Radiolysis and radionuclide production in a flowing-water target during fast 40Ca20+ irradiation.

Production, Collection, and Purification of 47Ca for the Generation of 47Sc through Isotope Harvesting at the National Superconducting Cyclotron Laboratory

“…These predictions are significantly lower than the production rate measured in this work. This difference demonstrates the importance of measuring the production rate of radionuclides in the isotope harvesting system as predictions have been found to be inaccurate as seen previously with a 40 Ca beam experiment with a water target at the NSCL …”

“…This difference demonstrates the importance of measuring the production rate of radionuclides in the isotope harvesting system as predictions have been found to be inaccurate as seen previously with a 40 Ca beam experiment with a water target at the NSCL. 38 The measured production rate can be extrapolated to higher intensity irradiations anticipated at the NSCL and FRIB. This allows for more detailed safety and experimental planning for future isotope harvesting of 47 Ca.…”

“…37 This analysis was performed to identify and semiquantify stable ions above the limit of detection of the instrument with a one-point calibration semiquantification method for 69 elements. Among these elements were those that would indicate corrosion of the target or metal components in the system (e.g., Ti, V, Al, Fe, Ni, Cr) and elements that have been previously identified as common contaminants in the isotope harvesting system 38 (e.g., Na, Mg, Ca, Si, Zn). More details on this method and sample preparation are given in the Supporting Information.…”

“…However, upwards of 90% of the accelerated stable beam at the NSCL goes unreacted at the target, is separated from the secondary exotic product beams, and is collected in a solid metal block known as a beam blocker. By replacing the current beam blocker with a flowing-water target ( i.e ., a metal shell with a hollow interior through which water flows), the radionuclides formed from this “left-over” beam can be accessed …”

“…Several previous experiments have been performed to test the feasibility of this isotope production method at the NSCL. − These experiments range from collecting radioactive secondary beams in a water matrix to irradiating a prototype flowing-water target with a stable primary beam. This work has led to the development of a flowing-water target and extended water system for use in the beam blocker position at the NSCL (see Figure for a simplified schematic and Figure S1 in the Supporting Information for a more detailed schematic) .…”