Transcript Hans-LRT2010_082910_2

Radio-Purification of Neodymium
Chloride
Sunej Hans and Minfang Yeh
Chemistry Department, Brookhaven National Laboratory, Upton,
New York
Synthetic Pathway of Neodymium Loaded Liquid
Scintillator
Prerequisites for Neodymium liquid
scintillator
• Radio-purification (cost effect) of NdCl3
• Purified TMHA
• Purified LAB
• Radio-purification of PPO
Comparison of the different Commercially available
Neodymium samples
Sample
Sample mass (g)
Nd mass (g)
Cost (US $)
Density (g/cm3)
Metall Nd2O3
997.8
855.4
$923.00
1.321
Stanford Nd2O3
981.2
841.2
$1,438.00
0.725
Metall NdCl3
100.1
402.9
$1,250.00
1.616
NdCl3 Unpurified
1811.3
728.5
very cheap
1.811
NdCl3 Purified
963.4
387.5
B. T. Cleveland and I. T. Lawson
1.184
Neodymium Purification
• Solvent extraction, ion exchanger or scavenge are conventional
technologies to use; time-consuming and costly.
• Th(OH)4is very insoluble in aqueous (ksp= 10-39at 20oC) solution;
only ~10-50M of [Th4+] at pH~4.
• Solubility of lanthanide hydroxide is >10 orders of magnitude higher
than Th(OH)4.
• Self-scavenge (lanthanide itself) method can be used to remove Th
(and other isotopes) by adjusting pH and filtration
• This method can be incorporated into the M-LS production system;
NO additional chemicals (secondary contamination) or exchange
resin are added into the solution
• A simple, self-controllable method that saves time and cost
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Self-scavenging method
Gd(OH)3is the most
insoluble in all
lanthanide series
If it works, all
lanthanides
(including Nd)
should work
-39
Th
6
M. Yeh, J.B. Cumming, S. Hans, R.L. Hahn, “Purification of lanthanides for large neutrino detectors: Thorium removal from gadolinium chloride,” Nuclear
Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol 618, pp 124-130, 2010.
Th and Bi are removed
100% after pH 5.8
GdCl3 selected for
Th-229 spike
experiment
Using this tech.
1Kg of NdCl3 was
purified
Pure NdCl3 was
sent to Bruce for
Radioactive
counting
Results were very
promising
Neodymium samples Analysis with SNOLAB
Ge detector
138La
176Lu
40K
227Ac
214Bi
208Tl
Sample
(μg La/g Nd) (μg Lu/g Nd) (μg K/g Nd) (μBq/g Nd) (μBq/g Nd)
(μBq/g Nd)
Nd2O3 Metall
< 0.56
0.15 ± 0.01
2.1 ± 0.7
4.2 ± 0.8
Nd2O3 Stanford
< 0.54
< 0.08
1.6 ± 0.9
11.6 ± 1.5
NdCl3 Metall
< 1.0
NdCl3 unpur.
480 ± 30
3.1 ± 0.2
NdCl3 purified
< 0.43
0.12 ± 0.02
Tolerable
0.5
0.40 ± 0.23
0.49 ± 0.30 3.1 ± 2.1
0.16 ± 0.02
0.1
< 2.0
1.6 ± 0.6
< 4.8
3.5 ± 1.6
11.2 ± 2.0
6.0 ± 0.9
183 ± 19
18.5 ± 3.5
190 ± 9
25 ± 3
< 6.2
∼0.08
2.7
3.0 ± 1.9
0.21
Recent γ activity measurements of several high-purity Nd samples with the SNOLAB Ge detector
B. T. Cleveland and I. T. Lawson
SNOLAB
Sunej Hans and Minfang Yeh
Brookhaven National Laboratory
1.8 ± 1.5
3.4 × 10−5
Characterization using XRF
• Qantitative analysis of the impure
and pure lead to only 1% loss
• This small Loss can still save us a
lots of money since the impure one
is a lot more cheaper than the
ultra purity one
Gamma activity measurement of
purified Neodymium sample
• BNL purification was very successful in
removing rare earth radioactive elements
• Purification also removed 227Ac and 214Bi
• 208Tl activity was lowered as well by a factor of
100
• BNL is capable of optimizing the purification
procedure which could bring down or remove
the undesired elements even to further down
limits.
All the activity measurements were done by B.T. Cleveland
Ahha___Bonus Point
Optical transmission >300nm is greatly
Improved
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Expanded UV (1cm) plot for Nd-LAB
Light Yield measurement
Nitrogen purged sample has 16% more light yield
Conclusion
• Self-scavenging is proven to be working effectively
• Data shows the very promising results of radio-purification for
NdCl3
• Th and Bi can be removed from the lanthanide (Nd) at 100%
during the Nd-LS production scheme
• Photon production measurements were compared for sample
with the nitrogenated samples. Measurements were done using
gamma source Cs-137.
• Quality of the Neodymium sample can be further improved by
optimizing the purification conditions
Acknowledgements
•
•
•
•
Dr. Minfang Yeh
Dr. James Cumming
Dr. Liangming Hu
Dr. Richard Hahn
• Neutrino group in BNL
Richard Rosero
Wanda Beriguete
Wai Ting Chan
Dr. Jonny Goett
Dr. Pankaj Sinha
Research sponsored by the U.S. Department of Energy, Office of Nuclear Physics
and Office of High Energy Physics, under contract with Brookhaven National
Laboratory – Brookhaven Science Associates.