A W thesis

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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

A_W_CAA_apparatus

Y-88 CAA

Run6980_Y88

Run7023_Y88

Run7108_Y88

Run7161_Y88

Run7204_Y88

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.

File:AW Background Noise.pdf

Changed integration limits and re-fit r7235 File:AW Background Noise custom2.pdf

File:AW Background Noise custom3.pdf

All the ROOT fit parameters used to find the background and the resulting peaks. File:Y-88 Fit Log.pdf File:Y-88 Fit Log 2.pdf

Integrating the gaussian of the HpGe detector signal. File:AW Gaussian Integral.pdf

Run7204 Y88 898 signalnoise.png Run7204 Y88 898 signal.png

Run7235 Y88 898 signalnoise.png Run7235 Y88 898 signal.png

Run7236 Y88 898 signalnoise.png Run7236 Y88 898 signal.png

898 keV Signal and Background Noise Table

Run # Area of Signal Area of Background Signal to Noise Ratio
7203 130.17 120.59 1.08
7204 825.34 558.66 1.48
7235 194.38 60.23 3.23
7236 1429.75 436.93 3.27


Run7204 Y88 1836 signalnoise.png Run7204 Y88 1836 signal.png

Run7235 Y88 1836 signalnoise.png Run7235 Y88 1836 signal.png

Run7236 Y88 1836 signalnoise.png Run7236 Y88 1836 signal.png

1836.1 keV Signal and Background Noise Table

Run # Area of Signal Area of Background Signal to Noise Ratio
7203 83.29 24.73 3.37
7204 944.58 101.68 9.29
7235 82.25 20.90 3.94
7236 1849.86 97.64 18.95
[math] f(x)=\frac{A}{\sigma \sqrt{2 \pi}} \textstyle \int_{\mu-\sigma}^{\mu+\sigma} e^{-\frac{1}{2}\left(\frac{x-\mu}{\sigma}\right)^2} \operatorname{d}\!x +B x +C[/math]
[math]T_{1/2}[/math] Trig Signal BackG Subtracted Fit Parameters Signal Area Noise Area SNR
.98 [math]T_{1/2}[/math] sing Run7022 Y88 898 rawsignal fit.png Run7022 Y88 898 signalsub fit.png [math]\mu=[/math] 897.34 +/- 0.0938 [math]\sigma=[/math] 0.750375 A= B= C= 5
coin Run7023 Y88 898 rawsignal fit.png Run7023 Y88 898 signalsub fit.png [math]\mu=[/math] 896.90 +/- 0.0064 [math]\sigma=[/math] 1.00907 A= B= C= 6

Ba-133 CAA

BO-08-22-13


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

AW_ADC_7_Histogram

AW_ADC_3_Histogram


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 [math]E_{expected} - E_{fit} -vs- E_{expected}[/math]

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


PAA_Research