Updates of BNL GdLS BNL NeutrinoNuclear Chemistry Group
Updates of BNL Gd-LS BNL Neutrino/Nuclear Chemistry Group Richard Hahn Scientist Minfang Yeh Scientist Alex Garnov Leader, Senior Associate Post Doc (Group reduced to 3 people. Alex will
Attenuation Length Measurements 1. 1 - and 10 - cm cells in Shimadzu UV-1601 spectrometer (200 – 1100 nm) 2. 1 -m horizontal cell, blue laser system (442 nm) 3. 1. 5 -m vertical pathlength, LED variable wavelength system (350 – 700 nm, working with M. Diwan of BNL Physics) under room light under black light
Gd-LS Attenuation Stability (10 cm cells) Abs = 0. 004 ~ Atten. Length = 10 m
Scintillator Selection UV Abs. 430 Gd Loading d (g/cm 3) Light Yield H atoms‡ per c. c Flash Point PC Yes 0. 889 0. 008/0. 0 Vacuum 1. 504 02 Distil. 1 5. 35 1022 48 C PCH Yes 0. 95 0. 072/0. 0 01 Column 1. 526 0. 46 4. 28 1022 99 C DIN Yes 0. 96 0. 040/0. 0 23 Column 0. 87 3. 27 1022 >140 C PXE Yes, but not stable 0. 985 0. 044/0. 0 22 Column 0. 87 3. 38 1022 167 C LAB Yes 0. 86 0. 001/0. 0 00 Column 1. 482 0. 98 2. 52 1022 130 C 0. 85 0. 002 ~0. 001 N/A ~1. 46 calculated from density. Dodeca No 0. 75 ne (<20%) 0. 001 ~0. 000 N/A 1. 422 Mineral Oil ‡ No before/afte r Purif. Method n 20 ~ 1. 62 – 1. 65 1022 215 C ~ 3. 18 1022 71 C
New Candidate for 13 Experiment • • LAB (Linear Alkyl Benzene) containing side alkyl chains of 10 -13 C atoms; average ~11. 3 atoms. Long attenuation length, low cost, low reactivity, high flash point, and high light yield An ideal scintillator, discovered from our collaborative SNO+/++, that can also be used in 13 experiment. Boiling Point (o. C) 275 - 307 Melting Point (o. C) < -50 Flash Point (o. C) 130 Vapor Pressure (mm. Hg) < 0. 1 mm. Hg @ 20 o. C Vapor Density (Air =1) 8. 1 Solubility in Water Insoluble Molecular Weight 233 – 237 g/mol p. H Not applicable Viscosity 5 – 10 cps @ 20 o. C Evaporation Rate (water =1) Not applicable
LAB Purification
Light Yield of LAB versus PC 3 g/L PBD + 15 mg/L bis-MSB
Optical Spectrum of 0. 2% Gd in 20%PC-80%LAB • Fact: 20%PC-80% LAB mixture is stable for ~ 1. 5 month since synthesis. • Question: Can we load Gd directly into LAB? Answer: Yes!
Optical Comparisons of ~1% Gd in LAB and PC 430 nm • BNL has successfully loaded Gd into 100% LAB • Gd-LAB has much better transparency at < 400 nm and at least ~50% improved optical transparency at 430 nm, compared to Gd-PC
~1% Gd in LAB and PC 430 nm Gd-LAB has much better transparency at < 400 nm and ~20% better optical at 430 nm, compared to Gd-PC
Funding Constraints of the BNL Group: ØThis EOI was. Personnel requested by OHEP. costs ØMy group’s base program comes from DOE/ONP. Ø We took a major hit in FY-06. Currently are barely able to support our existing 3 -person group. ØIt is not at all clear if ONP will give any support for reactor theta-13 work. ØWe are starting to write our new FWP, due in early February for FY-2007 -2009. ØI plan to talk with ONP (Gene Henry) in the next week; also with OHEP to get their input about this issue. h Brookhaven Science Associates
Funding Constraints of the BNL Group: ØWe are involved in other neutrino R&D, II re solar Personnel costs, neutrinos and double beta-decay. Our major thrust is on Metal-loaded LS, with current main emphasis on Gd-LS for theta-13. Ø Other efforts: (a) Compatibility of M-LS with acrylic and other structural materials. (b) Radioactive contaminants, assay and control. ØBasic Questions: Will ONP continue to fund our “base program” with supplementary support for theta-13 from OHEP? Or, will ONP share theta-13 costs with OHEP? Ø Or Horrors! Will ONP cut us significantly? h Brookhaven Science Associates
Funding Constraints of the BNL Group: Personnel costs, III ØIn summary, there is a likely chance that we will not receive ONP funding for postdocs to work on Theta-13. ØWhat to do? Should we ask OHEP for this support? ØBasic annual total cost of a postdoc at BNL is $100 K (includes all overhead costs). ØOur bare minimum need is one new postdoc; two are preferable. h Brookhaven Science Associates
Funding Constraints of the BNL Group: “Materials”costs, ØLet’s not lose sight of the fact that the. IGd-LS tests that we have been doing at BNL involve small Amounts, <1 L batches. ØClearly we want to scale this up to several L, or even more. I am not comfortable basing all of our claims about the quality of the Gd-LS on small samples, especially since our full-scale detector modules will contain 65 tons each. Might we be fooling ourselves? ØCosts for chemicals, materials, and equipment specifically for Gd-LS: Our request in our 2004 proposal was very modest, $28 K. h Brookhaven Science Associates
Funding Constraints of the BNL Group: “Materials”costs, II new ØIs that sufficient for our R&D? We are building Systems at BNL, e. g. , to scale up our Gd-LS production to tens of liters per batch, to measure optical transparency of large volumes, … ØA major question is: do Braidwood people want appreciable amounts of Gd-LS, to do tests independent of the BNL Group, to get data to validate Monte Carlos, … ØSo far, the only request I have is from Ed, for ~10 L for his small-scale prototype at Chicago. ØIs that all? The cost to a large extent depends on your needs. What shall we do? h Brookhaven Science Associates
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