[en] A 9 MeV RF Electron linac for cargo-scanning has been successfully commissioned at ECIL, Hyderabad. The pulsed coupled-cavity on-axis linac operates at a frequency of 2856 MHz with pulse width of 6 μs and 200 Hz repetition rate. This linac has been RF-conditioned up to a peak power of 2.6 MW. Peak beam current of ∼100 mA has been measured at the output of the linac. X-ray dose of ∼ 24 Gy/min/m has been measured on the tantalum target. Beam size of ∼ 2 mm has been obtained on the target. This paper highlights the features of the 9 MeV linac, its performance with RF power, behaviour of the linac under beam loading and measurements done to determine the X-ray dose rates. (author)

[en] A 50 keV, 60mA microwave ion source is designed and being developed for many high current applications e.g. ADSS, neutron generator etc. The design parameters for plasma chamber, solenoid magnet and extractor geometry are described. PBGUNS code, used to design the five electrodes extraction geometry, gives the rms normalized emittance of the beam at the exit plane as 1.98e-2π mm-mrad. (author)

No abstract available

[en] A high intensity ECR proton/deuteron source is under development for Accelerator Driven Systems (ADS) and Neutron Generators. The high intensity low emittance and continuous wave (cw) proton/deuteron source is an essential requirement for such applications. The advantage of ECR ion source with no filament and no RF antenna is high reliability and long time operation

[en] Abiotic stresses represent the most limiting factors affecting agricultural productivity. In India more than 60% of total cultivated land is still rainfed and crops experience frequent droughts. Thus, we need to develop transgenic crops tolerant to drought, and other related abiotic stress factors such as salinity, low and high temperature stresses. At the National Research Centre on Plant Biotechnology, Indian Agricultural Research Institute (ICAR), we have initiated a programme on developing transgenic crops tolerant to a range of abiotic stresses. The major emphasis is on developing transgenic potato, tomato, mustard, rice and wheat. While, transgenic plants of potato. tomato and mustard have already been generated with osmotin gene and are at different stages of testing, other key genes imparting tolerance to abiotic stresses are being isolated from different species for producing transgenic rice and wheat cultivars tolerant to multiple stresses. Genes that have been isolated in our laboratory include ascorbate peroxidase gene (TaApx) and genes encoding transcription factor, CBFs (TaCBF2 and TaCBP3) from a drought tolerant wheat cultivar (C306), Lea1 cDNA from Brassica species, codA from Arthrobacter globiformis, and otsBA operon from E. coli. Apart from these stress-related genes, we have isolated a few stress-inducible promoters for deploying them in gene stacking in developing transgenic crops with enhanced tolerance to multiple abiotic stresses. The results will be presented. (author)

[en] 6 MeV RF Electron linac-based X-ray source has been designed and developed at APPD, BARC for X-ray radiography applications. The linac operates in S-band (2856 MHz) with pulse width of 3.4 µs and rep.rate 40-100 Hz at peak electron current of 160 mA and RF peak power of 2.2 MW to generate 6 MeV electrons. X-ray conversion is achieved with the use of a water-cooled tantalum target. A 200 mm x 200 mm X-ray field area is generated at the end of a 450 mm long trapezoidal collimator. Qualification of the linac as an X-ray source for radiography was carried out at dose level of 1-2 Gy/min at various exposure rates. Wire-type (ASTM E 747) and hole type (ASTM E 1025) penetrameters have been used. Sensitivity of ∼1- 2% has been achieved. It is observed that linac can be used for industrial radiography of steel of thickness 100 – 200 mm with acceptable density requirement. Focal spot size of ∼1 mm has been estimated using MTF method. This paper discusses the performance of the 6 MeV linac for experiments needed for qualification and the results obtained. (author)

[en] Control system for RF source of 30 MeV, 3 kW RF Linac for neutron generation is being developed. The system consists of two 15 MeV linac structures, each powered independently with klystron rated for 7.5 MW(pk)/7.5 kW(avg). Two klystron modulators of 160kV, 110A, 7μs and 250Hz feed pulsed power into the klystron, which produces RF power at 2856 MHz. The klystrons will be driven by low power RF driver amplifiers programmed for matching phase, frequency and power into the linac. Both the driver amplifiers are controlled through RS-232 Protocol. The HV pulsing and RF drive for the klystron has been interlocked with water flow, arc detector, SF6 gas pressure etc. The control system is designed using Real time embedded controller, where pulses for synchronization are being generated in FPGA. Most of the power supplies like electromagnet, HVDC, etc. are on RS-232 protocol. These power supplies are controlled via suitable RS-232 to Ethernet converter. State machine topology is being used to design the logic. The database for logging data is developed in SQL. This paper describes the details of the software implementation and hardware used to realize the control of the RF power source. (author)

[en] A prototype on-axis coupled cavity RF electron linac for industrial applications is under development. The linac has been designed to deliver a 10 MeV pulsed beam with an average power of 10 kW. The RF frequency is 2856 MHz, while the duty cycle and pulse repetition rate are 0.4% and 400 Hz respectively

[en] Prediction of air pollutants in particular those related to PM₁₀ has developed a huge interest in recent years, mainly due to its impact on environment and humans. There are a large number of factors that influence air pollutant prediction. The researcher has to select the most relevant one by combining different input variables combinations in order to find the combination that provides the best prediction by artificial neural network (ANN). In this work, applications of principal component analysis (PCA) are presented to solve the problem of selection of variables in the prediction of daily PM₁₀. This method is tested by utilizing time series data of solar radiation, vertical wind speed, atmospheric pressure, PM_2.5, benzene, NO and PM₁₀ for Varanasi, India. The results obtained shows that PCA-ANN predicts daily PM₁₀ with mean absolute percentage error (MAPE) of 9.88% and it predicts better than multiple linear regression models.

[en] The Mumbai Harbour Bay (MHB), Mumbai, India houses a large number of ports, industrial units and urban settlements thus the groundwater may be highly contaminated. In the present study short lived Ra isotopes (²²³Ra and ²²⁴Ra) input sources (viz. water exchange from Arabian Sea, input from Rivers and wastewater discharge, Diffusion of Ra from bottom sediments and desorption from suspended particles) and pathways of removal (radioactive decay and export during the low tide) were estimated in MHB individually. A mass balance for ²²³Ra and ²²⁴Ra in the bay indicated an imbalance of 53.38% and 71.68% respectively. The imbalance was assigned to contribution from submarine groundwater discharge (SGD) and using the concentration in the shallow groundwater (at 2 m depth) of ²²³Ra and ²²⁴Ra the SGD were estimated. Based on ²²³Ra and ²²⁴Ra, the SGD was estimated and found to be 33.4 × 10⁹ L day⁻¹ and 64.9 × 10⁹ L day⁻¹ respectively.