3.3 Reactions Initiated by Uncharged Particles
37
with Beryllium increases thermal neutron density, and also decreases γ -radiation.
Although this, in fact, is the cheapest neutron source available, has the disadvantage
of short half-life (60.9 days), and high γ -flux, this means, after about 4–6 months, the
ampule containing Beryllium and Antimony is radiated in the reactor to regenerate
neutron activity. However, neutrons are slow, and require little moderating.
3.4 Particle Accelerators
Radioactive as well as stable isotopes are synthesized with the help of various types
of accelerators. Some of the accelerators which are commonly used for carrying out
high energy nuclear reaction are discussed here. For the synthesis of an isotope, first
a suitable target material is selected like Carbon-12, and this material is bombarded
by high energy nucleons (known as projectiles) like Helium atom or proton or any
other heavier particles. The energy of these projectiles is increased with the help of
accelerators that are is able to cross the nucleus barrier and enter the nucleus. Once
it has entered the nucleus, a new isotope is created.
Normally, the projectiles are charged particles. These charged particles are kept in
either a tubular or circular unit, which has the facility to create increasing potential. A
gradual increase in the potential of an opposite charge forces the projectile to move
with increasing velocity. Due to the attraction between the opposite charges, the
projectiles gain acceleration and accordingly their kinetic energy increases. When
the kinetic energy of the projectile is increased to a required value, it is allowed to
bombard (i.e., interact with) the target material to produce the desired product. For
gaining the required kinetic energy, the length of the tunnel through which projectiles
move is kept very long. During the acceleration of the projectile, charges should not
interact with the body of the long tunnel and lose their kinetic energy. To prevent the
projectile from interacting with the body of the tunnel, a magnetic field is introduced
along the tunnel. Magnetic field helps in making the projectiles move in a circular
path without interacting with the main body of the tunnel.
There are different types of accelerators like Cyclotron, Linearaccelerator, Betatron, Synchrocyclotron, which are used for this purpose. Some of
the common types are briefly discussed here:
Synchrotron is a cyclic particle accelerator. The magnetic field is time dependent
and is synchronized to the particle beam of increasing kinetic energy. This was the
first type of accelerator discovered which led to the development of various other
types of accelerators. The largest accelerator is made in 2008 with a circumference
of 27 km.
Linear accelerator (LINAC) is an instrument, which accelerates electrons by
increasing their kinetic energy through a linear tube to a very high speed. This is
used as a radiosurgery unit. The high energy X -rays generated in this system are
used to destroy tumors.
37
with Beryllium increases thermal neutron density, and also decreases γ -radiation.
Although this, in fact, is the cheapest neutron source available, has the disadvantage
of short half-life (60.9 days), and high γ -flux, this means, after about 4–6 months, the
ampule containing Beryllium and Antimony is radiated in the reactor to regenerate
neutron activity. However, neutrons are slow, and require little moderating.
3.4 Particle Accelerators
Radioactive as well as stable isotopes are synthesized with the help of various types
of accelerators. Some of the accelerators which are commonly used for carrying out
high energy nuclear reaction are discussed here. For the synthesis of an isotope, first
a suitable target material is selected like Carbon-12, and this material is bombarded
by high energy nucleons (known as projectiles) like Helium atom or proton or any
other heavier particles. The energy of these projectiles is increased with the help of
accelerators that are is able to cross the nucleus barrier and enter the nucleus. Once
it has entered the nucleus, a new isotope is created.
Normally, the projectiles are charged particles. These charged particles are kept in
either a tubular or circular unit, which has the facility to create increasing potential. A
gradual increase in the potential of an opposite charge forces the projectile to move
with increasing velocity. Due to the attraction between the opposite charges, the
projectiles gain acceleration and accordingly their kinetic energy increases. When
the kinetic energy of the projectile is increased to a required value, it is allowed to
bombard (i.e., interact with) the target material to produce the desired product. For
gaining the required kinetic energy, the length of the tunnel through which projectiles
move is kept very long. During the acceleration of the projectile, charges should not
interact with the body of the long tunnel and lose their kinetic energy. To prevent the
projectile from interacting with the body of the tunnel, a magnetic field is introduced
along the tunnel. Magnetic field helps in making the projectiles move in a circular
path without interacting with the main body of the tunnel.
There are different types of accelerators like Cyclotron, Linearaccelerator, Betatron, Synchrocyclotron, which are used for this purpose. Some of
the common types are briefly discussed here:
Synchrotron is a cyclic particle accelerator. The magnetic field is time dependent
and is synchronized to the particle beam of increasing kinetic energy. This was the
first type of accelerator discovered which led to the development of various other
types of accelerators. The largest accelerator is made in 2008 with a circumference
of 27 km.
Linear accelerator (LINAC) is an instrument, which accelerates electrons by
increasing their kinetic energy through a linear tube to a very high speed. This is
used as a radiosurgery unit. The high energy X -rays generated in this system are
used to destroy tumors.