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 4/7/2015 5 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 4/7/2015 11 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.