Speaker
Description
While Isotope Separation OnLine (ISOL) facilities operate with cw primary beams, ISOLDE is the only ISOL facility that receives a pulsed proton beam. It is delivered by the PSBooster injector, on average 3kW with s, Hz time structure, induces peak energy deposition in the target material in the range of 500J/cm3 -per-pulse. Past experiences show that proton beam window ruptures, liquid metal splashing and corrosion pitting, early target unit failures and accelerated isotope production target material sintering are as many adverse aging effects that can ultimately reduce the overall performance of the facility. It was also shown that the pulsed beam can enhance the release of exotic isotopes and be used to deduce physico-chemical isotope release characteristics [1].
Considering the present LHC injector upgrades (LIU) at CERN, the PSBooster is expected to deliver more than 6.1013 ppp 2GeV proton beams. These beam characteristics, if delivered to ISOLDE, could lead to an important improvement of the facility performance, provided the present target unit designs including oxides, carbides, molten and refractory metals and the target stations become compatible.
In this context, we present test experiments that were undertaken at HiRadMat on a new class of ISOL targets with unidirectional porosity and compared with beam irradiation at ISOLDE [2].
We also introduce a new spallation neutron source in the form of a segmented tungsten cylinder directly embedded in the uranium fission target, operated at high temperature under pulsed beam conditions. The tested prototype showed significantly improved fission isotope yields with respect to previous designs, and provide good isotope release characteristics for alkalis [3].
We finally provide prospects for tests at HiRadMat that could help qualify the ISOLDE target designs, should the LIU beam characteristics become available.
(1) Acknowledgements :
D. Leimbach, J. Ballof, F. B. Pamies, E. Barbero, B. Crepieux, V. Samothrakis, T. Giles, S. Warren, B. Marsh, K. Chrysalidis, S. Wilkins, C. Granados, M. Mongeot, J. Karthein, D. Houngbo, L. Popescu, M. Dierckx, L. Egoriti, A. Gottberg, M. Ballan, S. Marzari, G. Neyens, K. Johnston, A. Dorsival, A.P. Bernardes, S. Sgobba, R.Luis, S. Cimino, D. Urffer, C. Tardivat
References:
[1] Catherall, R., et al. "Radioactive ion beams produced by neutron-induced fission at ISOLDE" NIM B 204 (2003): 235-239.
T. M. Mendonca, “High Power Molten Targets for Radioactive Ion Beam Production: from Particle Physics to Medical Applications”, CERN-ACC-2014-0183, doi:10.18429/JACoW-IPAC2014-WEPRO080
Ballof, J., et al. "Radioactive boron beams produced by isotope online mass separation at CERN-ISOLDE." EPJ A 55.5 (2019): 65.
[2] Czapski, M., et al. "Porous silicon carbide and aluminum oxide with unidirectional open porosity as model target materials for radioisotope beam production." NIM B 317 (2013): 385-388.
[3] Ramos J.P. et al., “design and tests for the new CERN-ISOLDE spallation source: an integrated tungsten converter surrounded by an annular UCx target operated at 2000° C”, NIM B (2019), in the press.