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Update of Gd-LS R&D at IHEP

Update of Gd-LS R&D at IHEP. Ding Yayun, Zhang Zhiyong, Cao Jun. Institute of High Energy Physics, Chinese Academy of Sciences. Quality Requirements for Gd-LS. – long attenuation length – good light yield – chemically compatible with acrylic – stable for several years.

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Update of Gd-LS R&D at IHEP

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  1. Update of Gd-LS R&D at IHEP Ding Yayun, Zhang Zhiyong, Cao Jun Institute of High Energy Physics, Chinese Academy of Sciences

  2. Quality Requirements for Gd-LS – long attenuation length – good light yield – chemically compatible with acrylic – stable for several years Two main concerns in the preparation of Gd-LS – to find out the suitablesolvents – to find out the suitable Gd complexes with organic ligands

  3. Choice of Solvents • pseudocumene, PC and mesitylene • Drawbacks: low flash point • aggressive to acrylic • Linear alkylbenzene, LAB • high light yield, high flash point, low toxicity, cheap • long attenuation length

  4. Linear alkylbenzene , LAB, C10~C13 • Produced by JinLing Petrochemical Limited Corp., SINOPEC Crop. P.R.C • Meet national standards GB/T 5177.5-2002 • Elemental analysis shows: C: 87.3% H: 11.5% (deviation: 1~3%) The most possible average molecular formula is C6H5-C12H25 • Further study about the composition of LAB is ongoing.

  5. Choice of Gd Complexes Requirements for the Selected Gd Complexes – stable enough against hydroylsis – relatively high solubility in aromatic solvent – low absorption around 430 nm Three kinds of organic ligands have been used – Organophosphorous compounds – -Diketones – Carboxylic acids

  6. Gd3+ Organophosphorus Ligands Triethylphosphate (TEP) Triisoamylphosphine Oxide (TiAPO) Dibutylbutylphosponate (DBBP) Tri-n-octylphosphine oxide (TOPO) Di(2-ethylhexyl) phosphate (D2EHP) -Highly soluble in aromatic solvents -Moderate attenuation length

  7. Gd3+ -Diketone Acetylacetone (Acac) Chooz-II Low solubility in the scintillator solvent

  8. Carboxylic acids 2-Methylvaleric acid (2-MVA) 6C BNL, IPCE-RAS, Chooz-II 2-ethylhexanoic acid (EHA) 8C Bicron, Palo Verdo 3, 5, 5-trimethylhexanoic acid (TMHA) 9C MPIK

  9. Preparation of Gd-CBX • Direct synthesis (Bicron, Palo Verdo, Chooz-II) • 1) HA + NH4OH → NH4A + H2O • 2) 3NH4A + GdCl3→ GdA3 + 3NH4Cl 2. Liquid-liquid extraction (BNL, MPIK) Organic phase Water phase

  10. Gd carboxylate complexes synthesized • Gd complexes with 2-ethylhexanoic acid (EHA) white powder • Gd complexes with 3, 5, 5-trimethylhexanoic acid (TMHA) white powder Composition of the complexes Gd-L3 L = EHA, TMHA Measured by Elemental Analysis, Vario EI, Elementar Analysensysteme GmbH

  11. Gd(TMHA)3can be directly dissolved in LAB • Gd(EHA)3only can be dissolved in the mixtures of trimethylbenzene and LAB( or trimethylbenzene and dodecane) Four Gd-LS samples have been prepared

  12. Characteristics of Gd-LS Based on Gd-EHA, TMHA 1、Absorption Measurements Pgeneral TU-1901 UV-Vis spectrophotometer 10 cm Quartz Sample Cuvettes

  13. A is the absorption at 430 nm Absorption Spectrum measured by TU-1901

  14. 2、Attenuation Length Measurements by Vertical LED System • Vertical LED System needs larger volume of sample • Vertical LED System: 1L • UV-Vis spectrophotometer: 40mL • Vertical LED System can obtain more accurate attenuation Length data than ordinary UV-Vis spectrophotometer.

  15. Comparison of two methods for measuring Attenuation Length of the same Liquid samples

  16. 3、Stability Test: 2g/L Gd-LS as a Function of Time

  17. 4、Light Yield Measurements relative light yield data = liquid scintillator / anthracene

  18. 5、Emission Spectrum measurement

  19. Ongoing and Future R&D at IHEP • Continue our long-term stability tests for periods more than 1 year • Study the chemical compatibility of these Gd-LS with the materials that will be used to construct the detector vessel • Develop methods to remove radioactive impurities (10-10g/g) • Mass producition

  20. Thank You!

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