Sukhpal Singh

Gamma radiation shielding analysis of lead-flyash concretes

Six samples of lead-flyash concrete were prepared with lead as an admixture and by varying flyash content - 0%, 20%, 30%, 40%, 50% and 60% (by weight) by replacing cement and keeping constant w/c ratio. Different gamma radiation interaction parameters used for radiation shielding design were computed theoretically and measured experimentally at 662keV, 1173keV and 1332keV gamma radiation energy using narrow transmission geometry. The obtained results were compared with ordinary-flyash concretes. The radiation exposure rate of gamma radiation sources used was determined with and without lead-flyash concretes.

Studies on Effective Atomic Numbers and Electron Densities in Some Commonly Used Solvents

Abstract The effective atomic numbers and the electron densities of some commonly used solvents, i.e., ethanol, methanol, propanol, butanol, water, toluene, benzene, carbontetrachloride, acetonitrile, chlorobenzene, diethylether, and dioxane at the energies 279, 356, 662, 1173, and 1332 keV were calculated by using the measured mass attenuation coefficients in a well-collimated narrow beam transmission geometry. These values are found to be in good agreement with the theoretical values calculated based on XCOM data.

Gamma radiation shielding and health physics characteristics of diaspore-flyash concretes

Different gamma radiation interaction parameters has been measured experimentally for the prepared diaspore-flyash concretes at 59.54, 662, 1173 and 1332 keV using narrow-beam transmission geometry and results are found to be in good agreement with theoretical values computed with a computer programme, WinXCom. The radiation exposure rate and absorbed dose rate for the gamma radiation with and without shielding of diaspore-flyash concretes have been determined using linear attenuation results. The results show that on average, there is reduction of 95%, 53% and 40% in dose rate for gamma sources (241)Am, (137)Cs and (60)Co, respectively with diaspore-flyash concretes as shielding material. Other health physics parameters namely equivalent dose, effective dose, gamma flux and energy fluence rate have also been determined.

Measurement of indoor radon, thoron and their progeny levels in dwellings of Union Territory Chandigarh, India: correlation with radon exhalation rates

Presence of radon, thoron and their decay products in household environment is considered a potential health hazard. Measurement of their levels is an important aspect to assess the threat they may pose to humans. Considering this their measurement from some dwellings of Union Territory Chandigarh, India has been carried out. Seasonal variation of these values has also been studied. A correlation study of exhalation rates from soil samples of areas close to the dwellings has also been carried out. The indoor radon concentration varied from 7.9 ± 0.5 to 39.2 ± 2.3 Bq m−3 with an average of 23.3 Bq m−3 while the thoron concentration in the same dwellings varied from 0.15 ± 0.01 to 24.6 ± 1.0 Bq m−3 with an average of 10.7 Bq m−3. Annual effective dose varied from 0.3 to 1.4 mSv with an average of 0.8 mSv. The radon mass and surface exhalation rates from the soil samples varied from 0.9 to 1.9 mBq/kg/h with an average of 1.39 ± 0.29 mBq/kg/h and 20.7–42.3 mBq/m2/h with an average of 31.4 ± 6.8 mBq/m2/h, respectively. The value of in situ gamma dose found to be varied from 0.14 to 0.31 µSv/h.

Effect of Flyash Addition on Mechanical and Gamma Radiation Shielding Properties of Concrete

Six concrete mixtures were prepared with 0%, 20%, 30%, 40%, 50%, and 60% of flyash replacing the cement content and having constant water to cement ratio. The testing specimens were casted and their mechanical parameters were tested experimentally in accordance with the Indian standards. Results of mechanical parameters show their improvement with age of the specimens and results of radiation parameters show no significant effect of flyash substitution on mass attenuation coefficient.

Long Reach Coherent Optical OFDM System using Multiple Mid Link Spectral Inversion Modules

CO-OFDM is a very attractive modulation and multiplexing technique that is used in wideband optical systems as well as optical wireless systems. In this paper; performance of utilizing multiple optical phase conjugate (OPC) modules in CO-OFDM system as a midlink spectrum inverter has been analyzed in order to improve the performance of system in long-haul fiber-optic channel. Firstly, performance of COOFDM system investigated at 30Gb/s, 50Gb/s and 100Gb/s which successfully transmitted over 1800Km, 1440Km and 1080 Km link length respectively without using any optical phase conjugation module. Further multiple OPC modules used in order to compensate effects of Kerr non linearities.8400Km of long distance transmission has achieved with acceptable BER limits by incorporating 6 OPC modules each after 1200Km at 30Gb/s. Results are analyzed in terms of OSNR, Q-factor for varied launched power and results revealed that system performs best at 12dB input power and effects of SPM decreased by using multiple OPC modules. Index Terms optical phase conjugation, OSNR, error vector magnitude, self phase modulation, BER

Two Media Method: An Alternative Methodology for the Measurement of Attenuation Coefficients of Irregularly Shaped Samples

Abstract The two media method used to determine the linear attenuation coefficients of irregularly shaped samples without the knowledge of the thickness of the sample has been verified. The linear attenuation coefficient values of regularly and irregularly shaped flyash material samples have been measured by the two media method using five different materials as media. The obtained values of the linear attenuation coefficient were compared with the results of the standard narrow beam gamma-ray transmission method. The results were in good agreement.