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(226)Ra, (210)Pb, (210)Bi and (210)Po deposition and removal from surfaces and liquids.

Wójcik M, Zuzel G - J Radioanal Nucl Chem (2012)

Bottom Line: After several tests had been performed for both methods it was found that after the water extraction the initial lead content in the scintillator sample was reduced only accordingly to the ratio of the volumes of the applied liquids (simple dilution).In contrast to this, distillation was very effective providing in the best case a (210)Pb reduction factor higher than 100.An evidence of a reverse process was also observed-the isotopes were transferred from the etchant to the clean germanium surface.

View Article: PubMed Central - PubMed

Affiliation: M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow, Poland.

ABSTRACT

Deposition of (226)Ra from water on nylon was investigated. Measurements performed for different pH and different radium concentrations in the water gave similar absolute activities deposited on the foil surface. Obtained results were used to estimate the amount of (226)Ra plated-out on the nylon scintillator vessel in the solar neutrino experiment BOREXINO during filling of the detector. Another problem studied in the frame of BOREXINO was the removal of (210)Pb from its organic liquid scintillator by applying distillation and water extraction. After several tests had been performed for both methods it was found that after the water extraction the initial lead content in the scintillator sample was reduced only accordingly to the ratio of the volumes of the applied liquids (simple dilution). In contrast to this, distillation was very effective providing in the best case a (210)Pb reduction factor higher than 100. Removal efficiencies of the long-lived (222)Rn daughters during etching from surfaces of standard and high purity germanium were investigated in the frame of the GERDA experiment, which aims to search for neutrino-less double beta decay of (76)Ge. The standard etching procedure of Canberra used during production of high purity n-type germanium diodes was applied to germanium discs, which had been exposed earlier to a strong (222)Rn source for its progenies deposition. In contrast to copper and stainless steel, (210)Pb, (210)Bi and (210)Po was removed from germanium very efficiently. An evidence of a reverse process was also observed-the isotopes were transferred from the etchant to the clean germanium surface.

No MeSH data available.


Related in: MedlinePlus

Schematic view of the apparatus used to investigate deposition of 226Ra on the nylon foil to be used in BOREXINO
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Fig2: Schematic view of the apparatus used to investigate deposition of 226Ra on the nylon foil to be used in BOREXINO

Mentions: For the 226Ra deposition tests an emanation chamber with a volume of 20 l was used [4]. A nylon bag was formed out of a foil (Capron) considered to be used in BOREXINO and placed inside the chamber as shown in Fig. 2. It was next filled with ultra-pure water, to which in the following step known activity of 226Ra (coming from a certified solution) was added. After some time when the radium could be deposited on the foil surface (between 3 weeks and 4 months for different tests) the water was pumped out from the bag through a special pipe going to its deepest point. After each step of the above procedure the total 226Ra activity inside the chamber was precisely measured through 222Rn.1 Radon was extracted from the vessel using pure He as a carrier gas, collected in a charcoal trap and filled into a proportional counter for registration of its alpha decays [1]. Determination of the 226Ra activity in each configuration allowed to precisely determine how much 226Ra was present in the water, and how much was adsorbed on the foil. Appropriate corrections for amounts of water removed during radon extractions (sparging with He) and left over on the foil after water removal were applied. Three series of measurements were performed for different pH values of the water: 2.8, 5.7, 6.8. Respectively, different concentrations of 226Ra were applied: 1.1, 2.5, 0.5 mBq/l, as well as different exposure times (3 months, 3 weeks and 4 months, respectively). The surface area of the used foils was always about 0.2 m2 and the fraction being in direct contact with the 226Ra-rich water equaled to 0.15 m2. All relevant values and obtained activities for all three runs are collected in Tables 1 and 2.Fig. 2


(226)Ra, (210)Pb, (210)Bi and (210)Po deposition and removal from surfaces and liquids.

Wójcik M, Zuzel G - J Radioanal Nucl Chem (2012)

Schematic view of the apparatus used to investigate deposition of 226Ra on the nylon foil to be used in BOREXINO
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4514467&req=5

Fig2: Schematic view of the apparatus used to investigate deposition of 226Ra on the nylon foil to be used in BOREXINO
Mentions: For the 226Ra deposition tests an emanation chamber with a volume of 20 l was used [4]. A nylon bag was formed out of a foil (Capron) considered to be used in BOREXINO and placed inside the chamber as shown in Fig. 2. It was next filled with ultra-pure water, to which in the following step known activity of 226Ra (coming from a certified solution) was added. After some time when the radium could be deposited on the foil surface (between 3 weeks and 4 months for different tests) the water was pumped out from the bag through a special pipe going to its deepest point. After each step of the above procedure the total 226Ra activity inside the chamber was precisely measured through 222Rn.1 Radon was extracted from the vessel using pure He as a carrier gas, collected in a charcoal trap and filled into a proportional counter for registration of its alpha decays [1]. Determination of the 226Ra activity in each configuration allowed to precisely determine how much 226Ra was present in the water, and how much was adsorbed on the foil. Appropriate corrections for amounts of water removed during radon extractions (sparging with He) and left over on the foil after water removal were applied. Three series of measurements were performed for different pH values of the water: 2.8, 5.7, 6.8. Respectively, different concentrations of 226Ra were applied: 1.1, 2.5, 0.5 mBq/l, as well as different exposure times (3 months, 3 weeks and 4 months, respectively). The surface area of the used foils was always about 0.2 m2 and the fraction being in direct contact with the 226Ra-rich water equaled to 0.15 m2. All relevant values and obtained activities for all three runs are collected in Tables 1 and 2.Fig. 2

Bottom Line: After several tests had been performed for both methods it was found that after the water extraction the initial lead content in the scintillator sample was reduced only accordingly to the ratio of the volumes of the applied liquids (simple dilution).In contrast to this, distillation was very effective providing in the best case a (210)Pb reduction factor higher than 100.An evidence of a reverse process was also observed-the isotopes were transferred from the etchant to the clean germanium surface.

View Article: PubMed Central - PubMed

Affiliation: M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Cracow, Poland.

ABSTRACT

Deposition of (226)Ra from water on nylon was investigated. Measurements performed for different pH and different radium concentrations in the water gave similar absolute activities deposited on the foil surface. Obtained results were used to estimate the amount of (226)Ra plated-out on the nylon scintillator vessel in the solar neutrino experiment BOREXINO during filling of the detector. Another problem studied in the frame of BOREXINO was the removal of (210)Pb from its organic liquid scintillator by applying distillation and water extraction. After several tests had been performed for both methods it was found that after the water extraction the initial lead content in the scintillator sample was reduced only accordingly to the ratio of the volumes of the applied liquids (simple dilution). In contrast to this, distillation was very effective providing in the best case a (210)Pb reduction factor higher than 100. Removal efficiencies of the long-lived (222)Rn daughters during etching from surfaces of standard and high purity germanium were investigated in the frame of the GERDA experiment, which aims to search for neutrino-less double beta decay of (76)Ge. The standard etching procedure of Canberra used during production of high purity n-type germanium diodes was applied to germanium discs, which had been exposed earlier to a strong (222)Rn source for its progenies deposition. In contrast to copper and stainless steel, (210)Pb, (210)Bi and (210)Po was removed from germanium very efficiently. An evidence of a reverse process was also observed-the isotopes were transferred from the etchant to the clean germanium surface.

No MeSH data available.


Related in: MedlinePlus