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This summer, my job was to add a sixth audio transducer to the Spark Chamber and then modify all the systems that would be influenced by this modification. Also, since the project had not been touched since summer 1999, I had some cleaning to do.
First, I had to clean the plates of the accumulated dust through the years. This was important because the plates have to be perfectly parallel to each other. If a dust particle is lying on a plate, the distance between them at this very spot will be smaller and the spark will happen where the distance is the smallest. Also, some of the connections from the audio transducers to the amplifiers were broken, so I had to change the transducers themselves, P4 and P3. P6 was added at the same time.
The next step was to add the electronics associated to the sixth input, in the acquisition card as well as in the receiving card. This was done using a wire-wrapping tool. A TTL buffer was the only module that was added to the acquisition card. The remaining parts were already designed for six inputs. I just had to make the appropriate connections. The receiving card was slightly modified by using another power source for the +5 V line and the GND. I used the PC power supply instead of the PC bus. A second Lab Tender card was also installed in the PC to process the sixth signal. The connections for it are similar to the ones for the first Lab Tender.
After the electronics was changed, I had to do a little bit of programming to use the new Lab Tender. The version 2.31 of the acquisition program, Acquire, was developped. It now prompts the user for the number of events to acquire and for the output filename, it includes an overwrite protection of the existing data files, it computes the time of the acquisition and most of all it processes a sixth input.
The analysis part of the system is ready to accept the data coming from six inputs. The program Spk was already design to compute up to 8 different input, so no modification had to be done on the program. The first 2002 data are now ready and an alyzed.For further details please consult the logbooks.
Right now, I am finding interesting physical relations between the quantities implied. In order to this, I am using PAW, the CERN application for physical computations.
After this summer, the Spark Chamber will be completely functionnal with six piezzo signals. Also, the data analysis program will give complete trajectories without any ambiguities. The project will then be ready to be used as a laboratory project. The only thing that will need to be done is to take data and analyze them.
