Monthly Archives: February 2017

Echos and power supply

Since we have a pulse visible on an oscilloscope, we can go to the next step: having an echo using the probe. Unfortunately, some problems remain.

The first ones are concerning the probe itself. We do not know which pin of the motor’s connectors should be connected, we must insert linseed oil in the probe, connect the BNC connector to the pulser and understand why the impedance of the probe measured with a multimeter is only 6 ohms. The last problem is concerning the power supply: we need a continuous 100V.

Concerning the linseed oil and the BNC connector, we easily found a way to solve these problems (we found the connector in the LISA and the linseed oil at home). For the impedance, our colleague Luc on the slack (the one who sold us the probe) explained that the impedance is a imaginary one, so it’s high only when a high frequency voltage is applied to it. We are still looking for the pins connections.

We can not use the probe for now, so we sent our pulse in the oscilloscope (too see it), regain the signal (the echo of the oscilloscope) with the same cable and then connect the output of the echo (the TLVout) to the oscilloscope again. Here is the result:

We found the power supply (0-500V continuous) in the electronics laboratories. Using it, we can obtain a scalable pulse visible on a oscilloscope.

The next step is to use the probe and do the firsts tests with it.

How to get a pulse

Now that we have our different components, we can begin our work. The first step aims to learn how to use the pulser and produce a visible pulse on an oscilloscope.  In that purpose, our professor Mr Debeir allowed us to work in the LISA research service and provided the needed equipment such as oscilloscope and wires.

Technical information about the pulser were obtained from a website given by the manufacturer. We rapidly found the “how to start” section, explaining the first steps to obtain a simple pulse.

Here is the menu that defines the parameters of the pulse:

We used a protoboard for the voltage source and the assembly. The final result and the obtained pulse are shown on the following picture.