Shankar Lal - Academia.edu (original) (raw)
Papers by Shankar Lal
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Abstract An Infrared Free Electron Laser (IR-FEL) has been designed and developed at RRCAT for po... more Abstract An Infrared Free Electron Laser (IR-FEL) has been designed and developed at RRCAT for potential use in the IR/THz spectroscopy of materials in low temperature and high magnetic field environment. The first commissioning experiments on the IR-FEL setup were performed in 2016, but the out-coupled power achieved in these experiments was two to three orders of magnitude lower than the saturated out-coupled power predicted by the FEL design simulations, mainly due to certain limitations in its injector system. The setup has recently undergone a major upgrade with the installation and commissioning of a new injector system, and lasing at a wavelength of 28 μ m has recently been observed in the setup. This is the first saturation of lasing of an FEL in India, with a measured Continuous Wave (CW) out-coupled IR power of 5 - 7.3 mW. This paper discusses the present status of the IR-FEL project at RRCAT, and the results from recent commissioning experiments leading to lasing in the setup.
Physical Review Accelerators and Beams
After the successful commissioning of the European XFEL in pulsed mode, continuous wave (CW) mode... more After the successful commissioning of the European XFEL in pulsed mode, continuous wave (CW) mode operation of European X-ray Free-Electron Laser (XFEL) is under considerations for future upgrade. DESY is push-ing R on CW electron sources. A fully superconducting CW gun is under experimental development at DESY in Hamburg, and a normal conducting (NC) CW gun is under physics design at the Photo Injector Test facility at DESY in Zeuthen (PITZ) as a backup option. A 217 MHz NC CW gun is developed from the LBNL 187 MHz VHF gun, with enhancement on both cathode gradient and gun voltage to further improve beam brightness. This paper presents the cavity RF design, multipacting (MP) simula-tions and beam dynamics studies.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2018
An algorithm is proposed for the design of a mode standing wave buncher structure with variable c... more An algorithm is proposed for the design of a mode standing wave buncher structure with variable cell lengths. It employs a two-parameter, multi-step approach for the design of the structure with desired resonant frequency and field flatness. The algorithm, along with analytical scaling laws for the design of the RF power coupling slot, makes it possible to accurately design the structure employing a freely available electromagnetic code like SUPERFISH. To compensate for machining errors, a tuning method has been devised to achieve desired RF parameters for the structure, which has been qualified by the successful tuning of a 7-cell buncher to mode frequency of 2856 MHz with field flatness <3% and RF coupling coefficient close to unity. The proposed design algorithm and tuning method have demonstrated the feasibility of developing an S-band accelerating structure for desired RF parameters with a relatively relaxed machining tolerance of ∼25 μm. This paper discusses the algorithm for the design and tuning of an RF accelerating structure with variable cell lengths.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2021
A three-cell 1.3 GHz, Normal Conducting (NC) buncher is designed for a possible future upgrade of... more A three-cell 1.3 GHz, Normal Conducting (NC) buncher is designed for a possible future upgrade of the European XFEL to operate in a continuous-wave (CW) / long pulse (LP) mode. The RF geometry of the buncher is optimized for high shunt impedance, large mode separation as well as multipacting free in the operation range. The bunchersupport cavity voltage of 400 kV with an RF power dissipation of 14 kW. A tapered waveguide-based RF power coupler is designed to feed the RF power to the buncher. The RF power coupler port is optimized for field asymmetry compensation. The thermal load due to RF power dissipation is analyzed using Multiphysics simulations in CST and a simplified cooling scheme is designed.
2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2019
Physical Review Accelerators and Beams, 2020
Journal of The Electrochemical Society, 2021
Current paper reports the fabrication of an exceptional and cost-effective electrochemical nanose... more Current paper reports the fabrication of an exceptional and cost-effective electrochemical nanosensor for the ultra-sensitive determination of Hydroquinone (HQ) using MoO3 nanostructures. The characterization through versatile analytical techniques such as Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray diffractogram (XRD), Atomic Force Microscopy (AFM) and Zeta sizer-potential (ZS-P) reveals that engineered Molybdenum oxide (MoO3) nanostructures are highly crystalline in nature, phase purity homogeneity and size around 20 nm, respectively. The MoO3 nanostructures were applied as electro nanosensor for the effective determination of HQ using Cyclic voltammetry. For efficient analysis of HQ, the bare glassy carbon electrode was modified with synthesized MoO3 NS as sensitive sensing nanoprobe. HQ was sensitively determined at scan rate of 70 mV s−1, borate supporting electrolyte with pH 8, and potential (V) range (−0.4 to 0.4 V vs Ag/AgCl). Th...
Physical Review Accelerators and Beams, 2020
2016 19th Conference of Open Innovations Association (FRUCT), 2016
Every cloud data center has a geographical location, which is known to, at least, its owner. Stil... more Every cloud data center has a geographical location, which is known to, at least, its owner. Still, it is a challenge for a cloud customer to discover indisputably the location of the data center, which hosts an active cloud based service and its data. Knowing the location is necessary to assess that pertinent geographical obligations of service level agreements and legal requirements are fulfilled. For example, several countries have legislation that denies processing private data of its citizens in countries that do not have compliant legislation. This paper presents existing technologies that can be used to resolve and assess the geographical location of a cloud servers.
Journal of Physics: Conference Series, 2019
A free-electron laser based THz source is undergoing design studies at the Photo Injector Test fa... more A free-electron laser based THz source is undergoing design studies at the Photo Injector Test facility at DESY in Zeuthen (PITZ). It is considered as a prototype for pump-probe experiments at the European XFEL, benefiting from the fact that the electron beam from the PITZ facility has an identical pulse train structure as the XFEL pulses. In the proposed proof-of-principle experiment, the electron beam (up to 4 nC bunch charge and 200 A peak current) will be accelerated to 16-22 MeV/c to generate SASE radiations in an LCLS-I undulator in the THz range between 60 and 100 pm with an expected energy of up to ~1 mJ/pulse. In this paper, we report our simulations on the optimization of the photo-injector and the design of the transport and matching beamline. Experimental investigations on the generation, characterization and matching of the high charge beam in the existing 22-m-long beamline will also be presented.
Journal of Physics: Conference Series, 2019
Laser pulse shaping is one of the key elements to generate low emittance electron beams with RF p... more Laser pulse shaping is one of the key elements to generate low emittance electron beams with RF photoinjectors. Ultimately high performance can be achieved with ellipsoidal laser pulses, but 3-dimensional shaping is challenging. High beam quality can also be reached by simple transverse pulse shaping, which has demonstrated improved beam emittance compared to a transversely uniform laser in the ‘pancake’ photoemission regime. In this contribution we present the truncation of a Gaussian laser at a radius of approximately one sigma in the intermediate (electron bunch length directly after emission about the same as radius) photoemission regime with high acceleration gradients (up to 60 MV/m). This type of electron bunch is used e.g. at the European XFEL and FLASH free electron lasers at DESY, Hamburg site and is being investigated in detail at the Photoinjector Test facility at DESY in Zeuthen (PITZ). Here we present ray-tracing simulations and experimental data of a laser beamline up...
Review of Scientific Instruments, 2016
Coupling of RF power is an important aspect in the design and development of RF accelerating stru... more Coupling of RF power is an important aspect in the design and development of RF accelerating structures. RF power coupling employing coupler loops has the advantage of tunability of β, the transmission line to cavity coupling coefficient. Analytical expressions available in literature for determination of size of the coupler loop using Faraday’s law of induction show reasonably good agreement with experimentally measured values of β below critical coupling (β ≤ 1) but show large deviation with experimentally measured values and predictions by simulations for higher values of β. In actual accelerator application, many RF cavities need to be over-coupled with β > 1 for reasons of beam loading compensation, reduction of cavity filling time, etc. This paper discusses a modified analytical formulation by including the effect of loop inductance in the determination of loop size for any desired coupling coefficient. The analytical formulation shows good agreement with 3D simulations and...
The Review of scientific instruments, 2014
The RF properties of an accelerating structure, and the pulse structure and charge per bunch in t... more The RF properties of an accelerating structure, and the pulse structure and charge per bunch in the electron beam propagating through it are important parameters that determine the impact of beam loading in the structure. The injector linac of the Compact Ultrafast Terahertz Free-Electron Laser (CUTE-FEL) has been operated with two different pulse structures during initial commissioning experiments and the effect of beam loading on the accelerated electron beam parameters has been studied analytically for these two pulse structures. This paper discusses the analytical study of beam loading in a Standing Wave, Plane Wave Transformer linac employed in the CUTE-FEL setup, and a possible technique for its compensation for the electron beam parameters of the CUTE-FEL. A parametric study has been performed to study beam loading for different beam currents and to optimize injection time of the electron beam to compensate beam loading. Results from the parametric study have also been used t...
2013 IEEE International Conference on Computational Intelligence and Computing Research, 2013
ABSTRACT
Review of Scientific Instruments, 2011
Developing a photocathode RF gun with the desired RF properties of the π-mode, such as field bala... more Developing a photocathode RF gun with the desired RF properties of the π-mode, such as field balance (eb) ∼1, resonant frequency fπ = 2856 MHz, and waveguide-to-cavity coupling coefficient βπ ∼1, requires precise tuning of the resonant frequencies of the independent full- and half-cells (ff and fh), and of the waveguide-to-full-cell coupling coefficient (βf). While contemporary electromagnetic codes and precision machining capability have made it possible to design and tune independent cells of a photocathode RF gun for desired RF properties, thereby eliminating the need for tuning, access to such computational resources and quality of machining is not very widespread. Therefore, many such structures require tuning after machining by employing conventional tuning techniques that are iterative in nature. Any procedure that improves understanding of the tuning process and consequently reduces the number of iterations and the associated risks in tuning a photocathode gun would, therefo...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008
An important aspect of the development of multi-cell RF accelerating structures is tuning the res... more An important aspect of the development of multi-cell RF accelerating structures is tuning the resonant frequency f of the operating mode, field balance e b , and waveguide to cavity coupling coefficient β to the desired values. Earlier theoretical analyses have not been able to predict all three ...
Journal of Physics: Conference Series, 2012
In this paper, we report on the development of a brazing process for an ultra-high vacuum (UHV) c... more In this paper, we report on the development of a brazing process for an ultra-high vacuum (UHV) compatible photocathode RF gun structure developed at our Centre. The choice of brazing alloy and its form, brazing clearance between parts to be joined and the brazing cycle adopted have been qualified through metallographic examination of identical joints on an OFE copper prototype that was cut open after brazing. The quality of brazed joint not only affects the UHV compatibility of the gun, but also influences the RF parameters finally achieved. A 2-D electromagnetic code, SUPERFISH, was used to predict the variation in RF parameters before and after brazing considering actual brazing clearances provided between the parts to be joined. Results obtained from low power RF measurements on the brazed gun structure confirm the integrity of the brazed joints and show good agreement with those predicted by electromagnetic simulations. The brazed gun structure has been leak-tested and pumped down to a vacuum level limited by the vacuum compatibility of the flange-fittings employed in the setup.
Journal of Physics: Conference Series, 2012
ABSTRACT Commonly used materials for accelerator components are those which are vacuum compatible... more ABSTRACT Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Abstract An Infrared Free Electron Laser (IR-FEL) has been designed and developed at RRCAT for po... more Abstract An Infrared Free Electron Laser (IR-FEL) has been designed and developed at RRCAT for potential use in the IR/THz spectroscopy of materials in low temperature and high magnetic field environment. The first commissioning experiments on the IR-FEL setup were performed in 2016, but the out-coupled power achieved in these experiments was two to three orders of magnitude lower than the saturated out-coupled power predicted by the FEL design simulations, mainly due to certain limitations in its injector system. The setup has recently undergone a major upgrade with the installation and commissioning of a new injector system, and lasing at a wavelength of 28 μ m has recently been observed in the setup. This is the first saturation of lasing of an FEL in India, with a measured Continuous Wave (CW) out-coupled IR power of 5 - 7.3 mW. This paper discusses the present status of the IR-FEL project at RRCAT, and the results from recent commissioning experiments leading to lasing in the setup.
Physical Review Accelerators and Beams
After the successful commissioning of the European XFEL in pulsed mode, continuous wave (CW) mode... more After the successful commissioning of the European XFEL in pulsed mode, continuous wave (CW) mode operation of European X-ray Free-Electron Laser (XFEL) is under considerations for future upgrade. DESY is push-ing R on CW electron sources. A fully superconducting CW gun is under experimental development at DESY in Hamburg, and a normal conducting (NC) CW gun is under physics design at the Photo Injector Test facility at DESY in Zeuthen (PITZ) as a backup option. A 217 MHz NC CW gun is developed from the LBNL 187 MHz VHF gun, with enhancement on both cathode gradient and gun voltage to further improve beam brightness. This paper presents the cavity RF design, multipacting (MP) simula-tions and beam dynamics studies.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2018
An algorithm is proposed for the design of a mode standing wave buncher structure with variable c... more An algorithm is proposed for the design of a mode standing wave buncher structure with variable cell lengths. It employs a two-parameter, multi-step approach for the design of the structure with desired resonant frequency and field flatness. The algorithm, along with analytical scaling laws for the design of the RF power coupling slot, makes it possible to accurately design the structure employing a freely available electromagnetic code like SUPERFISH. To compensate for machining errors, a tuning method has been devised to achieve desired RF parameters for the structure, which has been qualified by the successful tuning of a 7-cell buncher to mode frequency of 2856 MHz with field flatness <3% and RF coupling coefficient close to unity. The proposed design algorithm and tuning method have demonstrated the feasibility of developing an S-band accelerating structure for desired RF parameters with a relatively relaxed machining tolerance of ∼25 μm. This paper discusses the algorithm for the design and tuning of an RF accelerating structure with variable cell lengths.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2021
A three-cell 1.3 GHz, Normal Conducting (NC) buncher is designed for a possible future upgrade of... more A three-cell 1.3 GHz, Normal Conducting (NC) buncher is designed for a possible future upgrade of the European XFEL to operate in a continuous-wave (CW) / long pulse (LP) mode. The RF geometry of the buncher is optimized for high shunt impedance, large mode separation as well as multipacting free in the operation range. The bunchersupport cavity voltage of 400 kV with an RF power dissipation of 14 kW. A tapered waveguide-based RF power coupler is designed to feed the RF power to the buncher. The RF power coupler port is optimized for field asymmetry compensation. The thermal load due to RF power dissipation is analyzed using Multiphysics simulations in CST and a simplified cooling scheme is designed.
2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), 2019
Physical Review Accelerators and Beams, 2020
Journal of The Electrochemical Society, 2021
Current paper reports the fabrication of an exceptional and cost-effective electrochemical nanose... more Current paper reports the fabrication of an exceptional and cost-effective electrochemical nanosensor for the ultra-sensitive determination of Hydroquinone (HQ) using MoO3 nanostructures. The characterization through versatile analytical techniques such as Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray diffractogram (XRD), Atomic Force Microscopy (AFM) and Zeta sizer-potential (ZS-P) reveals that engineered Molybdenum oxide (MoO3) nanostructures are highly crystalline in nature, phase purity homogeneity and size around 20 nm, respectively. The MoO3 nanostructures were applied as electro nanosensor for the effective determination of HQ using Cyclic voltammetry. For efficient analysis of HQ, the bare glassy carbon electrode was modified with synthesized MoO3 NS as sensitive sensing nanoprobe. HQ was sensitively determined at scan rate of 70 mV s−1, borate supporting electrolyte with pH 8, and potential (V) range (−0.4 to 0.4 V vs Ag/AgCl). Th...
Physical Review Accelerators and Beams, 2020
2016 19th Conference of Open Innovations Association (FRUCT), 2016
Every cloud data center has a geographical location, which is known to, at least, its owner. Stil... more Every cloud data center has a geographical location, which is known to, at least, its owner. Still, it is a challenge for a cloud customer to discover indisputably the location of the data center, which hosts an active cloud based service and its data. Knowing the location is necessary to assess that pertinent geographical obligations of service level agreements and legal requirements are fulfilled. For example, several countries have legislation that denies processing private data of its citizens in countries that do not have compliant legislation. This paper presents existing technologies that can be used to resolve and assess the geographical location of a cloud servers.
Journal of Physics: Conference Series, 2019
A free-electron laser based THz source is undergoing design studies at the Photo Injector Test fa... more A free-electron laser based THz source is undergoing design studies at the Photo Injector Test facility at DESY in Zeuthen (PITZ). It is considered as a prototype for pump-probe experiments at the European XFEL, benefiting from the fact that the electron beam from the PITZ facility has an identical pulse train structure as the XFEL pulses. In the proposed proof-of-principle experiment, the electron beam (up to 4 nC bunch charge and 200 A peak current) will be accelerated to 16-22 MeV/c to generate SASE radiations in an LCLS-I undulator in the THz range between 60 and 100 pm with an expected energy of up to ~1 mJ/pulse. In this paper, we report our simulations on the optimization of the photo-injector and the design of the transport and matching beamline. Experimental investigations on the generation, characterization and matching of the high charge beam in the existing 22-m-long beamline will also be presented.
Journal of Physics: Conference Series, 2019
Laser pulse shaping is one of the key elements to generate low emittance electron beams with RF p... more Laser pulse shaping is one of the key elements to generate low emittance electron beams with RF photoinjectors. Ultimately high performance can be achieved with ellipsoidal laser pulses, but 3-dimensional shaping is challenging. High beam quality can also be reached by simple transverse pulse shaping, which has demonstrated improved beam emittance compared to a transversely uniform laser in the ‘pancake’ photoemission regime. In this contribution we present the truncation of a Gaussian laser at a radius of approximately one sigma in the intermediate (electron bunch length directly after emission about the same as radius) photoemission regime with high acceleration gradients (up to 60 MV/m). This type of electron bunch is used e.g. at the European XFEL and FLASH free electron lasers at DESY, Hamburg site and is being investigated in detail at the Photoinjector Test facility at DESY in Zeuthen (PITZ). Here we present ray-tracing simulations and experimental data of a laser beamline up...
Review of Scientific Instruments, 2016
Coupling of RF power is an important aspect in the design and development of RF accelerating stru... more Coupling of RF power is an important aspect in the design and development of RF accelerating structures. RF power coupling employing coupler loops has the advantage of tunability of β, the transmission line to cavity coupling coefficient. Analytical expressions available in literature for determination of size of the coupler loop using Faraday’s law of induction show reasonably good agreement with experimentally measured values of β below critical coupling (β ≤ 1) but show large deviation with experimentally measured values and predictions by simulations for higher values of β. In actual accelerator application, many RF cavities need to be over-coupled with β > 1 for reasons of beam loading compensation, reduction of cavity filling time, etc. This paper discusses a modified analytical formulation by including the effect of loop inductance in the determination of loop size for any desired coupling coefficient. The analytical formulation shows good agreement with 3D simulations and...
The Review of scientific instruments, 2014
The RF properties of an accelerating structure, and the pulse structure and charge per bunch in t... more The RF properties of an accelerating structure, and the pulse structure and charge per bunch in the electron beam propagating through it are important parameters that determine the impact of beam loading in the structure. The injector linac of the Compact Ultrafast Terahertz Free-Electron Laser (CUTE-FEL) has been operated with two different pulse structures during initial commissioning experiments and the effect of beam loading on the accelerated electron beam parameters has been studied analytically for these two pulse structures. This paper discusses the analytical study of beam loading in a Standing Wave, Plane Wave Transformer linac employed in the CUTE-FEL setup, and a possible technique for its compensation for the electron beam parameters of the CUTE-FEL. A parametric study has been performed to study beam loading for different beam currents and to optimize injection time of the electron beam to compensate beam loading. Results from the parametric study have also been used t...
2013 IEEE International Conference on Computational Intelligence and Computing Research, 2013
ABSTRACT
Review of Scientific Instruments, 2011
Developing a photocathode RF gun with the desired RF properties of the π-mode, such as field bala... more Developing a photocathode RF gun with the desired RF properties of the π-mode, such as field balance (eb) ∼1, resonant frequency fπ = 2856 MHz, and waveguide-to-cavity coupling coefficient βπ ∼1, requires precise tuning of the resonant frequencies of the independent full- and half-cells (ff and fh), and of the waveguide-to-full-cell coupling coefficient (βf). While contemporary electromagnetic codes and precision machining capability have made it possible to design and tune independent cells of a photocathode RF gun for desired RF properties, thereby eliminating the need for tuning, access to such computational resources and quality of machining is not very widespread. Therefore, many such structures require tuning after machining by employing conventional tuning techniques that are iterative in nature. Any procedure that improves understanding of the tuning process and consequently reduces the number of iterations and the associated risks in tuning a photocathode gun would, therefo...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2008
An important aspect of the development of multi-cell RF accelerating structures is tuning the res... more An important aspect of the development of multi-cell RF accelerating structures is tuning the resonant frequency f of the operating mode, field balance e b , and waveguide to cavity coupling coefficient β to the desired values. Earlier theoretical analyses have not been able to predict all three ...
Journal of Physics: Conference Series, 2012
In this paper, we report on the development of a brazing process for an ultra-high vacuum (UHV) c... more In this paper, we report on the development of a brazing process for an ultra-high vacuum (UHV) compatible photocathode RF gun structure developed at our Centre. The choice of brazing alloy and its form, brazing clearance between parts to be joined and the brazing cycle adopted have been qualified through metallographic examination of identical joints on an OFE copper prototype that was cut open after brazing. The quality of brazed joint not only affects the UHV compatibility of the gun, but also influences the RF parameters finally achieved. A 2-D electromagnetic code, SUPERFISH, was used to predict the variation in RF parameters before and after brazing considering actual brazing clearances provided between the parts to be joined. Results obtained from low power RF measurements on the brazed gun structure confirm the integrity of the brazed joints and show good agreement with those predicted by electromagnetic simulations. The brazed gun structure has been leak-tested and pumped down to a vacuum level limited by the vacuum compatibility of the flange-fittings employed in the setup.
Journal of Physics: Conference Series, 2012
ABSTRACT Commonly used materials for accelerator components are those which are vacuum compatible... more ABSTRACT Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.