Facility

With the passage of time the need of being independent from the outside market has significantly increased and physics lab is approaching this goal by developing specific expertise and manufacturing skills in the lab. Moreover, making complex circuit on Vero board was time consuming and prone to error. Previously PCB manufacturing was done from Hall road or through chemical etching in the lab. Recently, the Physlab has acquired CNC based CCD PCB machine. The machine is capable of routing and drilling copper boards. The machine works on the principle of isolation milling. The workstation comprises of a dedicated personal computer with driver software and Isocam, vacuum cleaner (for sucking dust while spindle is running) and a power supply unit. We have Tungsten carbide routers of diameter 0.6 mm and drill bits of 1.2 mm, 0.5 mm, 0.3 mm and 3 mm size.

Commercial usage of the facility can also be discussed.

Dielectric Measurements are a basic means of evaluating electronic components and materials. Every material has a unique set of electrical characteristics that are dependent on its dielectric or insulation properties. Accurate measurements of these properties can provide valuable information to ensure an intended application. The dielectric cell is successfully designed and constructed for measuring frequency and temperature dependent dielectric properties of rigid flat materials such as Ceramics, Polymers and composites at elevated temperatures. The cell is classified in vertical and horizontal assembly that can be used up to 300 Degrees C and up to 800 Degrees C respectively.

The cell is made up of two electrodes. One electrode is fixed and the other is movable with a guard ring via a micrometer. The micrometer allows precise measurement of electrode spacing. The guard ring reduces fringe effects to improve measurements. The cell can be connected to LCR meter through probes and is interfaced with computer through software wizard that will allow to control the LCR via DB-9 cable and perform linear or log sweeps over a frequency range 20Hz to 1MHz as well as save the measurement results to a log file.

The Physlab has recently acquired a CNC machine (CNC Lathe Smart 32-T8, manufactured in Taiwan). This will boost the manufacturing capabilities of the Laboratory, making possible the fabrication of high precision components and equipment for scientific research. This is the latest addition to the Physics Lab Workshop. The machine is equipped with Fanuc control.

The Physlab has assembled a low cost energy dispersive X-ray fluorescence (XRF) system to carry out the elemental analysis of different materials. The assembly to place the samples is constructed in the physlab workshop and analysis of different materials is carried out using this XRF system. The XRF system will ease the analysis of materials commonly used in the lab and also help in studying the archeological sites in our city. The XRF system will be used in the Physlab for:

1) Examination and historical coregistration of (a) coinage, (b) manuscripts and (c) metal wear preserved in Lahore’s museums and archeological sites.

2) Quantitative compositional analysis of thin films grown in the lab.

Here is a laboratory experiment dealing with XRF.

With the help of the four probe technique, it is possible to eliminate voltage drops in measurement leads allowing accurate determination of low and medium range resistivities. At the physlab, we have developed sample holders with four needles in the collinear and van der Pauw configurations, for the measurement of electrical resistivities. Equipped with a high temperature oven, close cycle helium cryostat and temperature controllers, we can routinely make measurements from 10 to 780 K. A precision current source and nanovoltmeter are used for the measurements. These computer controlled instruments can be operated in the delta configuration allowing the compensation of thermally induced voltages.