been produced in our electron cyclotron resonance ion sources (ECRIS) originally designed for other purposes. The ATOMKI-ECRIS is a traditional ion source with solenoid mirror coils to generate highly charged ions. The variable frequencies NIRS-KEI-1 and NIRS-KEI-2 are ECR ion sources built from permanent magnets and specialized for the production of carbon beams. The paper summarizes the experiments and results obtained by these facilities with fullerenes. Continuous effort has been made to get the highest C60 beam intensities. Surprisingly, the best result was obtained by moving the C60 oven deep inside the plasma chamber, very close to the resonance zone. Record intensity singly and doubly charged fullerene beams were obtained (600 and 1600nA, respectively) at lower C60 material consumption. Fullerene derivatives were also produced. We mixed fullerenes with other plasmas (N, Fe) with the aim of making new materials. Nitrogen encapsulated fullerenes (mass: 720+14=734) we...

A particle detector for energetic ions

A fast ion detector based on secondary electron emission from an aluminium surface is described. The secondary electrons are accelerated by 1.2 kV and detected by two microchannel plates in cascade configuration. Applying channel plates to the secondary electrons leads to the same detector efficiency as with the channeltron but at a much higher counting rate. The efficiency of the detector for 150 keV protons was measured as a counting rate of 0.8 at 1 MHz.

Status and special features of the Atomki ECR ion source

The ECR ion source has been operating in ATOMKI (Debrecen) since 1996. During the past 15 years lots of minor and numerous major technical modifications have been carried out on the ECRIS. Many of these changes aimed the increasing of beams charge, intensity, and the widening of the ion choice. Another group of the modifications were performed to develop special, non-standard operation modes or to produce peculiar plasmas and beams.

Investigation of the projectile atomic number dependence of the L-subshell ionization

Abstract Relative L-subshell ionization cross sections have been measured using a series of ions at a fixed collision velocity in order to study the projectile nuclear charge dependence. Thin Sm, Er, and Au targets were bombarded by 2 H + , 4 He + , 12 C + , and 14 N + ions MeV u impact energy. The cross sections were normalized to the data obtained by deuterons. The experimental results have been compared with calculations in the perturbed stationary state approximations with Coulomb deflection, binding and relativistic corrections included (CPSSR) as well as with the recent second order calculations. Particularly large discrepancies have been found for the L 2 subshell comparing the CPSSR results with the measured values. These discrepancies have been reduced significantly by the inclusion of the second order effects.

Transverse Energy Production in {sup 208}Pb+Pb Collisions at 158 GeV per Nucleon

Author(s): Margetis, S.; Alber, T.; Appelshauser, H.; Bachler, J.; Bartke, J.; Bialkowska, H.; Bieser, F.; Bloomer, M.A.; Blyth, C.O.; Bock, R.; Bormann, C.; Brady, F.P.; Brockmann, R.; Buncic, P.; Caines, H.L.; Cebra, D.; Chan, P.; Cooper, G.E.; Cramer, J.G.; Cramer, P.B.; Csato, P.; Derado, I.; Dunn, J.; Eckardt, V.; Eckhardt, F.; Euler, S.; Ferguson, M.I.; Fischer, H.G.; Fodor, Z.; Foka, P.; Freund, P.; Fuchs, M.; Gal, J.; Gasdzicki, M.; Gladysz, E.; Grebieszkow, J.; Gunther, J.; Harris, J.W.; Heck, W.; Hegyi, S.; Hill, L.A.; Huang, I.; Howe, M.A.; Igo, G.; Irmscher, D.; Jacobs, P.; Jones, P.G.; Kadija, K.; Kecskemeti, J.; Kowalski, M.; Kuhmichel, A.; Lsdiuk, B.; Margetis, S.; Mitchell, J.W.; Mock, A.; Nelson, J.M.; Odyniec, G.J.; Palinkas, J.; Palla, G.; Panagiotou, A.D.; Petridis, A.; Piper, A.; Poskanzer, A.M.; Prindle, D.J.; Puhlhofer, F.; Rauch, W.; Renfordt, R.; Retyk, W.; Ritter, Hans G.; Rohrich, D.; Rudolph, H.; Runge, K.; Sandoval, A.; Sann, H.; Schafer, E.; Schmitz, N.; Schonfelder, S.; Seyboth, P.; Seyerlein, J.; Sikler, F.; Skrzypczak, E.; Stock, R.; Stroebele, H.; Szentpetery, I.; Sziklai, J.

The Coulomb deflection effect on the L3-subshell alignment in low-velocity proton impact ionisation

The A2 alignment parameter of the L3 subshell of gold has been determined by measuring the angular distribution of the Ll/Lgamma intensity ratio following proton impact ionisation in the 0.25-0.60 MeV energy range. The experimental results make it clear that the minimum of the alignment parameter at low energies found earlier for He+ impact also exists in the case of proton impact ionisation.

Projectile energy dependence of the contributions of different mechanisms to cusp electron production in He+ → Ar collisions☆

Abstract The energy spectra of cusp electrons from He + → Ar collisions have been measured in coincidence with the outgoing charge state selected He 0,1+,2+ projectiles in the 18.75–75 keV/u energy range. The electron capture to the continuum (ECC), electron loss to the continuum (ELC), and transfer ionization (TI) reaction channels have been identified. In the energy range studied ECC decreases from 86% to 80% and ELC increases strongly from 2.2% to 19.4% with increasing energy. At 18.75 keV/u TI contributes about 12% to the total cusp electron yield whereas at 75 keV/u this fraction decreases to 1.2%. A strong target gas pressure dependence was found for the TI fraction.