Difference between revisions of "A W thesis"
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[[File:AW_Background_Noise_custom2.pdf]] | [[File:AW_Background_Noise_custom2.pdf]] | ||
Revision as of 21:18, 31 July 2014
Introduction
Methods of determining atomic concentration in Material
Neutron Activation Analysis (NAA)
Inductively coupled plasma mass spectrometry(ICP-MS)
Inductively coupled plasma atomic emission spectroscopy(ICP-OES)
Atomic Absorption Spectrometry (multi-element AAS)
Particle-induced X-ray Emission (PIXE)
Another method, uses X-ray from a synchrotron light source and look at the de-excitation of atomic electrons to measure the atomic number. Reports are that they can measure pico-gram quantities.
table of detection limits -vs- Method
Coincidence Counting Setup
Y-88 CAA
Background subtraction
Do the fit:
get parameters for line
Then fill 1 histogram with line
Then subtract
TH1F *coin1=new TH1F("coin1","coin1",30,1800,1860);
ntuple->Draw("ADC7*0.604963-49.7001 >>coin1")
TH1F *lin1=new TH1F("lin1","line1",30,1800,1860);
for(int i=1800;i<1861;i++){
lin1->Fill(i,-2028+1.12*i)
}
TH1F *sub1=new TH1F("sub1","sub1",30,1800,1860);
sub1->Add(coin1,1);
sub1->Add(lin1,-1);
sub1->Draw();
A pdf of the Mathematica notebook used to calculate background area, gaussian area, and plot signal/noise vs. activity.
Changed integration limits and re-fit r7235 File:AW Background Noise custom2.pdf
All the ROOT fit parameters used to find the background and the resulting peaks. File:Y-88 Fit Log.pdf
Ba-133 CAA
Useful commands
Converting CODA data file to ROOT
make sure the CODA and ROOT environmental variables are setup by source the following scripts
source ~/CODA/setup
source ~/ROOT/root/bin/thisroot.csh
Now change to the data subdirectory and execute the program to convert the data file to root
cd /data
~/CODA/CODAreader/ROOT_V5.30/V785V792/evio2nt -fr6994.dat > /dev/null
rename the file so it has the .root extension allowing ROOT to identify it in the browser
mv r6994 r6994.root
Calibration work
System's intrinsic err
Plot calibration parameters as a function of time
determine the variance of the parameters using several (>20) fits
Impact of higher order fits
Plot
Variance comes from several fits,.
Compare uncertainty when fit is E-vs-Channe to Channel-vs-E
Probably should use %error for the weighting
Concentration measurement
A comparison of the measure concentrations using singles and coincidence counting