MV Pelletron Tandem Accelerator Research Articles

Status of the AMS project at IOP Bhubaneswar

The 3 MV tandem Pelletron accelerator facility at the Ion Beam Laboratory of the Institute of Physics (IOP), Bhubaneswar is being augmented by the installation of a fast bouncer system for routine 14 C measurements. The old injector involving a single cathode SNICS source and a 45° bending magnet has been replaced by a new system consisting of a 40 cathode MC-SNICS source and a 90° analyzing bending magnet. The system is being tested for transmission. The status of the facility with test results is presented.

Trace metal distribution studies in river water by PIXE

Proton induced X-ray Emission (PIXE) has been used to measure the trace metals especially heavy metals in Chaliyar river water samples to assess the impact of pollutants from the industrial wastes. Water samples were collected in summer and rainy seasons from three different depths along the course of the river. Measurements were carried out with 2 MeV proton beam using a 3 MV tandem pelletron accelerator at Institute of Physics, Bhubaneswar. Results from the water Samples collected in both the seasons show that the concentrations of certain heavy metals like Hg, Zn and Pb are more than the prescribed limits. This is because of pollution due to industrial wastes, indicating a need for improvement in the industrial waste treatment.

ELEMENTAL ANALYSIS OF RIVER SEDIMENTS BY PIXE AND PIGE

The Chaliyar river, located in Kerala, India has shown preoccupying pollution levels, that constitute a threat to public health and the ecological system. PIXE and PIGE techniques have been employed to measure the elemental concentrations in the river sediment samples. Thick targets were prepared out of the sediment samples collected from various sites along the course of the river. The measurements were carried out using 3 MeV proton beam obtained from 3 MV Tandem pelletron accelerator at Institute of Physics, Bhubaneswar. The elemental concentrations, especially that of heavy metals, at different sites are discussed in detail. Our results show that sediments from a site where the industrial activities are high are significantly high in concentrations of heavy metals ( Cr , Ni , Cu , Zn , Hg and Pb ) than those collected from non-industrial sites. The measured values are compared with the average composition of unpolluted river sediments and other national and international river sediments.

New design of an ion source for accelerator mass spectrometry at the Lund Pelletron

The requirements for negative ion sources designed for accelerator mass spectrometry (AMS) are, e.g., a high and stable beam current, a high efficiency, a low memory effect, and a quick system for switching between different samples. For the AMS program at the Lund 3 MV Pelletron tandem accelerator a new caesium sputtering source was constructed and installed a few years ago. Some new mechanical features of the source, as well as tests of how well the requirements are fulfilled are reported.

TRACE ELEMENT ANALYSIS OF MINERAL WATER SAMPLES BY PIXE AND ICP-MS

Trace elements present in bottled mineral water have been studied by PIXE and ICP-MS. Samples from ten different brands of bottled mineral water were prepared by preconcentration techniques. Measurements were carried out using the 2 MeV proton beam obtained from 3 MV Tandem pelletron accelerator at the Institute of Physics, Bhubaneswar. Our results are compared with Indian standard packaged natural mineral water specifications, World Health Organisation (WHO) and European guidelines for drinking water standards. Concentration of aluminium was found to be more in one of the brands. In general, our results are comparable to the above standards.

A cesium-sputtering negative ion source for AMS investigations

Accelerator mass spectrometry (AMS) requires ion sources delivering intense negative ion beams of high stability. At the Lund 3 MV Pelletron tandem accelerator a new Cs-sputtering source has therefore been constructed and installed. The source is equipped with a mechanism for automatically cracking the cesium galss ampoule inside the oven when the source is evacuated. The source is also equipped with a multiple sample holder which permits on-line sample changing without disrupting the operation of the electrostatic accelerator. In order to maximise the negative ion beam current the sample holder has a mechanism for moving the sample relative to the cesium beam. By doing this the lifetime of the samples can be increased.

The dedicated accelerator-based IBA facility AGLAE at the Louvre

Abstract The 6 SDH-2 2 MV tandem Pelletron accelerator of NEC has been installed at the Louvre to characterize museum artifacts by using IBA analytical techniques: PIXE and PIGME, RBS, ERD, as well as NRA. The facility is fitted with an electrostatic energy scanning system for automatically carried out resonance depth profiling. The accelerator hall has been designed to facilitate all the possible developments of AGLAE during the next decade, including a microbeam and AMS. The hall is entirely surrounded by one meter of concrete for the protection against deuteron-induced neutrons from d-RBS, NRA and DIXE-DIGME experiments. The machine is remote-controlled and will be entirely automated. Seven ports are available on the switching magnet. Two ports are already set up, one for IBA using a multipurpose vacuum chamber and the other for extracted-beam experiments. All the beam lines have been modularly designed for well controlled, halo-free beam impacts and a clean vacuum. We shall describe the facility and discuss the VME system for the automation of the experiments, the electronic equipment, and the powerful computer system used for the fast processing of the spectra, control of the experiments, and data storage.

The 2 MV tandem pelletron accelerator of the Louvre Museum

The IBA facility of the Louvre Museum, code AGLAE, is based on the 6SDH-2 2 MV tandem Pelletron accelerator of NEC. A number of details of this machine have been specially designed with NEC to match the specific needs required for museum studies, i.e.: p, d, 3He, 4He, 15N beams from a single rf source, purely electrostatic focusing, halo-free submillimeter beam impacts, high-energy as well as low-energy operation at relatively high currents for resonance depth profiling of light nuclei including 1H, the possibility to automatize the machine operation as far as possible, development towards 14C AMS, and a microbeam extension. Special features of this machine include electrostatic steerers at the injection and electrostatic dog-leg steerers at the high-energy side, double slits at both sides of the accelerator, triplets instead of doublets for beam symmetry, turbomolecular recirculation of the stripper gas at the terminal, a new design of the stripper system itself, and a double feedback system with two capacitive pickoff plates for optimum energy spread and stability. The reasons of these special features will be explained and the characteristics of the machine as observed until now will be presented.

Search for fractionally charged particles.

An ion-source and a charge spectrometer have been built which make it possible to search in solid stable matter for particles with non-integral charge. The ion-source uses a beam of magnetically analyzed 30 keV Ar+ ions to sputter the sample in an ultra high vacuum environment. The charge spectrometer comprises a 3 MV Pelletron tandem accelerator followed by a 0.2% resolution electrostatic analysis system and a ΔE-E detector system. The entire apparatus has been constructed to be independent of mass over a mass range of 0.2 GeV/c2 to 250 GeV/c2. It is assumed that fractionally charged particle is able to bind an electron. A search has been carried out in samples of niobium and tungsten for fractionally charged particles (FCP) with fractional charge modulo 1/3. In particular, we have looked Z = N + 1/3; N = 0,1, . . . and Z = N + 2/3; N = 0,1. Upper limits have been obtained for the FCP concentration per target atom. These upper limits vary between 1 x 10-16 and 3 x 10-19 depending on the material searched and the charge state examined. Some interesting events have been seen. These are FCP candidates, but they can also be explained as improbable integrally charged events.