1) The mass difference between two isotopes is sometimes just a neutron mass. The spectrometer should separate them very well. For such an isotope combination, the difference in radius should be around 1 cm. That is z -r,=1cm. In order to achieve this, choose a magnetic field with a magnitude in Tesla (maximum magnetic field you can obtain from a conventional magnet is around 2.5 T so be far away from this value) and choose the direction also. Then determine the velocity of isotope you need. Last calculate radius r of a Pb smallest isotope.

1) The mass difference between two isotopes is sometimes just a neutron mass. The spectrometer should separate them very well. For such an isotope combination, the difference in radius should be around 1 cm. That is z -r,=1cm. In order to achieve this, choose a magnetic field with a magnitude in Tesla (maximum magnetic field you can obtain from a conventional magnet is around 2.5 T so be far away from this value) and choose the direction also. Then determine the velocity of isotope you need. Last calculate radius r of a Pb smallest isotope.