[en] We have deduced the muon energy spectrum from primary cosmic ray nucleon spectrum in the energy range 4 to 105 GeV using latest PAMELLA, CREAM AND ATIC-2 BALLOON-BORNE experimental data. The derived muon spectra have been compared with experimental data of CosmoAleph and as well as theoretical calculation of Bugaev and Hebbeker and Timmermans considering the validity if hypothesis of Feynman regarding scale invariance in particle production. (author)

[en] Bangladesh has a nuclear power program of its own and has been trying to setup a nuclear power reactor. For this reason the Bangladesh Atomic Energy Commission (BAEC) is very much interested to get uranium from indigenous sources. Considering the basic need of nuclear minerals and favourable geological setup for nuclear mineral exploration in Bangladesh, BAEC has been operating nuclear mineral exploration program by its limited resource. As Bangladesh is geologically made of solely sedimentary rocks, it is only possibility to mineralize sedimentary types of uranium deposits under favourable reducing environment, which tends to be deposited as commercial uranium ore. Considering the favourable criteria for uranium formation Bangladesh has been divided into 4 zones as the (1) Eastern Mobile Belt (EMB), (2) Stable Platform (SP), (3) Dauki Fault Belt (DFB) and (4) Dinajpur Slope (DS). The occurrence of uranium in Harargaj anticline is the most suitable indication of uranium potentiality in the EMB. The SP is characterized by the occurrences of Gondwana basins in the subsurface. These basins are quite similar to those exist in uranium bearing Gondwana basins of India, South Africa, Brazil, Argentina, Niger, Australia and Madagascar. The DFB is situated close to the Mahadek uranium belt in the southern fringe of Shillong plateau. Recent investigations has shown that number of anomalous radioactive sites have been detected in Jaintiapur, Sreepur and Jadukata river valley of DFB. These results indicate that uranium bearing solution is still flowing in this zone. So, it can be assumed that the solution has been flowing for very long geologic time and ore might have been formed in and around the DFB. The Dinajpur Slope is characterized by Siwalik sediments, which is capable of hosting uranium as found in India and Pakistan. Besides, the gravels beds of alluvial fans have originated from Darjeeling and Sikkim belts, that are two reportedly uranium potential zones of uranium. As Bangladesh is drained by the Padma-Meghna-Jamuna systems, there are numerous sand bars in those river channels. These sand bars are the prospective locations for uranium bearing minerals. In Bangladesh a regional reconnaissance survey was carried out in more than 2000 sq. km areas of greater Chittagong and Chittagong Hill Tracts and Sylhet districts that has resulted in the identification of more than 150 surface radiometric anomalies. Most of the samples collected from anomalous beds contain uranium ranging from 10 - 300 ppm. The highest radiometric counts occurred in Phooltala Reserve Forest within the Harargaj anticline of Moulavi bazar district, which was about 6000 cps (60 times the background counts). Chemical analysis of this sample has indicated the presence of 1020 ppm total uranium and two uranium bearing minerals namely uranothorite and thorianite have been discovered in the rock samples. Besides, anomalous reading of 25 times higher than the background was observed in the crystalline basement rocks at Mitapukur in Rangpur district. Moreover, in recent studies conducted by the Geological Survey of Bangladesh (GSB), higher radiometric counts have been observed in sand bar deposits of the Brahmaputra River. (author)

[en] Electron accelerators in the energy range 200 to 800 keV are used for various industrial applications like plastic modifications, surface treatment and irradiation of medical products. A 500 keV, 20 mA, 10 kW DC industrial electron accelerator for various applications such as polymerization, paint curing, cross linking of polymers and Teflon degradation etc. has been designed and developed as a part of the Indigenous Industrial Electron Accelerator Development programme at BARC. The first indigenous Industrial Electron Accelerator operational in India at 3 kW beam power has been commissioned. Various sub-systems, beam and product development experiments are described

[en] Accelerator and Pulse Power Division has taken up 3 Me V, 30 kW Industrial Electron Beam Accelerator Project which is coming up at EBC Kharghar, Navi Mumbai. This paper will discuss about the design feature, selection of materials, fabrication, inspection and testing requirements of the Accelerator Tank which is made in three segments with total height of 7 m and 2 m diameter. (author)

[en] Full text: A 500 keV, 20 mA, 10 kW DC Cockcroft Walton industrial electron accelerator has been designed and developed by APPD/BARC and commissioned at BRIT Vashi. This accelerator is currently operational at 3 kW beam power level. The accelerator has been operated at 200 to 400 keV and 1 mA to 9 mA levels several times. This paper describes the operational experience gained during first extraction of the beam and subsequent raising the beam power to 3 kW level. Three successful 8 hour test runs of the accelerator at 3 kW beam power were demonstrated. Beam energy, current and power stability was within ±1.0% ±3.5% and 3.8% respectively during 8 hour runs. This accelerator is now being employed for experiments on cross linking of polyethylene sheets and surface treatment of woods by RTDS/BARC

[en] Electron beams with beam energy in the range of 0.2 to 10 MeV have found a large number of industrial applications. Keeping this in mind, the development of a 3 MeV, 30 kw DC industrial electron accelerator has been taken up. The accelerator comprises of several sub systems. Major sub systems and their current status are described

[en] Full text: A 3 MeV, 10 mA, 30 kW DC Dynamitron type industrial electron accelerator has been designed and is being developed by APPD/BARC. This accelerator will be commissioned at Electron Beam Center, Kharghar, Navi Mumbai. The accelerator comprises of several sub systems namely: Accelerator Tank at a pressure of 6 kg/cm² of SF₆ gas, HVDC power supply, 120 kHz high power oscillator, step up transformer, RF electrodes assembly, High voltage multiplier column with terminal dome, Electron gun with La B₆ cathode, Accelerating tubes, Scan horn assembly with X and Y scanning magnets, turbo molecular pump based UHV system,Titanium foil (50 μm thick) holder, radiation shielding, computer control system and conveyor system for product handling. The other auxiliary facilities include Low conductivity water plant, Gas Handling plant, Ozone exhaust duct fitted with blowers, instrumentation and safety interlocks. This paper describes the design philosophy, important features of the major sub systems and the current status of the accelerator

[en] Full text: A 3 MeV electron beam accelerator is coming up at the electron beam centre, Kharghar, Navi Mumbai. A vacuum of the order of 1x10^-7 mbar is desired in the beam line of the accelerator. The UHV system is spread over a height of 6 meters. The total surface area exposed to vacuum is 65,000 cm² and the volume is 200 litres. Distributed pumping is planned, to avoid undesirable vacuum gradient between any two sections of the beam-line. The electron beam is scanned in an area of 6 cms x 100 cms and it comes out of the scan-horn through a titanium foil of 50 micron thick. Hence the vacuum system is designed in such a way that, in the event of foil rupture during beam extraction, the electron gun, accelerating column and the pumps can be protected from sudden air rush. The vacuum in the beam-line can also be maintained in this condition. After changing the foil, scan-horn area can be separately pumped to bring the vacuum level as desired and can be opened to the beam-line. The design, vacuum pumping scheme and the safety aspects are discussed in this paper

[en] A 3 MeV, 30 kW D.C. electron accelerator is being developed for installation at the Electron Beam Center at Khargar, Navi Mumbai to cater to industrial uses like cable irradiation. This paper describes the design of the scan horn and beam extraction window of this accelerator. (author)

[en] Full text: The 500 keV industrial electron beam accelerator at BRIT, Vashi, Navi-Mumbai is presently operational and is being employed for experiments on cross-linking of polyethylene sheets, paint curing, surface treatment of wood with polymer coating, irradiation of plastic granules for color changes and effect of x-rays produced on semi-conductor rectifiers. The design aspects of the high vacuum pumping system of the accelerator, construction of the foil-holder, the initial hurdles faced while assembling and integrating the foil-holder with the scan-horn, the effect of external high pressure on the high vacuum and achievement of ultimate vacuum are discussed in this paper