The last decades brought impressive progress in synthesizing and studying properties of nuclides located very far from the beta stability line. Among the most fundamental properties of such exotic nuclides, the ones usually established first are the half-life, possible radioactive decay modes, and their relative probabilities. When approaching limits of nuclear stability, new decay modes set in. First, beta decays are accompanied by emission of nucleons from highly excited states of daughter nuclei. Second, when the nucleon separation energy becomes negative, nucleons start being emitted from the ground state. A review of the decay modes occurring close to the limits of stability is presented. The experimental methods used to produce, identify, and detect new species and their radiation are discussed. The current theoretical understanding of these decay processes is reviewed. The theoretical description of the most recently discovered and most complex radioactive process---the two-proton radioactivity---is discussed in more detail.

Radioactive decays at limits of nuclear stability

The SERSE source [P. Ludwig et al., Rev. Sci. Instrum. 69, 4082 (1998), and references therein] is a superconducting electron cyclotron resonance (ECR) ion source, operating at the Laboratori Nazionali del Sud in Catania since 1998; it is currently used as the main injector for the K-800 superconducting cyclotron. Its high magnetic field provides a high plasma confinement and large currents of highly charged ions, as compared to conventional sources. It can efficiently operate at the microwave frequency of 14 and 18 GHz [S. Gammino and G. Ciavola, Rev. Sci. Instrum. 71, 631 (2000); S. Gammino et al., ibid.70, 3577 (1999)] and has been used as a test bench for injection at 28 GHz. High-frequency operation is expected to create a higher plasma density, thus resulting in larger currents of multiply charged ions. In this article, we report the first operation of an ECR ion source at 28 GHz by using a gyrotron. The gyrotron itself and the waveguide line are described, along with the operational results (in xen...

Operation of the SERSE superconducting electron cyclotron resonance ion source at 28 GHz

The suitable source for the production of intense beams for high power accelerators must obey to the request of high brightness, stability, and reliability. The 2.45 GHz off-resonance microwave discharge sources are the ideal device to generate the requested beams, as they produce multimilliampere beams of protons, deuterons, and monocharged ions, remaining stable for several weeks without maintenance. A description of different technical designs will be given, analyzing their strength, and weakness, with regard to the extraction system and low energy beam transport line, as the presence of beam halo is detrimental for the accelerator.

Review on high current 2.45 GHz electron cyclotron resonance sources (invited).

Electron cyclotron resonance (ECR) ion sources are scientific instruments particularly useful for physics: they are extensively used in atomic, nuclear, and high energy physics, for the production of multicharged beams. Moreover, these sources are also of fundamental interest for plasma physics, because of the very particular properties of the ECR plasma. This article describes the state of the art on the physics of the ECR plasma related to multiply charged ion sources. In Sec. I, we describe the general aspects of ECR ion sources. Physics related to the electrons is presented in Sec. II: we discuss there the problems of heating and confinement. In Sec. III, the problem of ion production and confinement is presented. A numerical code is presented, and some particular and important effects, specific to ECR ion sources, are shown in Sec. IV. Eventually, in Sec. V, technological aspects of ECR are presented and different types of sources are shown.

Electron cyclotron resonance plasmas and electron cyclotron resonance ion sources: Physics and technology (invited)

A hybrid nuclear reactor that is operable to produce a medical isotope includes an ion source operable to produce an ion beam from a gas, a target chamber including a target that interacts with the ion beam to produce neutrons, and an activation cell positioned proximate the target chamber and including a parent material that interacts with the neutrons to produce the medical isotope via a fission reaction. An attenuator is positioned proximate the activation cell and selected to maintain the fission reaction at a subcritical level, a reflector is positioned proximate the target chamber and selected to reflect neutrons toward the activation cell, and a moderator substantially surrounds the activation cell, the attenuator, and the reflector.

Device and method for producing medical isotopes

The superconducting electron cyclotron resonance ion source SERSE of INFN-Laboratori Nazionali del Sud has been recently upgraded with an 18 GHz generator which takes the place of the 14.5 GHz generator, used up to now. In order to further extend the validation of high B mode to higher frequency, some comparative tests have also been carried out, aimed at understanding the role of the magnetic field and frequency on the ion yield at higher levels than were ever done before. The results at the frequencies of 14.5 and 18 GHz are compared and the trend already observed elsewhere is here confirmed. Preliminary observations of the “two frequency heating” have contributed to increase further the currents of the highest charge states.

18 GHz upgrading of the superconducting electron cyclotron resonance ion source SERSE

The Trasco Intense Proton Source (TRIPS) was installed at INFN-LNS in May 2000 and has been fully operational since the Fall of 2000; now the source fulfills all the requirements of the TRASCO (Trasmutazione Scorie) project. The proton beam intensity easily exceeds 40 mA at the operating voltage of 80 kV. A set of emittance measurements was carried out for different source conditions and confirmed the simulations performed with the AXCEL code: in all the cases the rms normalized emittance is well lower than the value required for the injection into the RFQ (0.2 π mm mrad); the results will be shown and discussed. Finally a beam reliability of 99.8% has been found during a long run test lasting over 142 h.

Status of the Trasco Intense Proton Source and emittance measurements

A full set of measurements of the magnetic field has been carried out to define a different design of the TRASCO Intense Proton Source (TRIPS) magnetic system, based on permanent magnets, in order to increase the reliability of the source. The two coils of the source generate a maximum field of 150 mT and the optimum field was determined around 95 mT. The OPERA-3D package was used to simulate the magnetic field and a new magnetic system was designed as a combination of three rings of NdFeB magnets and soft iron. The high voltage insulation has been completely modified, in order to avoid any electronics at 80 kV voltage. The description of the magnetic measurements and the comparison with the simulations are presented, along with the mechanical design of the new version permanent magnet TRIPS (PM-TRIPS) and the new design of the extraction system. Finally the modification of the low energy beam transfer line (LEBT), which now includes a 30° bending magnet, will be outlined, with special regard to the accelerator availability improvement which can be obtained with the installation of two PM-TRIPS sources or more on the LEBT.

A version of the Trasco Intense Proton Source optimized for accelerator driven system purposes

The TRASCO intense proton source (TRIPS) has been installed at INFN-LNS in May 2000 and is now operational. The paper describes the design of the source along with the first results obtained and the next developments. The source has been able to deliver more than 20 mA of protons from a 5 mm hole at 65 kV extraction voltage, largely above the minimum requested current density. The optimisation of the source is under way, with special care to the reliability and satisfactory results have been achieved.

/pdf/first-beam-from-the-trasco-intense-proton-source-trips-at-b6q64sysa6.pdf

First beam from the TRASCO intense proton source (TRIPS) at INFN-LNS

In order to get a correct bunching of the tandem beams to be injected into the K-800 superconducting cyclotron at LNS and to improve further the transmission inside the tandem, the construction of a new injector providing 450 keV negative ions became necessary. The project, funded in 1990, is now complete. The commissioning of the 450 kV injector has been carried out paying particular attention to some technical problems: 1) the presence of two different sources, which permits to switch easily from one source to the other, has required to double all the hardware, except for the analyzing magnet and for the gas box, in order to be effective in reducing downtimes for maintenance: 2) the reduction of the electrical noise, which disturbs the computer control system; 3) the management of 79 analogic parameters and 110 digital parameters, which has been performed in an environment where the classical control system via insulated bars fails because of the high potential gradient (10 kV/in), one of the highest ever obtained in conditioned air environment for injectors. The main features of the 450 kV injector will be summarized. The main details of the commissioning with the platform performances will be presented and some details of ion optics will be given.

Operational experience with the 450 kV injector for the superconducting cyclotron

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

F. Chines

Author Tools

Chat about Author