update of gd-ls r&d at ihep
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
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Update of Gd-LS R&D at IHEP
Ding Yayun, Zhang Zhiyong, Cao Jun
Institute of High Energy Physics,
Chinese Academy of Sciences
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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 suitable solvents
– to find out the suitable Gd complexes with organic ligands
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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
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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.
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Requirements for the Selected Gd Complexes
– stable enough against hydroylsis
– relatively high solubility in aromatic solvent
– low absorption around 430 nm
– Organophosphorous compounds
– -Diketones
– Carboxylic acids
Three kinds of organic ligands have been used
Choice of Gd Complexes
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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
P OR
R
R
P
O
RR
R
P
RR
R
Ln3+
O
Gd3+
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-Diketone
Acetylacetone (Acac) Chooz-II
Low solubility in the scintillator solvent
HC OC
R
R' CO
CH
O
CR R'
C
O
CH
OC R
R'
CO
Ln3+
_
_
_
Gd3+
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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
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Preparation of Gd-CBX
1. 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
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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, TMHAMeasured by Elemental Analysis,
Vario EI, Elementar Analysensysteme GmbH
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Gd(TMHA)3 can be directly dissolved in LAB
Gd(EHA)3 only can be dissolved in the mixtures of
trimethylbenzene and LAB( or trimethylbenzene and dodecane)
Four Gd-LS samples have been prepared
Gd (g/L) Ligand fluors solvents
1.5 TMHA PPO5g/L
bis-MSB 10mg/LLAB
2.0 TMHA PPO5g/L
bis-MSB 10mg/LLAB
1.5 EHA PPO5g/L
bis-MSB 10mg/LVmesitylene:VLAB=2:8
2.0 EHA PPO5g/L
bis-MSB 10mg/LVmesitylene:VLAB=2:8
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Characteristics of Gd-LS Based on Gd-EHA, TMHA
Pgeneral TU-1901 UV-Vis spectrophotometer
10 cm Quartz Sample Cuvettes
1 、 Absorption Measurements
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A is the absorption at 430 nm
Absorption Spectrum measured by TU-1901
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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.
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sample name
Absorption Measurement Vertical LED System
Abs
@ 430nm
Calculated Attenuation Length/m
Attenuation Length/m
LAB
(unpurified )
0.0053
±0.00028.2±0.3 8.7±0.6
LAB
(filtered)
0.0054
±0.00038.0 ±0.4 9.0±1.0
LAB+PPO
+bis-MSB
(filtered)
0.0062
±0.00017.0±0.1 7.1±0.4
Comparison of two methods for measuring Attenuation Length of the same Liquid samples
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3 、 Stability Test: 2g/L Gd-LS as a Function of Time
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4 、 Light Yield Measurements
Gd (g/L)
Ligand fluors solvents Relative Light Yield
- - PPO5g/L, bis-MSB 10mg/L Vmesitylene:VDodecane=2:8 0.459
- - PPO5g/L, bis-MSB 10mg/L LAB 0.542
1.5 EHA PPO5g/L, bis-MSB 10mg/L Vmesitylene:VLAB=2:8 0.538
2.0 EHA PPO5g/L, bis-MSB 10mg/L Vmesitylene:VLAB=2:8 0.528
1.5 TMHA PPO5g/L, bis-MSB 10mg/L LAB 0.492
2.0 TMHA PPO5g/L, bis-MSB 10mg/L LAB 0.478
relative light yield data = liquid scintillator / anthracene
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5 、 Emission Spectrum measurement
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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
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Thank You!Thank You!