Comparison of gradients obtained using PSplot and Perl Scripts
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Comparison of gradients obtained using PSplot and Perl Scripts Chow, Yeuk Chun UCLA Abstract The gradients of leakage currents against luminosities for SVX and Layer 00 were obtained using web-based PSplot and Perl scripts written by Saverio D’Auria. The data used were between store number 1663 and 2155. The integrated luminosity in this period is 100.3 pb −1 . The two different methods will be described and the results obtained will be compared. Introduction The SVX and Layer 00 are constantly exposed to high dose of radiation. The radiation damage sustained leads to an increase of leakage current in every components of the detector. As it increases, a higher biased voltage will need to be applied to deplete the detector of free charge carriers. Eventually the biased voltage required will exceed the limit that can be supplied and the detector will longer be operational. The gradients of the leakage current are thus important quantities in estimating the longevity of the detector. Two ways of obtaining the gradients are using PSplot or processing the raw data from the online machines with perl scripts. Both methods are described and the numerical results they produced will be compared. PSplot ( http://nucsb03.fnal.gov/cgi-bin/PSPlot ) The parameters used to plot the graphs are as follows (SB0W0L0 was used in this example): Type of plot : ScatterPlot variable for scatter plot-Days Axes for plots: #x bins 10 min x 550 Max x 950 #y bins 10 min y 0 Max y30 Plot options OptSta 0 graphoption P showtitle t titile SB0W0L0 1st variable: Wedge SB0W0 Var Ibias0L0 color cyan fillcolor white Marker 8 Linewidth 3 Scale factor X 1 Y 1 Apply selection cuts: 591 <= Days <=740 AND 80 <= Vbias0L0 <=999 Draw vertical line: 15.2835 Fit function: pol1 For different components the parameters will have to be modified accordingly. A perl script (grabFile) was written to speed up plotting and downloading the graphs. All the .jpg files produced, the perl script and the documented results can be found in fcdflnx2:/cdf/home/yckchow/graphs/ Note that the gradient on the graphs produced are in the unit of µA/ Day so the number have to be multiplied by 150/(1000*100.3) to covert it into unit of µA / nb −1 . Using Perl Scripts The perl script files used are (1) nice_readstores.pl (2) file_scrambler_hdi.pl (3) generate_gnuplot.pl (4) runfits_oop.pl (5) readfits.pl. The raw data from the online machines have to be processed using (1) first. Then 2, 3 , 4 and 5 were run in turn and the final output is a file named “datafile”, it contains for each component, the corresponding gradient and error. All the perl files used and data obtained can be found in (i)fcdflnx2:/cdf/home/yckchow/automation (ii)b0pcucla7:/cdf/home/yckchow/data Comparison The gradients obtained using the two methods are plotted against each other (by Gino Bolla) and is shown below It can be seen that the two methods gave very consistent results they are within 4% of each other. Conclusion It was shown that the two methods agreed very well for most of the component. However, large discrepancies were found in some of the them. For example SB0W0L0, SB0W1L0, SB0W2L4, SB0W3L4, SB0W9L0, SB0W9L2, SB0W3L2. By comparing the jpg file produced by PSplot and the gnuplot graph using the perl script. The conclusion is that for the components in L2 and L4, the discrepancy was caused by the difference in the cutoff voltage used. In SB4W9L2 for example, the range of current plotted was 0-30 using PSplot but it can be seen in the gnuplot graph that the currents was actually in the range 80 – 120 . For L0 the reason for the discrepancies is still unexplained. Although the graph showed that the gradients obtained using the two different methods are very close to each other. But in terms of efficiency and reliability, the perl scripts are recommended since they are quicker and easier to run overall and there will be no need to adjust the scales of cutoff voltage/current used.