Measurement of radium and thorium isotopes in environmental samples by alpha-spectrometry

The final publication is available at Springer via http://dx.doi.org/10.1007/BF02035979[EN] A new method for the determination of low-level radium and thorium isotopes in environmental samples by α-spectrometry is described. Thorium and radium isotopes were chemically separated from the same sample, by using the same tracer (229Th). Two different ways were explored for the concentration process in water samples, obtaining a chemical yield for Ra isotopes between 70–90% in both cases using KMnO4 as carrier and BaCl2 and FeCl3, respectively. The method can also be directly applied for uranium measurements, but in this case there is a limitation on the range of uranium isotopes that can be analyzed.One of us (M.J.R.A.) is grateful to Institución Valenciana de Estudios e Investigación, Spain (IVEI) for fellowshipRodríguez Álvarez, MJ.; Sánchez, F. (1995). Measurement of radium and thorium isotopes in environmental samples by alpha-spectrometry. Journal of Radioanalytical and Nuclear Chemistry. 191(1):3-13. doi:10.1007/BF02035979S3131911W.H.O. Method of Radiochemical Analysis, Univ. of Tokio, Intern. edition, 23 (1967) 117.T. OKUBO, M. SAKANOUE, Geochem. J., 9 (1975) 221.TJOE-PA LIM, N. K. DAVE, N. R. CLOUTIER, Appl. Radiat. Isot., 40 (1989) 63.G. J. HANCOCK, P. MARTIN, Appl. Radiat. Isot., 42 (1991) 63.M. KOIDE, K. W. BRULAND, Anal. Chim. Acta, 75 (1975) 1.K. J. ODELL, Proc. 4th Symp. on the Determination of Radionuclides in Environmental and Biological Materials, April 1983, Ed-Rd Press, London.L. HALLSTADIUS, Nucl. Instrum. Methods Phys. Res., 223 (1984) 266.Radionuclide Transformations, Annals of the ICRP, ICRP Publication 38, Pergamon Press, Vol. 11, 1983, p. 13.M. J. RODRÍGUEZ-ALVAREZ, F. SÁNCHEZ, E. NAVARRO, Proc. 3rd Inter. Summer School, Huelva Spain, M. GARCÍA-LEÓN and G. MADURGA (Eds), World Scientific, Singapore, 1994.M. J. RODRÍGUEZ-ALVAREZ, F. SÁNCHEZ, J. Radioanal. Nucl. Chem., 190 (1995) 123.C. W. SILL, Anal. Chem., 49 (1977) 618.J. L. GASCÓN MURILLO, PhD Thesis, University of Zaragoza, Spain, 1990.M. C. MORÓN, A. MARTINEZ-AGUIRRE, M. GARCÍA-LEÓN, Intern. Conf. on Environmental Radioactivity in the Mediterranean Area, Barcelona, 10–13 May 1988. SNE-ENS, Barcelona, 1988, p. 111.M. YAMAMOTO, K. KOMURA, K. UENO, Radiochim. Acta, 46 (1989) 137.R. GARCÍA-TENORIO, M. GARCÍA-LEÓN, G. MADURGA, C. PIAZZA, Anal. Física B, 82 (1986) 238

Narrowband searches for continuous and long-duration transient gravitational waves from known pulsars in the LIGO-Virgo third observing run

Isolated neutron stars that are asymmetric with respect to their spin axis are possible sources of detectable continuous gravitational waves. This paper presents a fully coherent search for such signals from eighteen pulsars in data from LIGO and Virgo's third observing run (O3). For known pulsars, efficient and sensitive matched-filter searches can be carried out if one assumes the gravitational radiation is phase-locked to the electromagnetic emission. In the search presented here, we relax this assumption and allow both the frequency and the time derivative of the frequency of the gravitational waves to vary in a small range around those inferred from electromagnetic observations. We find no evidence for continuous gravitational waves, and set upper limits on the strain amplitude for each target. These limits are more constraining for seven of the targets than the spin-down limit defined by ascribing all rotational energy loss to gravitational radiation. In an additional search, we look in O3 data for long-duration (hours–months) transient gravitational waves in the aftermath of pulsar glitches for six targets with a total of nine glitches. We report two marginal outliers from this search, but find no clear evidence for such emission either. The resulting duration-dependent strain upper limits do not surpass indirect energy constraints for any of these targets