DeepBlueMarin 04222013

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Irradiation of Silver coins from Deep Blue Marin performed on April 22, 2013

Sultan's Report

File:SultansDBM Report 2013.doc

Large Coin

Large Coin mass =6.8921 g

Medium Coin mass =4.628 g

Small coin mass= 6.9325 g

Raw Spectrum

04222013 LargeCoin Raw.png


04222013 LargeCoin Cal.png 04222013 LargeCoin RawMainPeak.png 04222013 LargeCoin CalMainPeak.png
Linear fit using several sources Zoom in to the most intense line The most intense line seems to be from positron annihilation

Energy Calibrated spectrum

04222013 LargeCoin EnergySpectrum.png

Peak Ratios

Ratio of 511 and

Silver lines
Coin Size 511/451 ratio 511/748 ratio 511/1046 ratio
Large 87740/6639 =13.2 87740/2962=29.6 87740/2803 = 31.3
Medium 31950/2938 =10.9 31950/1239 =25.8 31950/1283=24.9
Small 87090/8184=10.6 87090/3790 =22.98 87090/3578=24.34

Gold lines

Consider the neutron knock out reaction on Gold

[math]{197 \atop\; }Au (\gamma,n){196 \atop \; }Au[/math]

Au-196 decays with a half life 6.183 days of by electron capture to Platinum (Pt-196) 92% of the time.

There are two dominant photon energies of 333.03 keV and 355.73 keV. 67% of the time Au-196 goes to the 2+ excited state of Pt-196 after 34.15 ps . 24.7% of the time it decays to the next higher energy 2+ state of Pt-196 after 33.8 ps and then proceeds to emitt a 333.03 keV photon as it transitions to the lower 2+ state where it will emitt a 355.73 keV photon on its way to the ground state.

The spectra below show a clear peak at a photon energy of 356 keV but the signal at 333 keV is less convincing. The peak fit near the 333 keV energy has a Guassian mean of 332. Perhaps there are two different photon energies in the 33 keV region, one at 332 and the other at 333.5.

GoldLinesS333 04222013.png

Coin Size 333 keV 356 keV 333/356 ratio
Large L333 04222013.png L356 04222013.png 5397/3672=1.47
Medium M333 04222013.png M356 04222013.png 2062/1432=1.44
Small S333 04222013.png S356 04222013.png 5552/3956 =1.40

Rate normalized spectrum

Missing Peaks

All three coins were irradiated for 1 hour on 4/22/2013 starting at 11:19 am.

The photon spectrum was measured separately for each coin 5 hours after the activation.

The Large coin spectrum was measured on 4/22/2013 from 17:07:34 until 17:19:17. (livetime = 657.476 second)

The Medium coin on the same day 4/22/2013 from 17:20:50 until 17:37:18. (livetime = 298.611 second)

The small coin on the same day from 17:38 until 17:53:09. (lifetime = 823.458)

388 keV line

A 657 second measurement at 17:07 on 4/22/2013 (irradiation was done from 11:19 until 12:19 the same day)

The Large coin has a line at 388 keV but the small or medium does not.

388 04222013.png

A 141453 second measurement performed 19 days later on 5/11/2013.

511 05112013.png388 05112013.pngZoomed388 05112013.png

Possible Isotope that produce this line are

Ce-135(17.7 hr) ,Sr-87m(2.8 hr), Y-87(79.8 hr), Hg-195m (41.6 hr)

1365 keV line ?

The Large coin has a line at 1365 keV but the small or medium does not.

1365 04222013.png

Possible Isotope that produce this line are


Relative to Nickel

Experimental Setup

DeepBluePAASetup 04222013.png

Nickel counts

Nickel (1) It was in front of the stack. It was counted on April 22,2013. Counting started at 16:53:44 and stopped at 17:04:41.

Nickel (2) It was in the back of the stack. It was counted on April 22,2013. Counting started at 16:41:30 and stopped at 16:52:43.

he measurement was done in position K. The gamma line used for measurement was 1378 KeV and corresponding detector efficiency for this energy and position was 0.0003227 .The half live of Ni-57 is 36 hours.

Ni(1) 0.153 grams, 2.949 uCi

Ni(2) 0.161 g 2.582 uCi

Detection Limits

[math]D_L = \frac{2 I_c S_b}{Y}[/math]

Y = total count

[math]I_C[/math] = concentraion

[math]S_B[/math] = standard deviaiton