Explain the Phenomenon of Transmutation by Deuterons.

 Transmutation by Deuterons

          The deuteron is a heavy isotope of hydrogen. It was discovered by Murphy Deuteron. The reactions induced by deuterons have great importance in nuclear physics. The product particles like proton, neutron, and alpha particles often appear in groups having different energies during these reactions. 

          The deuteron induced reactions are different then other induced nuclear reactions because charge distribution of deuteron is not symmetric and having loosely structure. The result is a compound nucleus when a nucleus _ZX^A is bombarded with deuteron. 

         (₁H²)     +          _ZX^A         ⟶           [_Z+1Cn^A+2]

In the second step, compound nucleus breaks in many ways as shown. 

          The other two processes are as

1.       The target nucleus splits into proton and neutron by the action of Coulomb force when a deuteron passes near the target nucleus.

   

           d     +       X              →      P     +      n 

           

2.       When a deuteron is incident on a target nucleus, either proton enters the nucleus first or neutron enters the first. 

          The probability of entering the neutron first is more because it faces no coulomb barrier.

          

          If neutron reaches first

                   n        +     _ZX^A       →              _ZCn^A+1         +         P 

          If proton reaches first

                 P        +     _ZX^A       →              _Z+1Cn^A+1         +       n

(d, α) Nuclear Reactions

          The deuterons are accelerated up to energies of several MeV in a cyclotron. One of the first deuteron induced reaction studied was with lithium. 

          The (d, α) nuclear reactions are generally exothermic because their Q value is positive.

                ₁H²      +     ₃Li⁶     →  [ ₄Be⁸ ]    →     ₂He⁴      +     ₂He⁴ 

          The other examples of (d, α) nuclear reactions are 

                ₁H²      +     ₈O¹⁶     →  [ ₉F¹⁸ ]    →     ₇N¹⁴      +     ₂He⁴ 

                ₁H²      +     ₁₃Al²⁷     →  [ ₁₄Si²⁹ ]    →     ₁₂Mg²⁵      +     ₂He⁴ 

          The general form of reaction is 

                ₁H²     +          _ZX^A         ⟶   [_Z+1Cn^A+2]      →     _{Z -1}Y^{A -2}      +     ₂He⁴ 

(d, P) Nuclear Reactions

          The result of (d, P) nuclear reactions is to increase the mass of the nucleus by one unit leaving the charge unchanged. The (d, P) nuclear reactions are generally exothermic because their Q value is positive. The general form of reaction is 

              ₁H²     +          _ZX^A         ⟶   [_Z+1Cn^A+2]      →     _ZY^A+1     +     ₁H¹ 

Examples

          ₁H²     +          ₁₁Na²³         ⟶   [₁₂Mg²⁵]      →     ₁₁Na²⁴    +     ₁H¹ 

         ₁H²     +          ₆C¹²         ⟶   [₇N¹⁴]      →     ₆C¹³    +     ₁H¹ 

(d, n) Nuclear Reactions

          The neutrons are often produced when deuterons are bombarded on target nucleus. The general form of reaction is

          ₁H²     +          _ZX^A         ⟶   [_Z+1Cn^A+2]      →     _Z+1Y^A+1     +     ₀n¹ 

Examples

          ₁H²     +          ₆C¹²         ⟶   [₇N¹⁴]      →     ₇N¹³    +     ₀n¹ 

          ₁H²     +          ₄Be⁹         ⟶   [₅B¹¹]      →     ₅B¹⁰    +     ₀n¹ 

(d, T) Nuclear Reactions

          The general form of reaction is 

                                 ₁H²     +          _ZX^A         ⟶   [_Z+1Cn^A+2]      →     _ZY^A-1     +     ₁H³ 

Example

                               ₁H²     +          ₃Li⁷         ⟶   [₄Be⁹]      →     ₃Li⁶     +     ₁H³ 

(d, d) Nuclear Reactions

          The most interesting cases of deuteron bombardment is that in which target contains deuterons.

          The deuterium target have been made by freezing deuterium oxide or heavy water onto a surface kept cool by liquid air. 

          The excited compound nucleus [₂He⁴] can disintegrate in two ways. In first case a proton and a new isotope of hydrogen called tritium are formed. The tritium is unstable having half-life of about 12 years. 

                    ₁H²     +          ₁H²         ⟶   [₂He⁴]      →     ₁H¹     +     ₁H³_unstable    

          In second case a neutron and a stable isotope of helium are formed.

                  ₁H²     +          ₁H²_target        ⟶   [₂He⁴]      →     ₀n¹     +     ₂He³_stable