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The Indian test facility (INTF) is a R&D facility under development at the Institute for Plasma Research, Gandhinagar, as part of the neutral beam development from negative ion source program. The major advantage of the INTF, besides developing beams from large ion sources, is to characterize and benchmark the ITER diagnostic neutral beam (DNB) to the desired specifications over transport lengths of ~21 m, a unique feature of this test bed. Such a study will establish the expected power to be delivered by DNB into the ITER plasma, an important parameter to estimate the S/N ratio expected from the He ash measurements by charge exchange recombination spectroscopy. It may be noted that DNB is a procurement package for India as an in-kind contribution to ITER. Extensive physics and thermomechanical calculations have been performed to finalize the component design and layout. Adequate choice of materials, and manufacturing and jointing processes compatible to ITER safety standards have been made in order to make the components adhere to the safety and quality classification, thereby ensuring that the components survive the ITER lifetime while operating in harsh nuclear environments. The components are currently in various phases of manufacturing, and the first operations of the INTF are anticipated in Q4 of 2019.

To characterize ITER Diagnostic Neutral Beam (DNB) system with full specification and to support IPR's negative ion beam based neutral beam injector (NBI) system development program, a R&D facility, named INTF is under commissioning phase. Implementation of a successful DNB at ITER requires several challenges need to be overcome. These issues are related to the negative ion production, its neutralization and corresponding neutral beam transport over the path lengths of ~ 20.67 m to reach ITER plasma. DNB is a procurement package for INDIA, as an in-kind contribution to ITER. Since ITER is considered as a nuclear facility, minimum diagnostic systems, linked with safe operation of the machine are planned to be incorporated in it and so there is difficulty to characterize DNB after onsite commissioning. Therefore, the delivery of DNB to ITER will be benefited if DNB is operated and characterized prior to onsite commissioning. INTF has been envisaged to be operational with the large size ion source activities in the similar timeline, as with the SPIDER (RFX, Padova) facility. This paper describes some of the development updates of the facility.

Experiment of Prototype High Voltage Bushing (PHVB) is an important step to validate the design of HV bushing (HVB) of DNB for its electrostatic performance. The experiment is performed considering scaled down configuration DNB HVB with similar operating parameters and maintaining comparable electric stresses. Applied voltage is restricted up to 60 kV considering it's scaled down configuration. To automate the entire experimental process and acquiring important experimental data for post analysis, a dedicated Data Acquisition and Control System (DACS) is designed. CRIO (compact reconfigurable input output) is a rugged, small sized hardware platform which combines the power of real time processor and FPGA bus. NI CRIO is now widely used as a controller for small scale experiments. For ensuring smooth control operation of the experiment; NI CRIO was selected as the controller for DACS of PHVB. In this paper the technical details of DACS design, implementation and test results are discussed.

The effect of low energy (300 eV) argon plasma treatment on the morphology of polycarbonate was studied by means of contact angle measurement, X-ray photoelectron spectroscopy (XPS), Vickers' micro hardness indentation and atomic force microscopy (AFM). The surface free energy (SFE) changes from 38.5 mJ/m2 to 74.9 mJ/m2 on increasing the treatment time and the corresponding contact angle was changed from 63° to 17°, which shows the enhancement in surface adhesion. The XPS analysis shows the increase of the C-O and C=O functional groups upon treatment. The Vickers' micro hardness was studied in the load range 10-500 gf. The micro hardness of the film increases with the treatment time. Atomic force microscopy (AFM) reveals that average surface roughness increases from 7.0 nm to 27.2 nm as treatment time increases.

The surfaces of polycarbonate films were treated by nitrogen plasma, in order to understand the effect of low energy ions on the surface modification of polycarbonate. The modified samples were characterized by micro-hardness tester, optical micrograph/atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and FTIR spectroscopy. It was observed that the hardness of the film increases as fluence increases. This may be attributed to the cross-linking effect as corroborated with FTIR spectra. XPS analysis indicates that chemical bonding on the surface of the film, especially C=O, C-O and C-C/C-H functional groups, was found to change due to plasma treatment. AFM analysis reveals that average surface roughness increases from 5.9 nm to 42.7 nm as fluence increases.

Surface production of negative ion is a dominating process in a high current negative ion source. In presence of surface produced negative ions, the plasma sheath near a metallic plane is modified and has been analysed in this report. The multivalued nature of electric potential at the sheath edge in electronegative plasma, determined by Bohm criterion is pursued in presence of surface produced negative ions.

The role of surface produced negative ions in a negative ion source on the sheath structure, which takes place in the surroundings of a metallic plane immersed in a plasma, is analysed using a simple model. It is well known that the Bohm criterion which determines the electric potential at the sheath edge can be multi-valued in electronegative plasmas. It is observed in this study that a multi-valued sheath potential equally holds well in the case of a negative ion source where surface production mechanism of negative ions also exists. Due to the presence of surface produced negative ions, the positive ion current flux towards the metallic plane increases and the sheath potential with respect to the metallic plane increases.