<p>Neutron production is the critical factor in judging the success of fusion in implosion and direct heating pathways for implementing inertial confinement fusion (ICF) using CD and CD₂ targets. Therefore, identifying the source of the emitted neutrons is the most important factor in determining whether nuclear fusion has been achieved efficiently or not. Thermonuclear and beam fusions of the <i>D(d</i>,<i> n)</i>^<i>3</i><i>He</i> reaction were thought to be the only neutron-producing reactions in the ICF pathway. This work, through in-depth analysis of experimental measurements and simulations using the 3D Monte Carlo code MCUNED, demonstrates that several neutron-producing interactions contribute to the overall neutron yield. The ^<i>12</i><i>C(d</i>,<i> n)</i>^<i>13</i><i>N</i>, and <i>D(</i>^<i>12</i><i>c</i>,<i> n)</i>^<i>13</i><i>N</i> stripping reactions participate in the neutron production with much higher neutron yield compared to the <i>D(d</i>,<i> n)</i>^<i>3</i><i>He</i> fusion reaction. Deuteron Break-up, photodissociation, electro-disintegration and photonuclear reactions can contribute to the total neutron production. The relative contribution of each reaction compared to the <i>D(d</i>,<i> n)</i>^<i>3</i><i>He</i> reaction was determined. Based on the above, considering the <i>D(d</i>,<i> n)</i>^<i>3</i><i>He</i> fusion reaction as the only source of neutrons will lead to incorrect results.</p>