P. Y. Nabhiraj

Variable Energy Cyclotron Centre | VECC · Physics Group

A 2.45 GHz microwave ion source is designed, developed and commissioned at VECC. A proton beam current of 12mA at 75 keV was extracted and transported from the ion source [1]. An experimental study of parametric variations on the performance of ion source was performed. In order to establish a theoretical correlation with the experimental results a...

Recently in VECC, metal ion beam was generated and delivered from one of the two 14.45GHz ECR ion sources using MIVOC facility and has been successfully accelerated by K130, room temperature cyclotron. Although being a simple method, MIVOC has several disadvantages like contaminating the ECR chamber and poor transport efficiency. To overcome these...

An indigenously developed 14.45 GHz ECR ion source is injecting heavy ion beams into K-130 cyclotron at VECC. Waveguide break is required to provide the isolation between the microwave system and plasma chamber. The waveguide break is constituted by two waveguides interrupted by an insulator. It should withstand the applied high voltage between the...

PVA/HAp based bionanocomposite coatings (PHAp) are prepared by the microwave-assisted deposition technique. The surface of the coatings is modified using low energy (90 keV) argon (Ar⁹⁺) ions with various fluences 1×10¹⁴, 1×10¹⁵ and 1×10¹⁶ ions/cm². A significant reduction in crystallite size attained at lower fluence (1×10¹⁴ ions/cm²) with a varia...

Pure V and V-4Cr-4Ti has been irradiated with Ar⁹⁺ion at 0.4, 2.3, 8.4 and 23 dpa. GIXRD was carried at two different incident angles i.e. at 0.2° and 0.45° using Synchrotron radiation. The XRD data were analyzed to determine the variation of microstructural parameters like domain size and microstrain as a function of dose by modified Rietveld tech...

पिछले कुछ दशकों में बायोमास, कोयला और कचरे से ऊर्जा के उत्पादन के लिए प्लाज़्मा तकनीक का उपयोग पूरे विश्व में बहुत तेजी से प्रचलित हुआ है| प्लाज़्मा तकनीक के उपयोग में बढ़ोतरी मुख्यत: इसकी उच्च दक्षता , बेहतर पर्यावरण और आर्थिक पहलुओं के कारण हुई है| प्रायोगिक और सैद्धांतिक शोध द्वारा यह भी स्पष्ट किया जा चुका है, कि ऊर्जा उत्पादन के लिए प्लाज़्मा...

Polymer-based zinc ions incorporated HAp nanocomposite coatings (ZHAp) on titanium substrate are synthesized by wet-chemical route and assisted by microwave irradiation. The surface of the nanocomposite coatings was modified by low energy (90 keV) argon (Ar⁹⁺) ions with various fluences 1 × 10¹⁴, 1 × 10¹⁵ and 1 × 10¹⁶ ions/cm². A significant reduct...

Under upgradation of cyclotron systems, an 18 GHz superconducting ECR ion source (SCECRIS) is being designed and developed at VECC. Design of the magnetic system of SCECRIS had been completed and initiatives are taken for its fabrication and testing. The magnetic system consists of four axial superconducting solenoid coils and a permanent magnet ba...

The time structure of high energy ion beam is one of the crucial parameters for several nuclear physics experiments. In order to obtain a narrow time structure for the experiments it should be measured and optimized as per the experiment requirements. Moreover, if the beam is injected through axial injection system into the cyclotron, an ion beam b...

Open volume defect profiles have been obtained in He, O and (He + O) ion implanted silicon crystal 〈1 0 0〉 using slow positron beam measurements. The p-type Si samples have been implanted with He (30 keV), O (120 keV) and both the ions [He (30 keV) + O(120 keV)] with the dose of 1 × 10¹⁵ and 1 × 10¹⁷ ions/cm². The average range of these ions in Si...

Samples of Ti-modified stainless steel alloy have been irradiated using 315 KeV Ar⁹⁺ ion to varying doses resulting in high dpa levels from 100 to 400. The variation of the secondary phase present in the sample as a function of irradiation dose has been characterised using Grazing Incidence X-ray Diffraction measurements. Energy Dispersive X-ray ma...

The effective dispersion of Graphene Nanosheet (GNS) as reinforcement was studied with various morphology of Copper (Cu) powder as matrix. High energy milling was used for modifying the morphology of the Cu powders. The Cu powder with Spherical and dentric shape was used in this study. Using high energy milling both the powders were milled for 8 h...

Composites obtained by powder metallurgy from a mixture of copper powders and graphene nanosheets are studied. The response surface methodology is used to design the regression dependence of the HRC hardness of the composites on the temperature, the duration of the sintering, and the sintering heating rate. Adequacy of the model for predicting the...

In this article an equivalent circuit approach based on transmission line theory is proposed to design the waveguide break for 14.45 GHz ECR ion source. The parameters of three designs of waveguide break are first obtained using equivalent circuit approach. These designs are then simulated using a commercial FEM software ANSYS HFSS. Furthermore, al...

Response of Zr–2.5 wt.% Nb alloy pressure tube, used in PHWR nuclear reactors, to 315 keV Ar⁹⁺ ion irradiation at room temperature was investigated in the fluence range of 3.1 × 10¹⁵–4.17 × 10¹⁶ Ar⁹⁺ cm⁻². Changes in microstructural parameters, viz., the size of coherently scattering domains, microstrain and dislocation density, upon irradiation we...

Copper (Cu) composite reinforced with graphene nanosheet (GNS) is obtained by powder metallurgy technique. The microstructure and mechanical properties were investigated based on the Cu composite reinforced with various GNS content (0, 1, and 2 wt.%). The characterization is carried out through Raman spectra (RS), Fourier transform infrared (FTIR),...

In order to accelerate heavy ions from K-130 cyclotron, an axial injection line consisting of 14.5 GHz ECR ion source and beam transport line is commissioned recently. ECR ion source and a short beam transport line is indigenously designed and developed. ECR ion source uses room temperature solenoid coils to produce magnetic fields of ~ 1.2 Tesla i...

A General purpose, 4 channels, ARM based vacuum gauge control system which can be used with cold cathode gauges of any make is developed. Here S3C2440 based mini2440 arm board and ADS1115, 16bit ADC are used. All the four channels can have independent limits that can be set for generating alarms and provide interlocks through potential free contact...

Recently the indigenously developed 14.45 GHz ECR ion source is installed and commissioned for heavy ion beam injection into K130 room temperature cyclotron. A PC based remote control and monitoring system is developed for ease of operation and operator safety. The ECR system consists of several high current magnet power supplies such as ECR coil s...

The waveguide break is a key component of an electron cyclotron resonance ion source. It is required to provide the isolation between the microwave system and plasma chamber, because the plasma chamber is biased to high voltage for the extraction of ion beam and microwave generator is kept at the ground potential. The waveguide break is constituted...

An axial injection system comprising of a 14.5 GHz ECR-3 ion source along with a low energy beam transport line is recently commissioned with K-130 cyclotron. A double gap gridded rf buncher is designed and installed in the axial injection line to improve the injection efficiency of the cyclotron. The physics design of the buncher is optimized usin...

The microstructural parameters such as domain size and microstrain have been estimated from Grazing Incidence X-ray Diffraction (GIXRD) data for Ar⁹⁺ irradiated Zr-1Nb-1Sn-0.1Fe sample as a function of dpa (dose). Detail studies using X-ray Diffraction Line Profile Analysis (XRDLPA) from GIXRD data has been carried out to characterize the microstru...

The effective dispersion of Graphene Nanosheet (GNS) as reinforcement was studied with various morphology of Copper (Cu) powder as matrix. High energy milling was used for modifying the morphology of the Cu powders. The Cu powder with Spherical and dentric shape was used in this study. Using high energy milling both the powders were milled for 8h a...

Low-energy Argon ions from electron cyclotron resonance ion source were bombarded on polycarbonate films. The interaction of ions with the surface of the material was studied by using X-ray diffraction analysis, Fourier transform infrared spectroscopy, thermo-gravimetric analysis and atomic force microscopy. The study reveals that the surface rough...

In this investigation, Copper (Cu)/ Graphene Nanao Sheet (GNS) composites were prepared by using the powder metallurgy technique. The microstructure and the mechanical properties were studied and characterised by Fourier transform infrared spectroscopy, X-ray diffraction, High resolution Scanning Electron Microscopy (SEM) and Transmission Electron...

Low energy Argon (Ar+) and Hydrogen (H+) ions were made to fall on the surface of Polycarbonate (PC) films. The depth profile calculations of ions on the material were carried out using Stopping and Range of Ions in Matter (SRIM-2008) code. The influence of bombarded ions with regard to the optical, structural and chemical properties was studied us...

Novel Cellulose (Cel) reinforced polyvinyl alcohol (PVA)-Silica (Si) composite which has good stability and in vitro degradation was prepared by lyophilization technique and implanted using N 3+ ions of energy 24 keV in the fluences of 1×10 15 , 5×10 15 and 1×10 16 ions/cm 2 . SEM analysis revealed the formation of microstructures, and improved...

The present study focuses on understanding the effect of Ar ion irradiation at room temperature on Cr rich Ni-Cr alloy. The alloy is irradiated with Ar⁹⁺ ions (energy 315 keV) for total dose varying from 9.3 × 10¹⁴ to 2.3 × 10¹⁶ ion/cm². The changes in the microstructure of the irradiated samples have been characterized by depth dependent Doppler b...

Titania aerogels were synthesized by sol–gel route followed by ambient pressure subcritical drying technique. The aerogels synthesized in the present work possess a maximum surface area of 252 m2/g. The pore size distribution is between 2 and 30 nm which confirms their mesoporosity. The oxygen plasma treatment on titania aerogel thin films improved...

Zr-2.5 Nballoy is used as a pressure tube material in pressurized heavy water reactor (PHWR). It is one of the most critical component which decides the lifespan of the reactor. The in-reactor degrading phenomenon of prime concern is dimensional changes caused by irradiation induced creep and growth processes. The present study aims to understand t...

Layered materials and sp2 hybridized structures like graphite and hexagonal-boron nitride (h-BN) have been subjected to electron cyclotron resonance (ECR) ion beam implantation of proton and argon ions at different fluences and studied primarily employing slow positron beam technique using positron annihilation Doppler broadening spectroscopy (DBS)...

Copper oxide thin film of about 260–280 nm thickness was deposited using pulsed laser deposition (PLD) on glass substrate at 350 °C and post depositional sample treatment was performed by ion implantation with 50 keV N5+ ion beam with varying particle fluence. Amorphous copper oxide thin film deposited at 80 mTorr partial pressure of oxygen was tra...

During the last two decades, focused ion beam (FIB) technology has been used as a tool in highly demanding applications in the field of nanotechnology such as repair of photolithography masks, repair and modification of integrated circuits, TEM sample preparation, selective implantation, resist exposure etc. The technology of using FIBs for nano/mi...

A 2.45 GHz microwave ion source and a low energy beam transport system have been developed to study the high intensity proton beam injection into a 10 MeV, 5 mA compact cyclotron. We have extracted proton beam more than 10 mA at 80 kV as measured by the DCCT after the extraction and a well collimated beam of 7 mA (through 1 cm × 1 cm slit) at the f...

VECC is planning to develop a rare ion beam facility called ANURIBANU stands for "Atom in Sanskrit".1 (Advanced National facility for Unstable and Rare Isotope Beams) at the upcoming new campus at New Town in Kolkata. ANURIB aims to attract a wide user community in nuclear physics, nuclear-astrophysics, material science and biology and will provide...

Radioactive ion beams (RIB) have been recently accelerated for the first time at the VECC-RIB facility. Beams of 14O (71 s), 42K (12.4 h), 43K (22 h) and 41Ar (1.8 h) have been produced by bombarding 1 atm nitrogen and argon gas targets with 1 micro-ampere proton and alpha particle beams from the K130 cyclotron. Radioactive atoms were transported 1...

The 14.45GHz Electron Cyclotron Resonance (ECR) ion source generates and injects the ion beam of different species and different charge states in super conducting cyclotron (SCC). The vacuum plays a major role in ECR beam generation and transportation. Large number vacuum pumps, gate valves, vacuum gauges have been used in the entire system which i...

A compact, high brightness 13.56 MHz inductively coupled plasma ion source without any axial or radial multicusp magnetic fields is designed for the production of a focused ion beam. Argon ion current of density more than 30 mA/cm(2) at 4 kV potential is extracted from this ion source and is characterized by measuring the ion energy spread and brig...

The ion energy distribution of inductively coupled plasma ion source for focused ion beam application is measured using a four grid retarding field energy analyzer. Without using any Faraday shield, ion energy spread is found to be 50 eV or more. Moreover, the ion energy distribution is found to have double peaks showing that the power coupling to...

This paper describes the design of an ultra wide band waveguide to coaxial adapter in S-band and Ku-band frequency spectrum. The uniqueness in this design is the introduction of a hemispherical cap probe with cylindrical tuning posts. The effect of hemispherical cap adapter incorporated in this design on the reflection, transmission and bandwidth i...

A high brightness inductively coupled plasma ion source based focused ion beam system is being developed. This system is intended to produce a low energy high current micron size beam of the heavier gaseous elements for high speed, micro milling applications. The basic aim of this development is to cater the needs of those applications which cannot...

An inductively coupled plasma ion source based micro machining system is being developed. The system parameters, in which mainly the source parameters like brightness, ion energy spread and source size, are optimized for increasing the efficiency of the system. Preliminary tests show 6 KeV Argon ion beam focused to 1.4 micron size with current dens...

Phase transition from anatase to rutile for the 70nm TiO2 crystallite has been investigated by annealing at different temperatures followed by TDPAC measurement of these TiO2 crystallites adsorbed with 181Hf tracer. The width of the peaks in XRD spectra for TiO2 crystallites annealed at different temperatures indicates the growth of the crystallite...

Summary form only given. Ions with low energy spread find immense applications in many fields such as FIB, SIMS, ion beam lithography etc. The work has been started to design an efficient and compact plasma based ion source for the application of FIB. It is aimed to generate very low energy spread ions of various gaseous and metallic species. A 13....

Electron Cyclotron Resonance Ion Sources (ECRIS) are known to produce intense X-rays of the order of 100's of keV. Energy of electrons in the resonantly heated microwave plasma has been estimated by analyzing the Bremsstrahlung spectra obtained using a standard alkali halide (NaI [Ti]) crystal detector. Experiments were carried out on argon plasma...

Liquid Metal Ion Source (LMIS) and Gas Field Emission Ion Source (GFEIS) are the major ones in micromachining applications so far. They have limitations of contaminations and low throughput. Plasma based ion sources can produce heavier ions for higher throughput, lighter ions for fabrication of higher resolution structures, ions for doping, ion ass...

A 2.45 GHz microwave ion source to produce 30mA cw proton beam at 100keV and a low energy beam transport system to characterize the beam properties are being developed at VECC. This beam will be first bunched using a sinusoidal buncher and then it will be injected into the central region of a 10 MeV compact cyclotron. The main aim of this project i...

Total electron yields and the most probable electron energy have been measured for impact of Oq+ (q=1–7) ions at near-normal incidence on a clean Al(110) single-crystal target. The projectile velocities were varied in the range from 0.08 a.u. to 0.6 a.u. The contributions from potential emission (PE) and kinetic emission (KE) to the total yields ha...

ECR ion source provides dc beam. When dc beam is injected into the cyclotron, only a part of it is accepted in the desired phase range for the proper acceleration. In order to enhance the beam current from VEC, which uses an external injection system, a single harmonic buncher for bunching heavy ion beam from the ECR ion source has been designed in...

The indigenously developed electron cyclotron resonance heavy ion source of Variable Energy Cyclotron Centre (VECC) has been upgraded to operate at high magnetic field mode for improved high charge state heavy ion performance. The enhancement in the performance of the upgraded source as well as its long term stability have been described.

The indigenously developed electron cyclotron resonance heavy ion source of Variable Energy Cyclotron Centre (VECC) has been upgraded to operate at high magnetic field mode for improved high charge state heavy ion performance. The enhancement in the performance of the upgraded source as well as its long term stability have been described.