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Laboratory Studies on the Removal of Radon-Born Lead from KamLAND's Organic Liquid Scintillator  [PDF]
G. Keefer,C. Grant,A. Piepke,T. Ebihara,H. Ikeda,Y. Kishimoto,Y. Kibe,Y. Koseki,M. Ogawa,J. Shirai,S. Takeuchi,C. Mauger,C. Zhang,G. Schweitzer,B. E. Berger,S. Dazeley,M. P. Decowski,J. A. Detwiler,Z. Djurcic,D. A. Dwyer,Y. Efremenko,S. Enomoto,S. J. Freedman,B. K. Fujikawa,K. Furuno,A. Gando,Y. Gando,G. Gratta,S. Hatakeyama,K. M. Heeger,L. Hsu,K. Ichimura,K. Inoue,T. Iwamoto,Y. Kamyshkov,H. J. Karwowski,M. Koga,A. Kozlov,C. E. Lane,J. G. Learned,J. Maricic,D. M. Marko,S. Matsuno,D. McKee,R. D. McKeown,T. Miletic,T. Mitsui,M. Motoki,K. Nakajima,K. Nakajima,K. Nakamura,T. O'Donnell,H. Ogawa,F. Piquemal,J. -S. Ricol,I. Shimizu,F. Suekane,A. Suzuki,R. Svoboda,O. Tajima,Y. Takemoto,K. Tamae,K. Tolich,W. Tornow,Hideki Watanabe,Hiroko Watanabe,L. A. Winslow,S. Yoshida,for the KamLAND Collaboration
Physics , 2013,
Abstract: The removal of radioactivity from liquid scintillator has been studied in preparation of a low background phase of KamLAND. This paper describes the methods and techniques developed to measure and efficiently extract radon decay products from liquid scintillator. We report the radio-isotope reduction factors obtained when applying various extraction methods. During this study, distillation was identified as the most efficient method for removing radon daughters from liquid scintillator.
Novel Microbial Consortium for Laboratory Scale Lead Removal from City Effluent  [PDF]
Sanhita Chowdhury,Ashoke Ranjan Thakur,Shaon Ray Chaudhuri
Journal of Environmental Science and Technology , 2011,
Abstract: n the cells. Scanning Electron Micrographs showed distinct cytoskeleton changes of the cell in presence of metals. Bioremedial package was developed under immobilized condition both with pure isolates as well as mixed consortia for treating heavy metal containing waste water. Efficiency of Lead removal was measured using atomic absorption spectroscopy. All the isolates were found to accumulate metals to different extent. Laboratory scale bioremediation study indicated effective lead removal by immobilized consortium as well as individual strains. The mixed consortium removed 83.68% metal from distilled water and 94.4% from Bheri water both supplemented with 5 mM lead nitrate salt, within 48 h.
Comparative Analysis of Oven-dried and Non-growing Strains of Aspergillus niger for the Removal of Lead under Laboratory Conditions  [PDF]
Ali Abbas Qazilbash,Rani Faryal,Ayesha Tabasum,Asima Lodhi
International Journal of Botany , 2006,
Abstract: Over the years, with the active spread and development of the industries, heavy metals, which are either used, or produced, as by-products, by numerous manufacturing, industrial, refining and mining processes, have become ubiquitous, persistent environmental pollutants. Bioremediation is a cost-effective technology that may be used to remove a variety of pollutants and contaminated sites. This study was designed to compare the capabilities of identified Aspergillus niger strains in the oven-dried (dead) and non-growing (living) forms to adsorb Lead (Pb) from SDB media containing the HM under optimized laboratory conditions using the shake-flask incubation method. Aspergillus niger showed a higher percentage of Pb adsorption in the oven-dried, as compared to the non-growing state. Furthermore, the adsorption by oven-dried strains was also high at higher concentrations of the heavy metal, whereas adsorption of Pb effectively took place at the low concentration levels for the non-growing strains. Analysis of the correlation matrices showed significant positive correlation between strains at high Pb concentrations under the oven-dried condition and significant positive correlation at low Pb concentrations under the non-growing conditions. The percentage Pb adsorption of both strains under oven-dried conditions was over 90% for the concentration range of 100-500 ppm, with the highest being 99.95% at 500 ppm for strain NP 18 after 80 min of incubation. Furthermore, for the non-growing strains this maximum adsorption was achieved for the concentration range of 100-300 ppm and that too was 96.37% achieved by strain NP 17 at 300 ppm concentration after 30 min, after which the toxic effects of the HM on the live fungal strains diminished their capacity to adsorb the metal. When comparing the two biotreatment regimens of oven-dried fungal biomass, verses the use of non-growing pellets of fungi, there is overwhelming evidence to support the use of the former as a method to removal HM contamination from polluted sites, particularly at high concentration levels.
Development of a Gd Loaded Liquid Scintillator for Electron Anti-Neutrino Spectroscopy  [PDF]
Andreas G. Piepke,S. Wayne Moser,Vladimir M. Novikov
Physics , 1999, DOI: 10.1016/S0168-9002(99)00530-6
Abstract: We report on the development and deployment of 11.3 tons of 0.1% Gd loaded liquid scintillator used in the Palo Verde reactor neutrino oscillation experiment. We discuss the chemical composition, properties, and stability of the scintillator elaborating on the details of the scintillator preparation crucial for obtaining a good scintillator quality and stability.
Measurement of the liquid scintillator nonlinear energy response to electron  [PDF]
Fei-Hong Zhang,Bo-Xiang Yu,Wei Hu,Ma-Sheng Yang,Guo-Fu Cao,Jun Cao,Li Zhou
Physics , 2014, DOI: 10.1088/1674-1137/39/1/016003
Abstract: Nonlinearity of the liquid scintillator energy response is a key to measuring the neutrino energy spectrum in reactor neutrino experiments such as Daya Bay and JUNO. We measured in laboratory the nonlinearity of the Linear Alkyl Benzene based liquid scintillator, which is used in Daya Bay and will be used in JUNO, via Compton scattering process. By tagging the scattered gamma from the liquid scintillator sample simultaneously at seven angles, the instability of the system was largely cancelled. The accurately measured nonlinearity will improve the precision of the $\theta_{13}$, $\Delta m^2$, and reactor neutrino spectrum measurements at Daya Bay.
On the level of background in underground muon measurements with plastic scintillator counters  [PDF]
V. I. Volchenko,G. V. Volchenko,E. V. Akhrameev,L. B. Bezrukov,I. M. Dzaparova,I. Sh. Davitashvili,T. Enqvist,H. Fynbo,Zh. Sh. Guliev,L. V. Inzhechik,A. O. Izmaylov,J. Joutsenvaara,M. M. Khabibullin,A. N. Khotjantsev,Yu. G. Kudenko,P. Kuusiniemi,B. K. Lubsandorzhiev,O. V. Mineev,V. B. Petkov,R. V. Poleshuk,B. A. M. Shaibonov,J. Sarkamo,A. T. Shaykhiev,W. Trzaska,A. F. Yanin,N. V. Yershov
Physics , 2008,
Abstract: In this short note we present results of background measurements carried out with a polystyrene based cast plastic 12.0x12.0x3.0 cm^3 size scintillator counter with a wavelength shifting fibre and a multi-pixel Geiger mode avalanche photodiode readout in the Baksan underground laboratory at a depth of 200 meters of water equivalent. The total counting rate of the scintillator counter measured at this depth and at a threshold corresponding to ~0.37 of a minimum ionizing particle is approximately 1.3 Hz.
Performances and stability of a 2.4 ton Gd organic liquid scintillator target for antineutrino detection  [PDF]
I. R. Barabanov,L. B. Bezrukov,C. Cattadori,N. A. Danilov,A. Di Vacri,Yu. S. Krilov,L. Ioannucci,E. A. Yanovich,M. Aglietta,A. Bonardi,G. Bruno,W. Fulgione,E. Kemp,A. S. Malguin,A. Porta,M. Selvi,for the LVD Collaboration
Physics , 2008, DOI: 10.1088/1748-0221/5/04/P04001
Abstract: In this work we report the performances and the chemical and physical properties of a (2 x 1.2) ton organic liquid scintillator target doped with Gd up to ~0.1%, and the results of a 2 year long stability survey. In particular we have monitored the amount of both Gd and primary fluor actually in solution, the optical and fluorescent properties of the Gd-doped liquid scintillator (GdLS) and its performances as a neutron detector, namely neutron capture efficiency and average capture time. The experimental survey is ongoing, the target being continuously monitored. After two years from the doping time the performances of the Gd-doped liquid scintillator do not show any hint of degradation and instability; this conclusion comes both from the laboratory measurements and from the "in-tank" measurements. This is the largest stable Gd-doped organic liquid scintillator target ever produced and continuously operated for a long period.
Evaluation of the Neutron Background in a Direct WIMP Detector with Neutron Veto System Based on Gd-doped Liquid Scintillator  [PDF]
Ye Xu,XiangPan Ji,ZeLong Liu,DanNing Di,HaoKai Sun,Yu Lei
Physics , 2010, DOI: 10.1088/1475-7516/2011/06/009
Abstract: A direct WIMP (Weakly Interacting Massive Particle) detector with a neutron veto system is designed to better reject neutrons. Two experimental configurations are studied in the present paper: one is for an Xe detector enclosed in a Gd-loaded scintillator and the other one is for an Xe detector placed inside a reactor neutrino detector. The Gd-doped liquid scintillator (or the neutrino detector) is used as a neutron veto device. The neutron backgrounds for the two experimental designs have been estimated using Geant4 simulations. The results show that the neutron backgrounds can decrease to O(0.1) events per year per tonne of liquid Xenon. We calculate the sensitivities to spin-independent WIMP-nucleon elastic scattering. An exposure of one tonne $\times$ year could reach a cross-section of about 6$\times$$10^{-11}$ pb.
Low background techniques for the Borexino nylon vessels  [PDF]
A. Pocar
Physics , 2005, DOI: 10.1063/1.2060466
Abstract: Borexino is an organic liquid scintillator underground detector for low energy solar neutrinos. The experiment has to satisfy extremely stringent low background requirements. The thin nylon spherical scintillator containment vessel has to meet cleanliness and low radioactivity levels second only, within the detector, to the scintillator itself. Overall, the background from the vessel in the fiducial volume of the detector must be kept at the level of one event per day or better. The requirements, design choices, results from laboratory tests, and fabrication techniques that have been adopted to meet this goal are presented. Details of the precautions taken during the installation of the vessels inside the Borexino detector are also discussed.
Removal of Heavy Metals from Liquid Laboratory Waste Using Precipitation and Adsorption Methods
Suprihatin,Nastiti Siswi Indrasti
Makara Seri Sains , 2010,
Abstract: Liquid laboratory waste (such as residue of Chemical Oxygen Demand/COD analysis) contains high concentration of heavy metals (mercury/Hg, silver/Ag and chrome/Cr) and has a high potential to pollute the environment. The liquid waste generated by laboratories is generally in small quantity, but it is extremely toxic. It is urgently in need to find out an appropriate method to reduce the problems according to the liquid waste characteristics. In this research work, precipitation and adsorption methods were evaluated to remove Hg, Ag and Cr from liquid laboratory waste, covering determination of optimum process conditions, levels of removal and achievable treated waste quality. Results showed that a Cr removal of 97% was obtained by pH 10, and Hg and Ag removals of 97-99% were reached by pH 12. Although heavy metals removals using precipitation was very significant, but the concentration of heavy metals in the treated waste was still high (0.73-2.62 mg/L) and need for further treatment. Applying activated carbon adsorption for further treatment of the effluent reduced dissolved heavy metals to 0-0.05 mg/L, depending on the type of heavy metals as well as the type and dosing of activated carbon.
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