Post on 05-Jan-2016
description
transcript
GERDA meeting Dubna 27-29/06/2005
LNGS Chemistry Service S. Nisi
Natural Ge crystal contamination measurement and Isotopic ratio
determination by ICP-MS
Analysis method
• Ge crystal dissolution HNO3+HF+H2O 1:1:1
• Dilution of samples and spiked samples preparation to check the procedure
• Measurement of contamination and isotopic ratio by ICP-MS Agilent Technologies model 7500a (quadrupole mass analyzer)
ICP-MS in the clean room at LNGS
Interference on contamination measurement
ElementInterferenc
eElement
Interference
11B 10B1H, 22Ne++ N Air
27Al 31P15N16O, 30Si1H
69Ga71Ga 70Ge1H
75As 74Ge1H
113In115In
73Ge40Ar121Sb
205Tl 209Bi
232Th 238U
Ge93 13196 contamination resultsGe93 13196 Spike
Element Ge93 13196ppm
Spike conc ppm
Meas. Conc ppm
11B <0,01 <0,0127Al 0,27 0,2 0,32
31P <2 16,5 39K <5 42 34
69Ga 0,034 0,032115In 0,014 0,1
121Sb 0,001 0,01 0,025205Tl <0,0021 0,01 0,0089209Bi <0,0019 <0,0018232Th <0,0016 0,01 0,0089238U <0,0015 0,01 0,0092
Ge124 11888 contamination results
Ge124 11888 Spike
Element Ge124 11888ppm
Spike conc ppm
Meas. Conc ppm
11B <0,01 <0,0127Al 0,22 0,2 0,3531P <2 16,5 39K <5 42 33
69Ga 0,031 0,033115In 0,0038 0,13
121Sb 0,0013 0,01 0,009205Tl <0,0019 0,01 0,0093209Bi <0,0016 <0,0018232Th <0,0014 0,01 0,009238U <0,0013 0,01 0,0096
Ge crystal contamination comparison
Element nat Ge X8ppm
Ge93 13196 ppm
Ge12411888
ppm11B <0,01 <0,01 <0,01
27Al 0,32 0,27 0,2231P <2 <2 <239K <5 <5 <5
69Ga 0,039 0,034 0,031115In 0,006 0,014 0,0038
121Sb 0,0036 0,001 0,0013205Tl <0,0021 <0,0021 <0,0019209Bi <0,0018 <0,0019 <0,0016232Th <0,0015 <0,0016 <0,0014238U <0,0014 <0,0015 <0,0013
Ge isotopic measurement for GNO
Ge70%
Ge72%
Ge73%
Ge74%
Ge76%
Carrier 70Ge
96,47
96,784
1,14
1,090
0,35
0,320
1,46
1,316
0,57
0,490
Carrier 72Ge
0,36
0,355
98,54
98,609
0,23
0,223
0,73
0,683
0,14
0,129
Carrier 74Ge
0,42
0,444
0,64
0,639
0,23
0,230
98,5
98,486
0,21
0,201
BLUE VALUE=LNGS measure carried out by ICP-MS (quadrupole mass analyzer)RED VALUE=MC-ICP-MS (double focusing-multicollector) carried out from ITU of JRC Karlsrhue
Ge crystal isotopic ratio measurement
GeX8%
Ge93 13196%
Ge124 11888
%
70Ge 19,08+/-0,10 19,14 +/-0,07 19,18 +/-0,09
72Ge 27,00 +/-0,13 26,95 +/-0,14 26,80 +/-0,09
73Ge 7,81 +/-0,04 7,76 +/-0,04 7,82 +/-0,07
74Ge 37,58 +/-0,21 37,63 +/-0,13 37,61 +/-0,24
76Ge 8,53 +/-0,10 8,52 +/-0,05 8,59 +/-0,05
Conclusion
• Concerning the contamination measurement of Ge crystal could be possible a little improvement (2or3 factor) of the sensitivity for some elements but we are close to the DL
• About the isotopic composition will be possible measure the enriched crystal with the same accuracy and precision