Home Laser Controls & Instrumentation Division
Automation of Systems & Laboratory Experiments
Automation of BEC Experiments and Atom Chip MOT Experiments
A Bose–Einstein condensate (BEC) state of the matter is generated when a dilute gas of bosons confined in an external potential is cooled to very low temperature in the range of few hundred nK to few μK. In order to achieve BEC, the precise control of multiple devices such as Acousto Optic Modulators, RF synthesizer, magnet power supplies, camera trigger etc. is needed which operate synchronously. We have designed a computer controlled PCI FPGA card based automation system in LabVIEW with timing resolution of 1 µs. The time critical synchronization with timing jitter of 25ns(max) between 14 such control signals is achieved. A module with 7 DAQ cards is developed to translate the timing signals to appropriate voltages and drive capability as per channel requirement. The target program runs on FPGA card and generate timing signals and host program runs on PC and provides GUI for experiments.
Atom chip controller experiments also require 8 digital and 14 analog signals( 6 isolated + 8 with line drivers) to be generated in synchronisation. NI 7841R card with onboard FPGA, digital outputs as well as analog outputs is used to generate fast timing and analog ramping signals. A module consisting of driving hardware (4 cards) was developed. FPGA ensures parallelism and reliability. The software provides user friendly GUI for experiments.
Automation of Ion-Beam Sputtering System
An Ion-Beam Sputtering (IBS) system has been developed by ISUD for preparing thin films and multilayers of various elements, alloys and compounds. The fabrication facility involves deposition of various layer pairs of different materials in a controlled environment. Inhouse developed target and shutter position control module and mass flow controller readout module are deployed. System has other instruments like ion deposition controller, gun controller, pressure gauge, vacuum gauge for remote interface.
Automation software was developed in Labview to facilitate user to fabricate 100s of layer pairs of selected materials in an automated fashion. The software provides multilayer and monolayer deposition and also fixed thickness or fixed time deposition. It is observed that human errors occurring in the sample preparation process due to fatigue of operator and lack of timely action are totally eliminated. A good degree of repeatability in sample quality is observed. This automation also saves a great deal of time. Earlier dedicated man power was required which is no longer mandatory as sample preparation process can be left unattended. The rate of production of usable samples has greatly increased.
Supervisory control system for Ion Assisted Sputter Deposition System (IASDS)
In sputtering, material to be deposited is first sputtered (atomized) by ion bombardment in a plasma and there by transformed to vapour phase. The particle vapour is then deposited as a thin film on the substrate to be coated. The system is pumped with turbo molecular pump and backed by rotary pump. This sputter unit is equipped with two magnetron guns. RF, DC, pulse DC power can applied to the individual magnetron. Sputtering of single material, co-sputtering of two materials, sequential sputtering of two materials and reactive sputtering (with gas mixtures) can be carried out in the system. Each Material thickness can be monitored independently with a quartz crystal monitor. The In house developed sputtering system provides versatile options to meet many deposition requirements like multilayer optical coatings, thin film research, magnetic devices etc.
An OMRON make CPU CJ2M/CPU13 with RS232 and USB interface PLC based control system is under development for IASDS. This system will facilitate operation in remote mode( through PC) and local mode(through local panel). The system has the capability of 128 nos. of digital inputs, 128 nos. of digital outputs, 24-channel 12-bit analog inputs/outputs to control remotely interfaced devices. For Graphical User interface Labview is used. As Labview OPC server supports OMRON make PLC CPU CJ2M/CPU13.
Automated Test Bench for Accelerator Magnet Power supplies
Automated Test Bench (ATB) has been developed and installed at Switch Mode Power Convertor Lab, Power Converters Division, RRCAT. It consists of a control interface module CIM, DCCT racks, oscilloscope, data logger, master patch panel and a computer. Automation software can configure instruments, acquire data, analyze steady state response, transient response, stability and also perform accelerated testing of power convertor. The ATB performs all tests automatically with minimal manual intervention. After completion of scheduled tests, a detailed report is generated for future reference.
Automation Software for Characterisation of Femtosecond Laser Pulses using Autocorrelation and FROG
Two techniques namely auto-correlation and FROG (Frequency Resolved Optical Gating) are most widely employed to determine pulse characteristics.The laser pulse itself is used to measure the response using nonlinear optical techniques. Intensity autocorrelation is a simple technique to measure pulse duration. FROG is relatively advanced technique which provides phase information in addition to the information obtained by intensity autocorrelation.
In order to characterize these pulses a setup consisting of an optical setup and relevant instrumentation was developed. Automation software which runs on an industrial computer (IPC) was developed in Labview in order to take measurements and present results. The automation process involves the control and monitoring of the spectrometer, photodiode and delay stages in order to characterize the pulse in real time.
Automation Software for Femtosecond Laser Pulse Shaping Experiments
Modulated femtosecond laser pulses are used in many ultrafast spectroscopy experiments to control and study the molecular photo-processes. The pulse shaping experimental setup requires a spatial light modulator (SLM) to modulate the laser pulse and a spectrometer to record the spectrum of the laser pulse. We have developed PC based automation software in Labview to generate desired function shape from list of functions like constant voltage, gaussian, parabola, triangle, well and step. This pattern is then applied to SLM. An external pattern can also be given from a file, if user wants to use some customized function input other than provided functions.
Automation of Photoluminescence Experiment
Photoluminescence study of semiconductor material especially nitride semiconductor is carried out by semiconductor Physics and devices lab. Software aims to provide parameter control of Monochromator, Laser, and PMT and experiment procedure. Graphical user interface is developed to facilitate the display of experiment data, state of experiment and analysis of data.
Automation of Magneto optic Kerr Effect Experiment
Software is developed to carry out MOKE experiment. It is used to control laser, magnet power supply and detection system viz. Lock-In Amplifier. The data is logged from various subsystems and presented in the form of waveform for analysis.
Automation of Opto-Galvanic Spectroscopy experiment:
A computerized system has been developed for automation of opto-galvanic spectroscopy experiments conducted using in-house developed copper vapour pumped tuneable dye laser at RRCAT. In this experiment precise tuning of dye laser and measurement of opto-galvanic signal are required to be carried out. Automated tuning and scanning of dye laser is carried out by interfacing of precise movement controlled translation stage through USB based multifunction card and wavelength meter. Photodiode captured the opto galvanic signal and coerced it in to electrical signal which is further processed using boxcar averager. The output of boxcar averager is acquired using USB based analog input card. Software with Graphical user interface is developed using Lab-View which provides monitoring of opto galvanic signal intensity with respect to wavelength, recording of wavelength and intensity data for further analysis, settings for control parameters of translation stage, wavelength input. Wavelength scanning and tuning setup is also being used for wavelength stabilization of dye laser.
Data Acquisition and Control System for INDUS1-BL4 Experiments
A data acquisition and control system has been developed for automation of experiments conducted on the reflectivity beamline of INDUS-1 accelerator for study of multilayer mirrors. The beamline has various subsystems like monochromator & encoder for selecting desired wavelength for experiments, goniometer consisting of three-axis motion, beam current monitors, ring current monitor, filter selector etc. These instruments are to be controlled & monitored for performing experiments on the beamline. The software developed provides complete automation of four categories of experiments involving continuous scan( simultaneous movement of sample and detector maintaining theta-2theta correspondence), wavelength scan, angle scan and time scan. It provides control of goniometer movement separately for alignment and initial setup of experiment. The user has facility to view & store online plots of experiments. These experiments are carried out with high degree of precision and repeatability.
Automation Software for Resonance Ultrasonic Spectroscopy Experiments
Data Acquisition Software was developed for conducting resonance spectroscopy experiments being conducted by MAASD. The system consists of SR-844 lockin amplifier, SR DS-345 function generator and Lakeshore temperature controller. A user friendly GUI with facility of frequency scanning, lockin and temperatures readouts, online graphing and data logging was developed.