Closing remark Weiguo Li, IHEP 9 th ACFA workshop and GDE Meeting Feb. 7, 2007 IHEP, Beijing.
Update of Gd-LS R&D at IHEP
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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
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 Presentation
Transcript of 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
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
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
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.
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
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+
-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+
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
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
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
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
Characteristics of Gd-LS Based on Gd-EHA, TMHA
Pgeneral TU-1901 UV-Vis spectrophotometer
10 cm Quartz Sample Cuvettes
1 、 Absorption Measurements
A is the absorption at 430 nm
Absorption Spectrum measured by TU-1901
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.
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
3 、 Stability Test: 2g/L Gd-LS as a Function of Time
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
5 、 Emission Spectrum measurement
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
Thank You!Thank You!
