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Message ID: 10288     Entry time: Tue Jul 29 18:58:57 2014
Author: Nichin 
Type: Update 
Category: Computer Scripts / Programs 
Subject: PDFR update and Test run 

The PDFR system's interface and scripts have been updated to include quite a few more features.

On the interface side, there are buttons to open the previous plot for each PD and also a single button to run the scans on all PDs sequentially. The previous plot buttons actually open a softlink that is updated each time a measurement is taken.

Running a scan now pops up a terminal window to show messages that help understand whats going on.

16.png

In the background, the script now takes in the transfer function of the demodulator board in ZPK format and calibrates it out of each measurement. The parameters are given .dat files making it easier to replace the transfer function. (Remember my last elog which showed that the fitting of transfer functions were not really great and that I am going to use it anyway to get the script updated.)  Also, the script now takes the delay in the RF cables and calibrates out that as well. So we no longer have the huge phase variations and the phase related to transimpedance are visible.

A test run was conducted today. Plots attached.

NOTE: The test can be conducted only on REFL 11,33,55,165 , AS55, and POX11.

POY11 has an optical fiber routed from this system, but there is no space to actually illuminate this PD. So it is currently not included in our system, even though there is a button for this.

POP22 has a fiber illuminating it, but its a unknown broadband PD. I do not know it's DC transimpedance or other values. Its just of matter of updating a few files that feed it's parameters into PDFR.

However, for the above PDs, the demodulator boards have been fit to a transfer function and the script is ready to go as soon as the above problems are fixed.

Conclusion: The plots look noisy. But, the transimpedance now resembles the one on 40-m wiki for all the PDs, both the shape and values.

There will be some errors that are induced because of improper demodulator TF fitting. This has to be taken care of eventually.

Work remaining: Create a canonical set of plots for each PD and set them as the baseline. These canonical plots will be plotted along with each measurement for easy comparison.

A well documented manual for the whole system clearly explaining where and how it takes all the parameters into account so that anybody can easy update just the essential information.

Attachment 2: PDFR_testRun_29-07-2014.pdf  230 kB  | Hide | Hide all
PDFR_testRun_29-07-2014.pdf PDFR_testRun_29-07-2014.pdf PDFR_testRun_29-07-2014.pdf PDFR_testRun_29-07-2014.pdf PDFR_testRun_29-07-2014.pdf PDFR_testRun_29-07-2014.pdf
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