Abstract
Several experiments on the study of the electron neutrino mass are based on high-statistics measurements of the energy spectrum following electron capture of the radionuclide 163Ho. They rely on the availability of large, radiochemically pure samples of 163Ho. Here, we describe the production, separation, characterization, and sample production within the Electron Capture in Holmium-163 (ECHo) project. 163Ho has been produced by thermal neutron activation of enriched, prepurified 162Er targets in the high flux reactor of the Institut Laue-Langevin, Grenoble, France, in irradiations lasting up to 54 days. Irradiated targets were chemically processed by means of extraction chromatography, which allowed separating the formed Ho from the 162Er target-material and from the main byproducts 170Tm and 171Tm, which are co-produced in GBq amounts. Decontamination factors of >500 for Er and of >105 for Tm and yields of 3.6·1016 and 1.2·1018 atoms of 163Ho were obtained, corresponding to a recovery yield of 95 % of Ho in the chemical separation. The Ho-fraction was characterized by means of γ-ray spectrometry, Inductively-Coupled-Plasma Mass Spectrometry (ICP-MS), Resonance Ionization Mass Spectrometry (RIMS) and Neutron Activation Analysis (NAA). In this process, the thermal neutron capture cross section of 163Ho was measured to σHo-163 to Ho-164m= (23±3) b and σHo-163 to Ho-164g= (156±9) b for the formation of the two isomers of 164Ho. Specific samples were produced for further purification by mass separation to isolate 163Ho from the Ho-isotope mixture, as needed for obtaining the energy spectrum within ECHo. The partial efficiency for this second separation step is (32±5) %.
Acknowledgements
This work was carried out in the framework of the DFG Research Unit FOR 2202 (ECHo) and we acknowledge financial support from the DFG under contracts DU 1334/1-1, EN 299/7-1, and GA 2219/2-1. H.D. acknowledges additional support by the Stufe 1 funding of the Johannes Gutenberg University Mainz. This project has received funding through the European Union’s Seventh Framework Programme for Research and Technological Development under Grant Agreements 262010 (ENSAR), 267194 (COFUND), and 289191 (LA3NET). The authors would like to thank Alexander Voegele for irradiating samples for the Ho and Er tracer at SINQ, Silvia Koechli and Anja Eichler for performing the ICP-OES measurements, Tobias Reich and Samer Amayri for performing the ICP-MS analytics as well as Ernst Schaub for technical assistance.
References
1. Gastaldo, L., Blaum, K., Chrysalidis, K., Goodacre, T. D., Domula, A., Door, M., Dorrer, H., Düllmann, Ch. E., Eberhardt, K., Eliseev, S., Enss, C., Faessler, A., Filianin, P., Fleischmann, A., Fonnesu, D., Gamer, L., Haas, R., Hassel, C., Hengstler, D., Jochum, J., Johnston, K., Kebschull, U., Kempf, S., Kieck, T., Köster, U., Lahiri, S., Maiti, M., Mantegazzini, F., Marsh, B., Neroutsos, P., Novikov, Yu.N., Ranitzsch, P. C. O., Rothe, S., Rischka, A., Saenz, A., Sander, O., Schneider, F., Scholl, S., Schüssler, R. X., Schweiger, Ch., Simkovic, F., Stora, T., Szücs, Z., Türler, A., Veinhard, M., Weber, M., Wegner, M., Wendt, K., Zuber, K.: The electron capture 163Ho experiment – ECHo. Eur. Phys. J. Spec. Top. 226, 1623 (2017).10.1140/epjst/e2017-70071-ySearch in Google Scholar
2. Gastaldo, L., Blaum, K., Doerr, A., Düllmann, Ch. E., Eberhardt, K., Eliseev, S., Enss, C., Faessler, A., Fleischmann, A., Kempf, S., Krivoruchenko, M., Lahiri, S., Maiti, M., Novikov, Yu. N., Ranitzsch, P. C.-O., Simkovic, F., Szusc, Z., Wegner, M.: The electron capture 163Ho experiment ECHo. J. Low Temp. Phys. 176, 876 (2014).10.1007/s10909-014-1187-4Search in Google Scholar
3. Hassel, C., Blaum, K., Goodacre, T. D., Dorrer, H., Düllmann, Ch. E., Eberhardt, K., Eliseev, S., Enss, C., Filianin, P., Fäßler, A., Fleischmann, A., Gastaldo, L., Goncharov, M., Hengstler, D., Jochum, J., Johnston, K., Keller, M., Kempf, S., Kieck, T., Köster, U., Krantz, M., Marsh, B., Mokry, C., Novikov, Yu. N., Ranitzsch, P. C. O., Rothe, S., Rischka, A., Runke, J., Saenz, A., Schneider, F., Scholl, S., Schüssler, R. X., Simkovic, F., Stora, T., Thörle-Pospiech, P., Türler, A., Veinhard, M., Wegner, M., Wendt, K., Zuber, K.: Recent results for the ECHo experiment. J. Low Temp. Phys. 184, 910 (2016).10.1007/s10909-016-1541-9Search in Google Scholar
4. Baisden, P. A., Sisson, D. H., Niemeyer, S., Hudson, B., Bennett, C. L., Naumann, R. A.: Measurement of the half-life of 163Ho. Phys. Rev. C 28, 337 (1983).10.1103/PhysRevC.28.337Search in Google Scholar
5. Gastaldo, L.: In: E. Kearns, G. Feldman (Eds.), XXVI Int. Conf. Neutrino Physics and Astrophysics: Neutrino 2014 (2015), AIP Publishing LLC, Boston, MA, USA, Vol. 1666, p. 050001.Search in Google Scholar
6. Faler, K. T.: Determination of the half-life of the longer-lived 166Ho isomer. J. Inorg. Nucl. Chem. 27, 25 (1965).10.1016/0022-1902(65)80185-3Search in Google Scholar
7. Engle, J. W., Birnbaum, E. R., Trellue, H. R., John, K. D., Rabin, M. W., Nortier, F. M.: Evaluation of 163Ho production options for neutrino mass measurements with microcalorimeter detectors. Nucl. Instrum. Methods B 311, 131 (2013).10.1016/j.nimb.2013.06.017Search in Google Scholar
8. Maiti, M., Lahiri, S., Szücs, Z.: Separation of 163Er from dysprosium target: a step toward neutrino mass measurement through electron capture of 163Ho. J. Radioanal. Nucl. Chem. 307, 1667 (2016).10.1007/s10967-015-4496-4Search in Google Scholar
9. Mocko, V., Taylor, W. A., Nortier, F. M., Engle, J. W., Barnhart, T. E., Nickles, R. J., Pollington, A. D., Kunde, G. J., Rabin, M. W., Birnbaum, E. R.: Isolation of 163Ho from dysprosium target material by HPLC for neutrino mass measurements. Radiochim. Acta 103, 577 (2015).10.1515/ract-2014-2362Search in Google Scholar
10. Guéguen, F., Isnard, H., Kossert, K., Bresson, C., Caussignac, C., Stadelmann, G., Nonell, A., Mialle, S., Chartier, F.: Purification of a 166mHo solution by successive high-performance liquid chromatography and gravitational chromatography for half-life determination. J. Radioanal. Nucl. Chem. 302, 289 (2014).10.1007/s10967-014-3290-zSearch in Google Scholar
11. Dadachova, E., Mirzadeh, S., Lambrecht, R. M., Hetherington, E. L., Knapp, F. F. Jr.: Separation of carrier-free holmium-166 from neutron-irradiated dysprosium targets. Anal. Chem. 66, 4272 (1994).10.1021/ac00095a024Search in Google Scholar
12. Lahiri, S., Volkers, K. J., Wierczinski, B.: Production of 166Ho through 164Dy(n,γ)165Dy(n, γ)166Dy(β−)166Ho and separation of 166Ho. Appl. Radiat. Isot. 61, 1157 (2004).10.1016/j.apradiso.2004.03.117Search in Google Scholar PubMed
13. Gastaldo, L., Ranitzsch, P. C.-O., Seggern, F. v., Porst, J.-P., Schäfer, S., Pies, C., Kempf, S., Wolf, T., Fleischmann, A., Enss, C., Herlert, A., Johnston, K.: Characterization of low temperature metallic magnetic calorimeters having gold absorbers with implanted 163Ho ions. Nucl. Instrum. Methods A 711, 150 (2013).10.1016/j.nima.2013.01.027Search in Google Scholar
14. Schneider, F., Chrysalidis, K., Dorrer, H., Düllmann, Ch. E., Eberhardt, K., Haas, R., Kieck, T., Mokry, C., Naubereit, P., Schmidt, S., Wendt, K.: Resonance ionization of holmium for ion implantation in microcalorimeters. Nucl. Instrum. Methods B 376, 388 (2016).10.1016/j.nimb.2015.12.012Search in Google Scholar
15. Schneider, F., Beyer, T., Blaum, K., Block, M., Chenmarev, S., Dorrer, H., Düllmann, Ch. E., Eberhardt, K., Eibach, M., Eliseev, S., Grund, J., Köster, U., Nagy, Sz., Novikov, Yu. N., Renisch, D., Türler, A., Wendt, K.: Preparatory studies for a high-precision Penning-trap measurement of the 163Ho electron capture Q-value. Eur. Phys. J. A 51, 89 (2015).10.1140/epja/i2015-15089-8Search in Google Scholar
16. Eliseev, S., Blaum, K., Block, M., Chenmarev, S., Dorrer, H., Düllmann, Ch. E., Enss, C., Filianin, P. E., Gastaldo, L., Goncharov, M., Köster, U., Lautenschläger, F., Novikov, Yu. N., Rischka, A., Schüssler, R. X., Schweikhard, L., Türler, A.: Direct measurement of the mass difference of 163Ho and 163Dy solves the Q-value puzzle for the neutrino mass determination. Phys. Rev. Lett. 115, 062501 (2015).10.1103/PhysRevLett.115.062501Search in Google Scholar
17. Zimmer, K.: Bestimmung von 89Sr und 90Sr mit Resonanz-Ionisations-Spektroskopie in kollinearer Geometrie, PhD Thesis, Johannes Gutenberg University Mainz (1995).Search in Google Scholar
18. Studer, D., Dyrauf, P., Naubereit, P., Heinke, R., Wendt, K.: Resonance ionization spectroscopy in dysprosium. Hyperfine Interact. 238, 8 (2017).10.1007/s10751-016-1384-4Search in Google Scholar
19. Letokov, V. S.: Laser-induced processes in spectroscopy, isotope separation, and photochemistry. Sov. Phys. Usp. 29, 70 (1986).10.1070/PU1986v029n01ABEH003085Search in Google Scholar
20. Kugler, E.: The ISOLDE facility. Hyperfine Interact. 129, 23 (2000).10.1023/A:1012603025802Search in Google Scholar
21. Mishin, V. I., Fedoseyev, V. N., Kluge, H.-J., Letokov, V. S., Ravn, H. L., Scheerer, F., Shirakabe, Y., Sundell, S., Tengblad, O. ISOLDE Collaboration: Chemically selective laser ion-source for the CERN-ISOLDE on-line mass separator facility. Nucl. Instrum. Methods B 73, 550 (1993).10.1016/0168-583X(93)95839-WSearch in Google Scholar
22. Rothe, S., Goodacre, T. D., Fedorov, D. V., Fedosseev, V. N., Marsh, B. A., Molkanov, P. L., Rossel, R. E., Seliverstov, M. D., Veinhard, M., Wendt, K. D. A.: Laser ion beam production at CERN-ISOLDE: new features – more possibilities. Nucl. Instrum. Methods B 376, 91 (2016).10.1016/j.nimb.2016.02.024Search in Google Scholar
23. Danon, Y., Werner, C. J., Youk, G., Block, R. C., Slovacek, R. E., Francis, N. C.: Neutron total cross-section measurements and resonance parameter analysis of holmium, thulium, and erbium from 0.001 to 20 keV. Nucl. Sci. Eng. 128, 61 (1998).10.13182/NSE98-A1945Search in Google Scholar
©2018 Walter de Gruyter GmbH, Berlin/Boston
