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 r2 – r, = 1 cm. 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 Pb204 smallest isotope. In order to produce this magnetic field, determine the current and number of turns, radius and other parameters of a solenoid you need. Also show how you will position this solenoid. Now in velocity selector region, determine the magnitude and the directions of magnetic, electric fields, length and the voltage (which will create electric field) that you need to select ions with this velocity only (Eys =?, Bys ?, Vys =?, Lys =?). =
Concentrate on lead element. All isotopes are listed in the table. Isotope masses are listed in AMU (atomic mass unit) and value of AMU is given in Physical Constants section below this document together with other physical constants.
An ionizing laser is directed onto the lead block under test such that the ionized atoms (or isotopes) leaves the lead block with an initial kinetic energy of 1 eV. The direction is conically upward but sure that the cone is larger than the entrance hole to the accelerator section. The ionized isotopes are in form. That is only a single electron is missing in lead ions. The number of ionized isotopes entering into the accelerator region corresponds to a ion current.
These ions are accelerated with a constant DC voltage in the acceleration chamber which is in the form of two parallel metal plates that have a hole in both bottom and top.
Then the ions enter to velocity selector region. In this region both electric and magnetic fields are applied. Next they enter into the mass spectrometer region. In this region there is magnetic field different than the previous region. Depending of the charge of the ions, they travel in a circular path with a well-defined radius either to the left or to the right.
Physical Constants:
1 AMU=1.66×10^(-27) kg
m_neutron=1.67×10^(-27) kg
Q_e=1.60×10^(-19) Coulombs
1 eV=1.60×10^(-19) joules
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