Preparation of 26Al, 59Ni, 44Ti, 53Mn and 60Fe from a proton irradiated copper beam dump

The station for pions cancer therapy was operated at PSI from 1980 to 1992. After a cooling time of 12years it's made of copper beam dump was cut and samples were taken for analytical purposes. The sampling collected about 500g of high active copper chips that can be used for separation of exotic radionuclides. The analyses by gamma spectrometry, LSC and AMS showed main nuclides present to be 60Co, 54Mn, 22Na, 65Zn, 26Al, 53Mn, 59Ni, 63Ni, 55Fe and 60Fe and 44Ti with a daughter nuclide 44Sc. In the frame of ERAWAST project a procedure combining selective precipitation and ion exchange for the separation of the rare radionuclides from the copper beam dump was developed. The proposed separation procedure is easy for remote controlled implementation in a hot cell. The ion exchange separation of Ni, Al, Mg, Ti and Fe was complete and high decontamination factors for copper and cobalt were achieved. Based on the developed procedure a remotely controlled system for separation of exotic radionuclides from the copper chips was set up. The full scale system was installed in a hot cell where high activity levels can be handled. In order to evaluate the reliability and functionality of the system extensive tests have been done. During the test period 13.86g in total of the proton irradiated copper beam dump were processed for separation of 26Al, 59Ni, 53Mn, 44Ti and 60Fe. The results showed that the system was operational and the radionuclide separation was selective with high chemical yield. The procedure manages as well the generated liquid wastes containing high level of 60Co activit

Quantification of 60Fe atoms by MC-ICP-MS for the redetermination of the half-life

In many scientific fields, the half-life of radionuclides plays an important role. The accurate knowledge of this parameter has direct impact on, e.g., age determination of archeological artifacts and of the elemental synthesis in the universe. In order to derive the half-life of a long-lived radionuclide, the activity and the absolute number of atoms have to be analyzed. Whereas conventional radiation measurement methods are typically applied for activity determinations, the latter can be determined with high accuracy by mass spectrometric techniques. Over the past years, the half-lives of several radionuclides have been specified by means of multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) complementary to the earlier reported values mainly derived by accelerator mass spectrometry. The present paper discusses all critical aspects (amount of material, radiochemical sample preparation, interference correction, isotope dilution mass spectrometry, calculation of measurement uncertainty) for a precise analysis of the number of atoms by MC-ICP-MS exemplified for the recently published half-life determination of $^{60}$ Fe (Rugel et al, Phys Rev Lett 103:072502, 2009

Optimizing a radiochemical separation of 26Al from an acidic V-rich matrix

Sorption and desorption of Al(III) on a series of different extraction resins (LN, LN2, LN3, TK100, TK101, TK201) in acidic HNO3 media containing high concentrations of V(IV,V) was investigated. Static batch studies were conducted as a way of obtaining preliminary distribution coefficient (Kd) values that were further used to develop dynamic tests on real samples. It was shown that a complete separation and recovery of Al(III) from V(V) under acidic conditions (pH = 2) is possible by utilizing LN resin. Active “hot” dynamic studies with 26Al (≈10 Bq) as a radiotracer and real waste samples were conducted to further investigate and confirm the results of the inactive “cold” experiments. Utilizing this separation procedure, we have successfully removed all traces of 26Al (∼10−9 g) radiotracer from the bulk vanadium matrix

Development of an extraction system for the separation of dubnium from rutherfordium using MIBK and HCl/HF solutions

A chemical separation system was developed to separate group 4 and 5 elements using extraction from HCl/HF solution into methyl-isobutyl-ketone (MIBK). The system is proposed to be applied for a confident assignment of the spontaneous fissioning radionuclide produced as decay product of element 115 either as dubnium (Db, Z = 105) or rutherfordium (Rf, Z = 104). Moreover, extraction systems are proposed allowing the investigation of chemical properties of Db in comparison to the properties of its lighter homologs Nb and Ta

Radiochemical analysis of concrete samples from accelerator waste

For the decommissioning and disposal of shielding concrete from accelerator facilities, the Swiss Authorities require information on the radionuclide inventory. Besides the easy-to-measure γ-emitters 152Eu, 60Co, 44Sc, 133Ba, 154Eu, 134Cs, 144Ce, 22Na, also long-lived radionuclides emitting α- or β-radiation like 129I, 10Be, 36Cl, 239/240Pu and 238U have to be studied in order to obtain an overview to which extent they are produced and whether they represent a safety issue. In this study, we present the chemical separation and determination of selected radionuclides in shielding concrete from two different positions in the accelerator facilities at the Paul Scherrer Institute (PSI), the BX2 station, which was shut down in 1998, and the environment of the target M station, where the samples were taken in 1985 during reconstruction. The results of the measurements show that in no case the radionuclide content represents a safety risk. The components can be decommissioned corresponding to the Swiss safety regulation

Nucleotide Sequence Variation within the PI3K p85 Alpha Gene Associates with Alcohol Risk Drinking Behaviour in Adolescents

While the phosphatidylinositol 3-kinase (PI3K)-dependent signaling pathway is typically known to regulate cell growth and survival, emerging evidence suggest a role for this pathway in regulating the behavioural responses to addictive drugs.To investigate whether PI3K contributes to patterns of risky alcohol drinking in human, we investigated genetic variations in PIK3R1, encoding the 85 kD regulatory subunit of PIK, in 145 family trios consisting of 15-16 year old adolescents and their parents. Screening for mutations in exons, exon-intron boundaries and regulatory sequences, we identified 14 single nucleotide polymorphisms (SNPs) in the PIK3R1 gene region from exon 1 to the beginning of the 3' untranslated region (UTR). These SNPs defined haplotypes for the respective PIK3R1 region. Four haplotype tagging (ht)SNPs (rs706713, rs2302975, rs171649 and rs1043526), discriminating all haplotypes with a frequency >or=4.5% were identified. These htSNPs were used to genotype adolescents from the "Mannheim Study of Risk Children" (MARC). Transmission disequilibrium tests in these adolescents and their parents demonstrated sex-specific association of two SNPs, rs2302975 and rs1043526, with patterns of risky alcohol consumption in male adolescents, including lifetime prevalence of drunkenness (p = 0.0019 and 0.0379, respectively) and elevated maximum amount of drinking (p = 0.0020 and 0.0494, respectively), as a measure for binge drinking pattern.Our findings highlight a previously unknown relevance of PIK3R1 genotypes for alcohol use disorders and might help discriminate individuals at risk for alcoholism

The resonance triplet at E_alpha = 4.5 MeV in the 40Ca(alpha,gamma)44Ti reaction

The 40Ca(alpha,gamma)44Ti reaction is believed to be the main production channel for the radioactive nuclide 44Ti in core-collapse supernovae. Radiation from decaying 44Ti has been observed so far for two supernova remnants, and a precise knowledge of the 44Ti production rate may help improve supernova models. The 40Ca(alpha,gamma)44Ti astrophysical reaction rate is determined by a number of narrow resonances. Here, the resonance triplet at E_alpha = 4497, 4510, and 4523 keV is studied both by activation, using an underground laboratory for the gamma counting, and by in-beam gamma spectrometry. The target properties are determined by elastic recoil detection analysis and by nuclear reactions. The strengths of the three resonances are determined to omega gamma = (0.92+-0.20), (6.2+-0.5), and (1.32+-0.24) eV, respectively, a factor of two more precise than before. The strengths of this resonance triplet may be used in future works as a point of reference. In addition, the present new data directly affect the astrophysical reaction rate at relatively high temperatures, above 3.5 GK.Comment: 12 pages, 11 figures; submitted to Phys. Rev.

Radiochemical determination of 129I and 36Cl inMEGAPIE, a proton irradiated lead-bismuth eutectic spallation target

The concentrations of the long-lived nuclear reaction products 129I and 36Cl have been measured in samples from the MEGAPIE liquid metal spallation target. Samples from the bulk target material (lead-bismuth eutectic, LBE), from the interface of the metal free surface with the cover gas, from LBE/steel interfaces and from noble metal absorber foils installed in the cover gas system were analysed using Accelerator Mass Spectrometry at the Laboratory of Ion beam Physics at ETH Zürich. The major part of 129I and 36Cl was found accumulated on the interfaces, particularly at the interface of LBE and the steel walls of the target container, while bulk LBE samples contain only a minor fraction of these nuclides. Both nuclides were also detected on the absorber foils to a certain extent (≪ 1% of the total amount). The latter number is negligible concerning the radio-hazard of the irradiated target material; however it indicates a certain affinity of the absorber foils for halogens, thus proving the principle of using noble metal foils for catching these volatile radionuclides. The total amounts of 129I and 36Cl in the target were estimated from the analytical data by averaging within the different groups of samples and summing up these averages over the total target. This estimation could account for about half of the amount of 129I and 36Cl predicted to be produced using nuclear physics modelling codes for both nuclides. The significance of the results and the associated uncertainties are discussed