The present chapter is an introduction to various scientific and technological fields. It is a beginning step to trail further study in this book. The first chapter specifies the contemporary idea and fundamental understandings of nuclear physics, which is necessary to develop the rest of the studies in this domain. The present chapter deals with an introduction to nuclei, constituents of the nucleus and its properties, mass defects and binding energy, nuclear reactions, the Q-value of nuclear reactions, and the discovery of the neutron and nuclear chain reactions. 

The present chapter deals with the analysis and relationship of significant features of theoretical nuclear physics. It is perhaps the most widely adopted chapter on the subject. The authors' line of understanding is subjected to “the theoretical perceptions, approaches, and deliberations formulated to infer the investigational matter and spread our aptitude to calculate and govern nuclear occurrences.” The present chapter elaborates on the features of conjectural nuclear physics. Its attention is classified agreeing to occurrences concerning nuclear fission, transition state (saddle point) and scission point, photo−fission, fissile materials and fertile materials, moderation and thermalization of the neutron, neutron transport in the matter, nuclear fusion and basic reaction for energy generation in the sun by fusion.

An atom's nucleus comprises neutrons and protons, which in turn are the appearance of more fundamental particles, called quarks, that are seized in a relationship by the strong nuclear force in certain stable arrangements of hadrons, called baryons. The strong nuclear force encompasses far enough from each baryon to drag the neutrons and protons together beside the repulsive electrical force between the positively charged protons. The present chapter deals with investigating and correlating key features of the nuclear structure and its properties as understanding the structure of the atomic nucleus is one of the central challenges in nuclear physics. The line of understanding in this chapter is subjected to the structure of nuclei, atomic models, Rutherford model of the atom, nuclear composition, nuclear properties, determination of mass and determination of the charge.

 Many of the particle detectors developed are gaseous based on ionization. The semiconductor and scintillation detectors are the most typical and cast-off, but other, entirely diverse ideologies have also been functional, like Cerenkov light and transition radiation. Recent detectors in particle physics pool numerous elements in layers much like an onion. The present chapter is aimed to deliberate the significant aspects of G. M. Counter (Geiger-Muller Counters), Wilson cloud chamber, Scintillation counter and a semiconductor detector.

Particle accelerators are devices that increase the speed of elementary particles like electrons or protons. Such particles are accelerated to enormously elevated energies and yield an energetic stream of beams recycled for appreciative identifications about the forces that act upon them (elemental and nuclear behaviour) and fundamental structure wedges of natural surroundings. The present chapter is dedicated to understandings of Linear accelerators along with construction working, calculation of the length of drift tubes, and calculation of particle energy. It also focuses on the cyclotron, its principle, construction, working and applications.

The present chapter is thoroughly dedicated to nuclear power reactors to understand its fundamental conceptions. It also envelops the ancient background and constructed nuclear fission reactors, important components of nuclear reactors, thermal reactors, heavy water, moderator reactors, graphite-gas moderator reactors, and accelerator-driven subcritical reactors (ADSR). The Oklo ancient nuclear reactor is the foundation of natural fission reactors.

Radioactivity, also known as nuclear decay, radioactivity, radioactive disintegration or nuclear disintegration, is the progression by which an unstable atomic nucleus drops energy by radiation. A material comprising unbalanced nuclei is considered radioactive. Three of the most common types of decay are alpha decay (α - decay), beta decay (β-decay), and gamma decay (γ-decay). The present chapter envelops the fundamental understanding of radioactivity. It progresses through the introduction to radioactivity, alpha decay, magnetic spectrometer, determination of energy of α (Alpha) particle, Gamow’s Theory of Alpha decay, beta decay, measurement of energy of beta particle and Neutrino Theory of Beta decay: (Pauli’s Neutrino Hypothesis, Fermi theory of Beta decay, Gamma Decay, Measurement of Gamma γ-Ray Energies.

A brief introduction to radioisotopes, radiation sources, types of radiation, their applications, effects and occupational protection has been presented in this chapter. The sources of radiation (whether natural or artificial) have been discussed. However, special emphasis has been given to natural radioactive decay series and artificial radioisotopes. Applications of ionizing radiations have significantly improved the quality of human life. The contribution and application of radioisotopes in various spheres of life, viz. tracing, radiography, food preservation and sterilization, eradication of insects and pests, medical diagnosis and therapy and new varieties of crops in the agricultural field, have been presented briefly. In this chapter, we have first discussed the natural origin of radioactivity and the production of radioactive elements in neutron and charged-particle streams, then exchanged the data and facts to see how high-energy particles lose energy during their interaction with matter. Finally, fossil radioactivity, artificial radioactivity, applications of radioactivity in medicinal and pharmaceutical extent, and nuclear dating followed by some wide-range applications of radioactivity have been discussed.

Physical cosmology is a branch of cosmology concerned with studying cosmological models. An astrophysical model, or merely cosmology, explains the largest-scale assemblies and dynamics of the universe and allows the study of necessary inquiries about its beginning, configuration, progress and conclusive fortune. In the present chapter, we tried to envelop the fundamental conceptions of Nuclear Cosmology and Elementary Particles encompassing primary and secondary Cosmic Rays (CR), the composition of CRs in the solar system and the Galaxy, elementary particles and their entire characteristics, matter and antimatter, generations of matter and fundamental forces with necessary schematics and illustrations.

Nuclear Astrophysics is a field at the joining of nuclear physics and astrophysics that try to find and recognize how nuclear processes shape the universe. In essence, we look in the present chapter for the connection between the properties of atomic nuclei and the properties of planets, stars, and galaxies. The present chapter encloses astrophysics of the universe, theories on the creation of the universe, formation of a star, thermonuclear reactions in stars, nucleosynthesis, a process for the production of elements, death of a star and the age of our Galaxy.