Electronics Laboratory

Research and Development Activities

• Power Supply, TEC based temperature controllers, control electronics and programmable user interface for Green laser photo coagulator
• Power supplies for Arc-lamp Pumped CW Solid State Laser Systems
• Power Supplies for flash-lamp-pumped Quasi-CW Solid State Lasers
• Power Supplies for Flash-lamp-pumped Pulsed Solid State lasers
• CO2 Laser Power supply for remote heating applications at VSSC, ISRO
• Ballast-less simmer power supply for flash-lamp-pumped solid-state lasers
• Laser diode power supply and control circuits for High Resolution Spectroscopy experiments

Group Members

Publications

• In Journals
• International Conferences
• National Symposiums

Power Supply, TEC based temperature controllers, control electronics and programmable user interface for Green laser photo coagulator

Green Laser Photo Coagulator System (GLPU-II) has been developed under MoU between Aurolab, Madurai and RRCAT with a view to develop an indigenous laser photo coagulator unit at low cost so that the diabetic retinopathy becomes affordable for poor diabetic patients. Laser diode power supply, temperature controllers and TEC drivers for diode and crystals, microcontroller based control and programmable user-interface with touch panel control have been developed. These sub-systems of electronics have been integrated with the laser system of the GLPU. The integrated system has been thoroughly tested and delivered to Aurolab, Madurai for clinical trials on human patients. The clinical trials have also been carried out successfully by doctors at Aravind Eye Care Hospital, Madurai.

Green Laser Photo Coagulator Unit – II (GLPU-II) with touch panel control	Laser diode Power Supply for GLPU-II

Power supplies for Arc-lamp Pumped CW Solid State Laser Systems:

(a) Power supply for CW Nd:YAG Laser for laser cladding applications at IGCAR

A power supply for 500W CW Nd:YAG laser system with programmable user interface and front panel has been developed, fabricated and commissioned at IGCAR for laser cladding applications. The power supply incorporates buck converter based dc current source, booster source, trigger source and control circuitry. It can deliver an adjustable output current in the range of 5 - 50A with a compliance voltage of 180V.

(b) Power supply for CW Nd:YAG Laser for laser Material Processing applications at BARC

A 20kW power supply for dual arc-lamp pumped 800W CW Nd:YAG laser system with programmable user interface has been developed, fabricated and commissioned at MSD, Material Group, BARC successfully along with the laser for Laser material processing applications including Laser Rapid Manufacturing.

Power Supplies for flash-lamp-pumped Quasi-CW Solid State Lasers:

(a) Power supply for Laser Welding System for Cardiac Pacemaker Shells

The power supply for flash-lamp-pumped Nd:YAG laser based welding system for Cardiac Pacemaker shells has been developed and was delivered along with the Nd:YAG laser system to a public limited company. The system is being used for manufacturing of cardiac pacemakers indigenously.

(b) Power Supply for Industrial Nd:YAG laser for Laser Material Processing Applications

A power supply for flash-lamp-pumped Nd:YAG laser based Material Processing system has been developed and delivered to Laser Lab, SSLD and is being used for various material processing applications from different R & D units of DAE and NPCIL. The pulse power source of the power supply system can deliver an average output power of 5kW and peak output power of 100kW. The output load current is adjustable from 100 to 300A, pulse width from 2 to 20 ms and pulse repetition rate up to 100PPS.

Power Supplies for Flash-lamp-pumped Pulsed Solid State lasers:

(a) Power supplies for Pulsed Nd:YAG Laser for thermal diffusivity experiments at IGCAR and BARC

A power supply for pulsed Nd:YAG laser system has been developed which incorporates a PFN charging source, simmer current source, trigger source and control circuitry. It can charge a PFN capacitance of 1500µF to an adjustable voltage in the range from 500V to 1200V at repetition rates up to 1 PPS. The stored energy in the PFN can be delivered to the flash lamp in 1ms to get a laser pulse of 18J. Two such power supply units along with the laser systems have been tested and commissioned at MCD, IGCAR and FCD, BARC for thermal diffusivity experiments.

(b) Power supply for Pulsed Nd:YAG Laser for laser cleaning and decontamination applications

A power supply for pulsed Nd:YAG laser incorporating a constant current PFN charging power supply based on LCL-T resonant converter operating at switching frequency of 100kHz has been developed. The PFN charging power supply can charge a capacitance of 40µF to an adjustable voltage in the range from 300V to 1200V at repetition rates up to 20PPS. The development of engineered version of the power supply is in progress to power the flash-lamp-pumped Nd:YAG laser for laser cleaning and decontamination applications.

CO2 Laser Power supply for remote heating applications at VSSC, ISRO

Power supply and control electronics for 100W CW CO2 laser has been developed and delivered to VSSC, ISRO, Trivendrum along with the laser system for remote heating applications.

Ballast-less simmer power supply for flash-lamp-pumped solid-state lasers

A ballast-less simmer current source of 1 A with a compliance voltage of 1400 V has been designed, developed and tested on actual flash lamp load along with the main pulse power source delivering pulsed power to the flash lamp. It can deliver stable simmer current adjustable from 0.3 A to 1 A without using any ballast, thus eliminating the energy loss in resistive ballast and improving efficiency of the system. The power supply uses resonant converter operating at switching frequency in the range of 35 to 70 kHz.

Laser diode power supply and control circuits for High Resolution Spectroscopy experiments

A power supply for 50mW diode laser and a thermo-electric-cooler based temperature controller to maintain the temperature of the laser diode mounting block in the range of 18 to 30 deg C within +/-0.1 deg. C has been developed. Modulation facility in the driver current by an adjustable ramp signal to improve the stability of the system is also provided. A PZT driver for a frequency range of 0.1 to 100Hz with an output voltage in the range of +/- 20 V has been developed which can drive PZT by triangular and saw tooth waveforms with an adjustable dc level shift in the range of +/- 20V The circuits have been developed and delivered to Laser Physics Division, RRCAT.

Group Members

1. Shri R. Arya
2. Smt.Jagriti Khanwalkar
3. Shri Ashutosh Sharma
4. Shri Dipen M. Vachhani
5. Shri T.R.Sajith Kumar
6. Shri Dhruvdeep Narwat
7. Shri Vijay Bhawsar
8. Shri Gurupreet Singh
9. Shri Manoj Kumar
10. Shri Praveen Gaure
11. Smt.P.Shryner
12. Shri S.K.Sah
13. Shri C.B.Panwar
14. Shri A.A.Raju
15. Shri K.K.Pant
16. Shri G.C.Mukhopadhyay
17. Shri Tukaram Mahajan
18. Shri Anil K. Shrivastava

Publications

In Journals

1. Vijay Bhawsar, R. Arya and S.M. Oak,
   “Automation control and interface for diode-pumped solid-state lasers with adjustable parameters”
   Journal of Instrument Society of India , Vol. 39, No.4, pp. 253-255, December 2009.
   
   
2. A. Sharma , C.B Panwar , R. Arya , A.K Nath,
   "Design of a high frequency SMPS Powering laser diode",
   Journal of Instrument Society of India , Vol. 38, No.1, pp. 63-70, March, 2008.
   
   
3. Smita Chaube, Purushottam Joshi, Manoj Kumar, Rajesh Arya, A.K. Nath and Sanjay Kher,
   “Design and development of ling-periodgrating sensors for temperature monitoring”,
   Sadhana, Vol.32, Part 5,  pp.513-519, October 2007.
   
   
4. R.Arya, Joy Thomas M., A.G.Bhujle and D.D.Bhawalkar,
   “Arbitrary wave-form-pulsed power source for flash-lamp-pumped solid-state lasers”,
   Review of Scientific Instruments, Vol.71, No.6, pp.2589-2597, 2000.
   
   
5. R.Arya, Joy Thomas M., A.G.Bhujle and D.D.Bhawalkar,
   “Effects of simmer current on flash lamp impedance and their combined influence on the output of a quasi-CW Nd:YAG laser”,
   IEEE Journal of Quantum Electronics, Vol.36 , No.7,  pp.872-878, 2000.
   
   
6. R. Arya, Joy Thomas M., A.G.Bhujle and D.D.Bhawalkar,
   “A novel trigger system for flash lamp pumped solid state laser power supply”,
   Journal of Instrument Society of India, Vol.29, No.3, pp.131-135, 1999.
   
   
7. Y.V.S.T. Sai, T.P.S. Nathan, C.P.Navathe, R.Arya, P.Shryner, G.Mundra, D.K.Kohli, P. Khare, A.S.Rajarao and D.D.Bhawalkar,
   "Development of a CW CO2 laser system (Model C-40) for surgical applications",
   Journal of Instrument Society of India, Vol.23, No. 1-2, pp.16-26, 1993.

International Conferences:

1. R.Arya, V. Bhawsar, Joy Thomas M. and S.M. Oak,
   “Development of a Digitally Controlled SMPS for Arc-lamp-pumped High-power CW Solid-state Laserfor Laser Material Processing Applications”, International Conference on Instrumentation ICI-2009, pp. 124-125, Pune, January 21-23, 2010.
   
   
2. J. Khanwalkar, P. Shryner, R. Arya  and S. M. Oak,
   “Development and Optimization of SMPS based TEC driver and Temperature Controller for Diode-pumped Solid-state laser”,
   International Conference on Instrumentation ICI-2009, p.215, Pune, January 21-23, 2010.
   
   
3. Sharma Ashutosh , Panwar C.B., Arya R., and Oak S.M,
   “Cycle by cycle closed loop control techniques for SMPS based laser diode driver”,
   International Conference on Instrumentation, ICI-2009, Pune, p.166, January 21-23, 2010.
   
   
4. Vijay Bhawsar, R Arya, D. Narwat  and S. M. Oak,
   “A Digital Signal Controller based scheme for Interface and Digital Control for Flash Lamp Pumped Quasi CW Nd:YAG Lasers”,
   International Conference on Instrumentation ICI-2009, p.85, Pune, January 21-23, 2010
   
   
5. M.K.Saxena, S.D.V.S.Raju, R.Arya. S.Kher, S.M.Oak,
   “FPGA based distributed temperature sensor using optical fiber”,
   International Conference on Instrumentation ICI-2009, Pune, p.196, January 21-23, 2010.
   
   
6. B.N. Upadhyaya, Rajesh Arya, S.M.Oak,
   “  Applications of Industrial Nd:YAG lasers in maintenance of pressureized heavy water reactors”,
   International Conference on Peaceful Uses of Atomic Energy -2009, Vigyan Bhavan, New Delhi, September 29 – October 1, 2009.
   
   
7. V.K.Raghuvansi, A.K.Singh and Rajesh Arya,
   “Design and development of a D.C. Sputtering system for titanium thin film deposition inside ceramic cavities of kicker magnets of Indus II”,
   Fifth International Workshop on Mechanical Engineering/ Design of Synchrotron Radiation Equipment and Instrumentation/ Fifteenth Pan-American Synchrotron Radiation Instrumentation Conference (MEDSI/SRI 2008), University of Saskatchewan, Saskatoon, Saskatchewan, Canada,  June 10-13, 2008.
   
   
8. R. Arya, Joy Thomas M., A. G. Bhujle and D. D. Bhawalkar,
   “A programmable arbitrary wave-form-pulsed power source for flash-lamp-pumped solid-state lasers”,
   IEE Symposium on Pulsed Power-2001, London (U.K.), May1-2, 2001.
   
   
9. R. Arya, S. Krishnan and A.G. Bhujle,
   "Development of power supply and associated instrumentation of Nd:Glass laser oscillator and amplifier system",
   International Conference on Instrumentation-1996, IISc, Bangalore, Aug. 08-10,1996.

National Symposiums:

1. A. Sharma, R. Arya, C.B. Panwar, S. M. Oak,
   “A non-contact dc current measurement technique for laser diode based systems”,
   Eighth DAE-BRNS National Laser Symposium (NLS-08), New Delhi, p.45, January 7-10, 2009.
   
   
2. J. Khanwalkar, P. Shryner, R. Arya, S.M. Oak,
   “An efficient TEC driver for applications in diode-pumped solid-state lasers”,
   Eighth DAE-BRNS National Laser Symposium (NLS-08), New Delhi, p.43, January 7-10, 2009.
   
   
3. D. Narwat, V. Bhawsar, R. Arya, S.M. Oak,
   “Microcontroller based shutter control and interlock system for high-power lasers”,
   National Symposium on Instrumentation (NSI-33), Visakhapatnam, pp. 132-133, December 8-10, 2008.
   
   
4. J. Khanwalkar, P. Shryner, R. Arya, S.M. Oak,
   “A thermoelectric cooler based temperature controller for diode-pumped solid-state laser systems”,
   National Symposium on Instrumentation (NSI-33), Visakhapatnam, p.145, December 8-10, 2008.
   
   
5. V. Bhawsar, R. Arya, S.M. Oak ,
   “Automatic control and interface for diode-pumped solid-state lasers with adjustable pulse parameters”, National Symposium on Instrumentation (NSI-33), Visakhapatnam, December 8-10, 2008.
   
   
6. Manoj K. Saxena, SDVSJ Raju, R. Arya, S. Kher, S.M. Oak
   “Dealing with noise in Raman antistokes and stokes signals for distributed fiber temperature sensor – an investigation of window based FIR Filters and their effects”,
   National Symposium on Instrumentation (NSI-33), Visakhapatnam, December 8-10, 2008.
   
   
7. Dipen M. Vachhani, R. Arya and S. M. Oak,
   “Constant current capacitor charging power supply based on high-frequency, zero-voltage switched LCL-T resonant converter”,
   DAE BRNS National Laser Symposium-2007 (NLS-7), MS University of Baroda, Vadodara, p.52, December 17-20, 2007.
   
   
8. A. Sharma, R. Arya, S. M. Oak,
   “Energy meter circuit for quasi-CW lasers”,
   DAE-BRNS National Laser Symposium-2007 (NLS-7), MS University of Baroda, Vadodara, p.113, December 17-20, 2007.
   
   
9. Ambar Choubey, D. K. Agrawal, S. C. Vishwakarma, B. N. Upadhyaya, Sabi Ali, R. K. Jain, S. K. Sah, R. Arya, Jojo Joseph, K. V. Kashivishwanathan, S. M. Oak, “Laser cutting of Fast Breeder Test Reactor fuel subassembly in hot cell”,
   DAE-BRNS National Laser Symposium-2007 (NLS-7), MS University of Baroda, Vadodara, p.59, December 17-20, 2007.
   
   
10. B.N. Upadhyaya, S. C. Vishwakarma, Sabir Ali, V. Bhawsar, S. K. Sah, R. Arya, D.K.Agarwal, R.K.Jain, A. Chaube, S.M.Oak,
    “Development of an Efficient 880 W CW Nd:YAG Laser”
    DAE-BRNS National Laser Symposium-2007 (NLS - 7), MS University of Baroda, Vadodara, p.52 , December 17-20, 2007.
    
    
11. Vishal Agnihotri, K. Ranganathan, P. Hedaoo, P. Misra, Manoj Kumar, R. Arya, and S.M. Oak,
    “Diode-end-pumped, A-O Q-switched Nd:YVO4 laser for marking applications”,
    DAE-BRNS National Laser Symposium-2007 (NLS-7), MS University of Baroda, Vadodara, p.94, December 17-20, 2007.
    
    
12. Vijay Bhawsar, R. Arya and S. M. Oak,
    “Digital control for a switch mode Power Supply using digital signal controller”,
    National Symposium on Instrumentation (NSI-32), KSRCT, Tiruchengode, pp. 248-250, 2007.
    
    
13. Manoj Kumar, S. K. Sah, R. Arya and S. M. Oak,
    “Power Supply for CO2 Laser System for Fabrication of Long Period Gratings”,
    National Symposium on Instrumentation (NSI-32), KSRCT, Tiruchengode, pp. 263-264, 2007.
    
    
14. Sajith Kumar T.R., R.Arya, Manoj Kumar and A.K.Nath,
    "Better handling of reverse-revcovery charge of switching diode in pulsed power supply for flash-lamp-pumped solid-state-laser”,
    DAE-BRNS National Laser Symposium-2006 (NLS - 6), RRCAT, Indore, pp.419-420, December 5-8, 2006
    
    
15. J. Khanwalkar, R.Arya, A.K.Nath,
    "LCC Resonant Converter based Power Supply for high power Diode Laser”,
    DAE-BRNS National Laser Symposium-2006 (NLS - 6), RRCAT, Indore, pp.53-54, December 5-8, 2006.
    
    
16. B.N. Upadhyay, S.C. Vishwakarma, R. Arya and A.K. Nath,
    “Applications of Nd:YAG lasers in Indian nuclear power programme”,
    RRCAT newsletter, Vol.19, No.2, pp.24-28,  November 2006.
    
    
17. Vijay Bhawsar and R. Arya, “Micro-controller based reference waveform generator for Nd:YAG laser”,
    National Symposium on Instrumentation (NSI-31),
    Institute of Technology and Management, Gwalior, pp. 184-185, October 12 –25, 2006.
    
    
18. A. Sharma, R. Arya and A.K.Nath,
    “Design of a high-frequency SMPS powering laser diode”,
    National Symposium on Instrumentation (NSI-31), Institute of Technology and Management, Gwalior, pp. 192-193, October 12 –25, 2006.
    
    
19. B. N. Upadhyaya, S. C. Vishwakarma, A. Choubey, P. Misra, R. K. Jain, Sabir Ali, D. K. Agrawal, R. Arya and T.P.S. Nathan,
    “Development of an Efficient 5kW Peak Power Nd:YAG Laser with Time-shared Fiber Optic Beam Delivery”,
    International Conference on Optics and Optoelectronics (ICOL-2005), IRDE, Dehradun, pp.211, December 12-15, 2005.
    
    
20. R. Arya, Joy Thomas M. and A.K. Nath,
    “A novel and efficient pulsed power source for flash-lamp-pumped solid-state-lasers”,
    DAE-BRNS National Laser Symposium-2005 (NLS - 5), Vellore Institute of Technology, Vellore, pp.82, December 7-10, 2005.
    
    
21. J. Khanwalkar, R. Arya, S. Kumar, V.B. Tiwari, H.S. Rawat, T.P.S. Nathan,
    “Power supply and associated instrumentation for tunable diode laser system for experiments in High resolution spectroscopy”,
    DAE-BRNS National Laser Symposium-2005 (NLS – 5), Vellore Institute of Technology, Vellore, pp. 95, December 7-10, 2005.
    
    
22.  J. Khanwalkar, R.Arya, T.P.S.Nathan,
    “Temperature controller for diode-pumped solid-state-lasers”,
    National Symposium on Instrumentation (NSI-30), CUSAT, Cochin, pp.161, Novemeber 30-December 2, 2005.
    
    
23. A. Sharma, R. Arya and T.P.S.Nahtan,
    “Kilovolt Pulse Generator with 7 nanosecond fall time for gating electro-optic Q-switch”,
    National Symposium on Instrumentation (NSI-30), CUSAT, Cochin, NSI-30, pp.92, Nov 30-December 2, 2005.
    
    
24. R. Arya, Sajith Kumar, Manoj Kumar, Joy Thomas M. and T.P.S. Nathan,
    “Study of RCD snubber with clamp in a pulsed power source for flash-lamp-pumped solid-state lasers”,
    DAE-BRNS National Laser Symposium -2004 (NLS-4), BARC, Mumbai, pp.187-188, January 10-13, 2005.
    
    
25. S.K. Sah, R. Arya and T.P.S. Nathan,
    "Development of a pulsed power supply for laser flash thermal diffusivity experiments”,
    DAE-BRNS National Laser Symposium -2004 (NLS-4), BARC, Mumbai, pp.789-790, January 10-13, 2005.
    
    
26. Vijay Bhawsar, R.Arya and T.P.S. Nathan,
    “Embedded electronic controller for CW Nd:YAG laser system”,
    DAE-BRNS National Laser Symposium -2004 (NLS-4), BARC, Mumbai, pp.243-244, January 10-13, 2005.
    
    
27.  S.K.Sharma, Nithyaja B., P.K.Mukhopadhyay, K.Rangnathan, R. Arya and T.P.S.Nathan,
    . “Effect of QWP tilt on the shape of intracavity frequency doubled green laser pulse”,
    DAE-BRNS National Laser Symposium -2004 (NLS-4), BARC, Mumbai, pp.216-218, January 10-13, 2005
    
    
28. R.Arya, M. Joy Thomas, T.P.S.Nathan and D.D.Bhawalkar,
    “A novel simmer power supply for flash-lamp-pumped solid-state lasers",
    National Laser Symposium, I.I.T.Kharagpur, pp.147-148, 2003.
    
    
29. Jagriti Khanwalkar, R.Arya, and T.P.S. Nathan,
    “Instrumentation for tunable diode laser”,
    National Symposium on Instrumentation (NSI-28), Pant  Nagar,  pp.268, Novemeber 3-5, 2003.
    
    
30. Vijay Bhawsar, Ashutosh Sharma, R.Arya, and T.P.S. Nathan,
    “A compact high resolution two-channel isolated reference voltage generator for power supplies”,
    National Symposium on Instrumentation (NSI-28), Pant Nagar, pp.268-269, Novemeber 3-5, 2003.
    
    
31. Sajith Kumar, R.Arya, and T.P.S. Nathan,
    “A novel power supply for arc lamp pumped solid state laser”,
    National Symposium on Instrumentation (NSI-28), Pant Nagar, pp.267, Novemeber 3-5, 2003
    
    
32. G.Mundra, A.Choube, M.R.Jathar, R.Arya, S.C.Vishwakarma and T.P.S.Nathan, 
    "Design of 4-Axes Laser Welding Work Station (Machine) for Cardiac Pacemaker"
    National Welding Seminar, NWS-2002, the Science City Auditorium, Kolkata, 2002 (This paper has been adjudged the Winner of KCP Award-2003 for the Second Best Paper on Fabrication in Welding.)
    
    
33. R. Arya, Joy Thomas M., T.P.S. Nathan and D. D. Bhawalkar,
    “Power systems for lasers used in material processing applications”,
    DAE-BRNS Symposium on Power Beams and Materials Processing-2002, BARC, Mumbai, 2002.
    
    
34.  R. Arya, Manoj Kumar, S.K. Sah and T.P.S. Nathan,
    “A compact, versatile power supply for low power CO2 laser”,
    National Laser Symposium-2002, Shri Chitra Insti Trivendrum, November, 2002.
    
    
35. G.Mundra, B.N.Upadhyay, R.K.Jain, P.Mishra, A.Choube, S.C.Vishwakarma, V.Bhavsar, R.Kaul, K.Rangnathan, R.Arya and T.P.S.Nathan
    “Irradiation Capsule Laser Welding Machine”,
    National Laser Symposium-2002, pp.267-268, 2002.
    
    
36. Vijay Shukla, S.Krishnan, Rama Chari, A.Singh, R.Arya and S.M.Oak,
    “An efficient Nd:YAG amplifier for short laser pulses”,
    National Laser Symposium, 1999.
    
    
37. R.Arya, Joy Thomas M., A.G.Bhujle and D.D.Bhawalkar,
    "A compact pulse power source for solid state lasers",
    Fourth Conference on EHV Technology, IISc, Bangalore, July 17-18,1998.  
                                                                         
38.  R.Arya, Joy Thomas M., A.G.Bhujle and D.D.Bhawalkar,
    “A novel trigger system for flash lamp pumped solid state laser power supply”,
    Twenty third National symposium on instrumentation (NSI-23), Birla Institute of Technology, Mesra Ranchi, October 7-10,1998.
    
    
39. R.Arya, C.Rajan and A.G.Bhujle,
    "A compact power supply for nitrogen laser",
    National Laser Symposium, BARC, Bombay, Jan.17-19, 1996.
    
    
40. M.R.Jathar, V.W.Meshram, R.Arya, G.Mundra, K.R. Ramgnathan, T.P..S.Nathan and A.G.Bhujle,
    "Automated Laser Welding Machine For Cardiac Pacemaker",
    International Conference on Automation (ICAUTO-95), SGSITS, Indore, Dec. 12-14, 1995.
    
    
41. R.Arya, S.Krishanan, Sudheer S.K. and A.G.Bhujle,
    "A compact simmer current source for flash lamps",
    National Laser Symposium, IRDE, Dehradun, Feb. 10-14, 1995.
    
    
42. U.Nundy, P.Choudhary, M.Sajeev Mohan and R.Arya,
    "A pulser circuit using magnetic pulse compression",
    National Laser Symposium, CAT, Indore, Jan. 29th - Feb. 1st, 1994.
    
    
43. Y.V.S.T. Sai, T.P.S.Nathan, C.P.Navathe, R.Arya, P.Shryner, G.Mundra, D.K.Kohli, P.Khare, A.S.Rajarao and D.D.Bhawalkar,
    "Development of a CW CO2 laser system (Model C-40) for surgical applications",
    National Symposium on Instrumentation (NSI-16), Cochin University of Science and Technology, Cochin, Nov. 24-27,1991.
    
    
44. Sanjay Kher, Nitin Vyas, R.Arya, M.R.Jathar, B.N.Singh and D.D.Bhawalkar,
    "Design and development of laser uranium analyzer",
    Second IPA/DST symposium on lasers, Banaras Hindu University, Varanasi, Dec. 11-15,1989.
    
    
45. P.Shrivastava, Medha Puranik, Rajesh Arya and P.C.Sharma
    "Microprocessor-based Multi-channel temperature measurement and control",
    Fifth All India Symposium on Instrumentation, Institute of Engineers and Technology, Lucknow, Dec. 28-29, 1987.