No Arabic abstract
This chapter provides an overview of the basic requirements for ion sources designed and operated in radioactive ion beam facilities. The facilities where these sources are operated exploit the isotope separation online (ISOL) technique, in which a target is combined with an ion source to maximize the secondary beam intensity and chemical element selectivity. Three main classes of sources are operated, namely surface-type ion sources, arc discharge-type ion sources, and finally radio-frequency-heated plasma-type ion sources.
We report on updates to the accelerator controls for the Neutralized Drift Compression Experiment II, a pulsed induction-type accelerator for heavy ions. The control infrastructure is built around a LabVIEW interface combined with an Apache Cassandra backend for data archiving. Recent upgrades added the storing and retrieving of device settings into the database, as well as ZeroMQ as a message broker that replaces LabVIEWs shared variables. Converting to ZeroMQ also allows easy access via other programming languages, such as Python.
This chapter describes the basic principles, design features and characteristics of microwave discharge ion sources. A suitable source for the production of intense beams for high-power accelerators must satisfy the requirements of high brightness, stability and reliability. The 2.45 GHz off-resonance microwave discharge sources are ideal devices to generate the required beams, as they produce multimilliampere beams of protons, deuterons and singly charged ions. A description of different technical designs will be given, analysing their performance, with particular attention being paid to the quality of the beam, especially in terms of its emittance.
Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.
The radioactive contamination of ZnWO4 crystal scintillators has been measured deep underground at the Gran Sasso National Laboratory (LNGS) of the INFN in Italy with a total exposure 3197 kg x h. Monte Carlo simulation, time-amplitude and pulse-shape analyses of the data have been applied to estimate the radioactive contamination of the ZnWO4 samples. One of the ZnWO4 crystals has also been tested by ultra-low background gamma spectrometry. The radioactive contaminations of the ZnWO4 samples do not exceed 0.002 -- 0.8 mBq/kg (depending on the radionuclide), the total alpha activity is in the range: 0.2 - 2 mBq/kg. Particular radioactivity, beta active 65Zn and alpha active 180W, has been detected. The effect of the re-crystallization on the radiopurity of the ZnWO4 crystal has been studied. The radioactive contamination of samples of the ceramic details of the set-ups used in the crystals growth has been checked by low background gamma spectrometry. A project scheme on further improvement of the radiopurity level of the ZnWO4 crystal scintillators is briefly addressed.
The three-dimensional NAM-ECRIS model is applied for studying the metal ion production in the DECRIS-PM Electron Cyclotron Resonance Ion Source. Experimentally measured extracted ion currents are accurately reproduced with the model. Parameters of the injection of metal vapors into the source are optimized. It is found that the axial injection of the highly directional fluxes allows increasing the extracted ion currents of the highly charged calcium ions by factor of 1.5. The reason for the gain in the currents is formation of internal barrier for the ions inside the plasma, which increase the ion extraction and production efficiency. Benefits of injecting the singly-charged calcium ions instead of atoms are discussed.