Indian Journal of Pure and Applied Physics

      Total visitors: 1,428  since 15-05-06

 ISSN: 0019-5596

CODEN: IJOPAU 44 (4) 277- 348

VOLUME  44

NUMBER 4

APRIL 2006

 

CONTENTS









Nuclear Physics

 

Determination of full energy peak efficiency of HpGe detector from 59.5 to 1332.5 keV

281

Ali Gültekin*, Gökay Kaynak  &  Orhan Gürler

 

Assessment of radon-222 concentrations and exhalation rates of rocks and building materials

287

A M El- Arabi*, A Abbady, N K Ahmed, R Michel, A H El-Kamel & A G E Abbady

 

Atomic and Molecular Physics

 

Steady-state absorption and fluorescence study: Dipole moments of coumarins

292

K Chandrasekhar, L R  Naik, H M  Suresh Kumar & N N  Math*

 

Elemental analysis of potteries using energy dispersive X-ray fluorescence technique

300

Ajay Kumar, M L Garg*, Nirmal Singh & V Vijayan

 

Application of computerised glow curve deconvolution to determine the spectroscopy of traps in KCl

308

U Ranita, B Arunkumar Sharma & S Nabadwip Singh*

 

Optical study and synthesis of porous silicon nanostructures

312

Amit Tyagi*, R Singh, M K Bansal & R K Soni

 

Normal coordinate analysis of urea meta nitrobenzoic acid crystal

315

S Gunasekaran*, R K Natarajan, D Syamala & R Rathikha

 

Spectral distribution and enhancement studies of (ZnS+HgO) base  electroluminophor

320

Sudhir Kumar Srivastava & Laxmi Kant Singh*

 

Synthesis, XRD and 57Fe Mössbauer studies of the pseudo-binary Fe1-xMnxSb2 alloys

325

R K Sharma & Y K Sharma*

 

 

 

 

 

Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics and Fluid Dynamics

 

Achieving high signal-to-noise ratio in transient reflectivity measurements

330

A R Vijayaragavan, R Chari* & S M Oak

 

Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties

 

Microwave study of hydration of cement with different waters

334

S Barathan*, D Govindarajan, G Sivakumar & K Raghu

 

Dielectric studies of H-bonded complexes of benzamide and nicotinamide with alcohols

339

U Sankar*, A Kingson Solomon Jeevaraj & T Thenappan

 

__________

*The corresponding author has been indicated by (*) mark in case of papers with more than one author.

 


 

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 281-286

 
Determination of full energy peak efficiency of HpGe detector from 59.5 to 1332.5 keV

Ali Gültekin*, Gökay Kaynak & Orhan Gürler

Faculty of Art and Science, University of Uludağ, 16059 Bursa, Turkey

Received 11 May 2005; revised 3 November 2005; accepted 16 January 2006

To detect very low radio activities in the environmental samples, it is sometimes necessary to know the full energy peak efficiency of the detector. This work proposes a full energy peak efficiency simulation which represents adequately the high purity germanium coaxial detector responses in the energy range 59.5-1332.5 keV and at distances of 5, 10 and 25 cm.

Keywords: Efficiency; HpGe detector; Monte Carlo simulation

IPC Code: G01T

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 287-291

Assessment of radon-222 concentrations and exhalation rates of rocks and building materials

A M El-Arabi, A Abbady, N K Ahmed, R Michel*, A H El-Kamel** & A G E Abbady

Physics Department, Faculty of Science Qena, South Valley University, Egypt

*Institute of the Radiation Protection and Radioecology, Hanover University, Germany

**Physics Department, Faculty of Science, Assiut University, Egypt

Received 14 March 2005; revised 22 November 2005; accepted 31 January 2006

One hundred samples were collected from two regions (Bir El-Sid and Wady El-Gemal ) in the Nile Valley. It contain various types of igneous and metamorphic rock samples (acidic dykes, intermediate dykes, basic dykes, serpentinite, metagabbro, menalge). Another set of samples were collected from different regions of Germany. Samples were analyzed and the concentrations in Bq/kg dry weight of radium were determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector. A direct method is used to measure 222Rn emanated from the samples, which was analyzed in laboratory using the portable radon monitor Prassi. 222Rn activity concentrations (Bq/m3) were in the range from 36.1± 2 to 96.4 ± 6, 17.8 ± 3 to 73.6 ± 4 and 18.0 ± 2 to 188.1± 15 Bq/m3 for samples collected from Bir Elsid, Wadi El-Gemal and samples from Germany respectively. The corresponding values of exhalation rates were from 0.0012 to 0.004, 0.005 to 0.015 and 0.007 to 0.0069 Bq/gs for these areas respectively.

Keywords: Radon, Building materials, Exhalation rates

IPC Code: H01J65/08

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 292-299

Steady-state absorption and fluorescence study: Dipole moments of coumarins

 

K Chandrasekhar#, L R Naik, H M Suresh Kumar$ & N N Math*

#Department of Physics, Basaveswar Engineering College Bagalkot

Department of Physics, Karnatak University, Dharwad 580 003

$Department of Physics, ICFAI Institute of Science & Technology, Bangalore 560 083

Received 16 August 2005; accepted 6 February 2006

The absorption and fluorescence spectra of 7-dimethylamino cyclopenta [c] coumarin (C138) and 4-methyl-piperidino [g] coumarin (C339) dyes were measured in neutral, aprotic and protic solvents. Solvatochromic shifts of absorption and fluorescence as a function of different solvent polarity parameters (bulk as well as microscopic) were analyzed for these dyes and the ground state dipole moment (mg) and the first excited singlet state dipole moment (me) were estimated to be
mg = 2.2 and 3.42 D and me = 4.58 and 5.2 D, respectively, for C138 and C339. The dipole moment values of mg = 3.4 D and mg = 3.8 D were also obtained for C138 and C339 respectively from ab- initio calculations. The results are compared and discussed.

Keyword: Dipole moments, Fluorescence spectra, Absorption spectra, Coumarins

IPC Code: G01J3/28

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 300-307

Elemental analysis of potteries using energy dispersive X-ray fluorescence technique

Ajay Kumar1†, M L Garg2, Nirmal Singh1 & V Vijayan3

1Department of Physics, Panjab University, Chandigarh 160 014

2Department of Biophysics, Panjab University, Chandigarh 160 014

3Institute of Physics, Sachivalaya Marg, Bhubaneswar 751 005

Received 13 June 2005; 8 November 2005; accepted 2 January 2006

Archaeological pottery samples belonging to four different civilizations from Sanghol, India, were analyzed by Energy Dispersive X-ray Fluorescence (EDXRF) technique using the fundamental parameter approach. The samples for elemental analysis were excited by 17.8 keV X-ray photons of Mo secondary exciter in conjunction with X-ray tube. Ten elements, namely, K, Ca, Ti, Mn, Fe, Cu, Zn, Rb, Sr and Y have been quantified. The experimental procedure adopted for elemental analysis was established by comparing the certified reference materials, obtained from National Institute of Standards and Technology (NIST), Chandigarh. It is concluded that the concentrations of the observed elements in pottery samples do not vary significantly for four different periods. The result indicates that the pottery of different periods was made from the same type of soil of the Sanghol region and pottery making was probably well developed art/technology at Sanghol.

Keywords: X-rays, EDXRF, Archaeological pottery samples

IPC Code: F21K2/04

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 308-311

Application of computerised glow curve deconvolution to determine the spectroscopy of traps in KCl

U Ranita, B Arunkumar Sharma & S Nabadwip Singh

Department of Physics, Manipur University, Imphal 795 003

Received 21 October 2005; accepted  30 January 2006

Computerised Glow Curve Deconvolution (CGCD) of a semiconducting/insulating material in principle is expected to provide its trap-spectroscopy, provided the deconvolution passes the goodness-of-fit test. In this paper, the trap-spectroscopy of KCl by deconvoluting its glow curve has been provided. The reason for the abnormal values of trapping parameters reported in literature is critically discussed keeping this present finding in mind.

Keywords:     Computerised glow curve deconvolution, Thermoluminescence, Trapping parameters, Coefficient of           determination (R2)

IPC Code:     F21K2/04

  

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 312-314

 

Optical study and synthesis of porous silicon nanostructures

 

Amit Tyagi, R Singh, M K Bansal & R K Soni*

Department of Physics, Bharat Institute of Technology, Meerut 250 103

*Department of Physics, Indian Institute of Technology, New Delhi 110 016

Email: amittyagi_14@hotmail.com

Received 30 August 2005; revised 23 January 2006; accepted 6 February 2006

Porous silicon nanostructures have been generated using laser assisted etching (photochemical etching). The shape and size of the nanostructures obtained, depend on the wavelength used. The dependence of Raman shift and photoluminescence on the shape and size of nanostructures was studied.

Keywords: Porous silicon, Nanostructures, Etching, Photoluminescence

IPC Code: H01F41/30

 

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 315-319

 

Normal coordinate analysis of urea meta nitro benzoic acid crystal

S Gunasekaran*, R K Natarajan, D Syamala & R Rathikha

*Postgraduate and Research Department of Physics, Pachaiyappa’s College, Chennai 600 030

Postgraduate and Research Department of Physics, Presidency College, Chennai 600 005

Received 5 August 2005; accepted 25 January 2006

Urea meta nitrobenzoic acid is a crystal with the molecular formula C8H7O4N3. A normal coordinate analysis (NCA) has been carried out on this molecule with a systematic set of symmetry coordinates following Wilson’s F-G matrix method based on Cs point group symmetry. The frequency assignments in the FTIR and FTR spectra have been presented. A reasonable set of potential constants evaluated for this molecule has been compared with those of related molecules and are in the characteristic range. The potential energy distribution has been evaluated using the vibrational spectral data and molecular parameters. The potential energy distribution value obtained reflects the correctness of the assignment mode.

Keywords: FTIR, FTR spectra, Urea meta nitrobenzoic acid crystal, Normal coordinate analysis, Potential energy distribution

IPC Code:      G0IJ3/00

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp 320-324

Spectral distribution and enhancement studies of (ZnS+HgO) base electroluminophor

Sudhir Kumar Srivastava & Laxmi Kant Singh

Department of Physics and Electronics, Dr.Ram Manohar Lohia Avadh University, Faizabad 224 001

Received 7 October 2004; revised 18 October 2005; accepted 2 January 2006

The enhancement effect of dielectric dispersed double band emitting (ZnS+HgO):Cu,Mn(H) electroluminescent material has been investigated under the concurrent excitation of ac fields and 3650 Å UV-radiation. The emissions in yellow region were found to show relatively larger enhancement than that in case of green emission. The instantaneous behaviour of the individual peaks (green and yellow) was critically recorded and was observed that both the emissions isolately behave almost similarly and exhibit an exponential decay or rise before attaining the saturation value. The maximum enhancement is always found to be less than 4/3.

Keywords: Luminescence, Electroluminescence, Photoluminescence

IPC Code: C09K 11/00

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 325-329 

Synthesis, XRD and 57Fe Mössbauer studies of the pseudo-binary

Fe1-xMnxSb2 alloys

 

R K Sharma & Y K Sharma*

Department of Physics, University of Rajasthan, Jaipur 302 004

*E-mail: yksharma@uniraj.ernet.in

Received; 25 May 2005; revised 8 November 2005; accepted 13 February 2006

The synthesis of the polycrystalline Fe1-xMnxSb2 alloys for 0.0 x 0.2 has been investigated. X-ray powder diffraction (XRD) patterns of three specimens revealed the formation of single phase orthorhombic crystal structure. Lattice parameters and unit cell volume increase with the increase in Mn concentration. 57Fe Mössbauer spectra measured for all the three specimens at 300K were analyzed in terms of a single quadrupole split doublet revealing paramagnetic character at this temperature.

Keywords: Mössbauer spectroscopy, Fe1-xMnxSb2 alloys, Paramagnetism, X-ray diffraction

IPC Code: G01J3/12

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 330-333

Achieving high signal-to-noise ratio in transient reflectivity measurements

A R Vijayaragavan1, R Chari2 & S M Oak2

1Physics Department, Anna University, Chennai 600 025;  2Centre for Advanced Technology, Indore 452 013

E-mail: chari@cat.ernet.in

Received 25 May 2005; revised 19 October 2005; accepted 16 November 2005

Transient reflectivity measurements using ultrashort pulse pump-probe techniques can provide very useful information on fast carrier dynamics in semiconductors. Several non-trivial problems encountered in measuring reflectivity changes have been described. These changes can be very small (DR/R ~10-3 or less) and hence measuring these small changes is not straightforward. The possible solutions in overcoming such problems have been described. Some preliminary results on a GaAs thin film have also been presented.

Keywords: Transient reflectivity, GaAs thin films

IPC Code: H01L

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 334-338

Microwave study of hydration of cement with different waters

S  Barathan,  D  Govindarajan,  G  Sivakumar & K  Raghu

Department of Physics, Annamalai University,  Annamalai Nagar  608 002

E-mail: sbarathan_au@rediffmail.com

Received 9 May 2005; revised 12 August 2005; accepted 9 January 2006

The dielectric constant and electrical conductivity of laboratory prepared cement paste, using X-band microwave technique in the frequency range 8.5-11.5 GHz have been studied. The cement was mixed with different waters, in a water to cement ratio (w/c) of 0.3, 0.4 and 0.5. With the help of dielectric constant and electrical conductivity, the hydration reactions of the cement pastes have been studied.

Keywords:     Dielectric constant, Microwave X-band, Cement paste, Electrical conductivity, Cement hydration

IPC Code: G01R27/26

Indian Journal of Pure & Applied Physics

Vol. 44, April 2006, pp. 339-344

 

Dielectric studies of H-bonded complexes of benzamide
and nicotinamide with alcohols

U Sankar*, A Kingson Solomon Jeevaraj & T Thenappan

Department of Physics, Alagappa University, Karaikudi, Tamilnadu

*Department of Physics, AKGS Arts College, Srivaikuntam, Tamilnadu

Received 15 June 2005; accepted 6 October 2005

The hydrogen-bonded complexes formed by benzamide and nicotinamide with alcohols in 1, 4-dioxan were studied at 303 K. The following alcohols were used: 2-butoxy ethanol, 2-ethyl hexanol, hexan-1-ol and isopropanol. The dipole moments of the complexes were determined using Huyskens method. The excess dipole moments of the complexes were obtained from bond angle data. The results show the domination of polarization effects and the non-feasibility of higher order complexations.

Keywords: Dielectric study, Hydrogen bonded complexes, Benzamide, Nicotinamide, Polarization effect

IPC Code: G01R27/26