Introduction to Nuclear Physics

What is the nucleus of the atom ?

• The nucleus contains A nucleons - Yadro tarkibida A nuklonlari mavjud : A = Z protons + N neutrons
• Nucleons are hadron particles (particles governed by the strong interaction)
• Nucleons are baryons (made of 3 quarks)-Nuklonlar adron zarralari (kuchli o'zaro ta'sir bilan boshqariladigan zarralar) Nuklonlar barionlar (3 kvarkdan iborat)
• protons (uud) are positive charged particles 2000 times heavier
• than electrons. Mpc2 = 938.272 MeV Mec2 = 0.511 MeV
• neutrons (udd) are electric neutral particles with mass
• comparable to the proton one. Mnc2 = 939.565 MeV

• neutron

• electron

• proton

• neutron

• Nucleons are fermions, as well as electrons. Nuklonlar fermionlar, shuningdek elektronlardir.

• proton

• proton

• ?

• A nucleus is characterized by its mass number A and its atomic number Z.
• It is written AZX. Yadro massa soni A va atom raqami Z bilan tavsiflanadi. Bu AZX deb yoziladi.

• The nucleus is a bound system : its mass is lower than the mass of its components.
• There is a « missing mass » connected to the binding energy by the famous Einstein formula : Yadro bog'langan tizimdir: uning massasi uning tarkibiy qismlarining massasidan kamroqdir. Mashhur Eynshteyn formulasi bilan bog'lanish energiyasi dagi massa «massa deffekti» bilan aniqlaniladi.

• Nuclear interaction-
• Yadro o'zaro ta'siri

• ?

• ?

• Nuclear interaction
• Yadro o'zaro ta'siri

• What is the nucleus of the atom ?-Atomning yadrosi nima?

• The nucleus contains A nucleons : A = Z protons + N neutrons

• ATOM

• NUCLEUS

• NUCLEON

• (10-9 m)

• (10-14 m)

• (10-15 m)

• A nucleus is almost 100000 times smaller than an atom- Yadro deyarli 100 000 marta atomdan kichikroq

• Do all the nuclei have the same radius ?
• Barcha yadrolar bir xil radiusga egami?

• features of the nucleus : the scale of a nucleus
• yadroning xususiyatlari: yadro masshtabi

• R = 1.25 x A1/3 (fm)

• The radius increases with A1/3 Radius A1/3 nisbat bilan ortadi
•  The volume increases with the number of particles Hajmi zarrachalar soni bilan ortadi

• Radii are extracted from elastic
• scattering of  particles on different targets.
• Radiuslar  zarrachalarning turli nishonlarga elastik sochilishidan olinadi.

• R(fm)

• 1fm = 10-15 m

• features of the nucleus : radius
• Yadroning xususiyatlari: radius

• Ground–state nuclear deformation predicted with the Hartree-Fock-Bogoliubov approach with the Gogny force
• Gogni kuchi bilan Xartri Fok-Bogoliubov yondashuvi orqali taxmin qilingan asosiy yadroviy deformatsiya

• Nuclei are predicted to be either: Yadrolar quyidagilardan biri bo'lishi taxmin qilinadi: spherical- sharsimon prolate-yassi or oblate-tekis

• features of the nucleus : shape Yadroning xususiyatlari: shakli

• www-phynu.cea.fr

• features of the nucleus : shape, density
• Yadroning xususiyatlari: shakli, zichligi

• 208Pb

• features of the nucleus: binding energy yadroning xususiyatlari: bog'lanish energiyasi

• A nucleus is a bound system-Yadro bog'langan tizimdir
• i.e. its mass is lower than the mass of its components.
• (if not the nucleus would release its excess of energy by spontaneously evolving to a state of lower energy composed of free particles)

• « free » nucleons ≈ A× 1000 MeV
• B(A,Z) ≈ A× 8 MeV
• nucleus : M(A,Z) ≈ A× (1000 - 8) MeV

• B(A,Z)

• ...

• Z

• ...

• N

• A=Z+N

• Mass ~ Energy ~ Instability- beqarorlik

• M(A,Z) = N Mn + Z Mp – B(A,Z)

• Stable bound system for B > 0
• Note : B is the “missing mass”
• Matomic(A,Z)=A (1amu) + Δm Δm = «mass excess -ortiqcha massa»
• Δm= 0 for 126C => 1 amu = 931,500 MeV

• ...

• ...

• Nucleus

• Distance between
• the nucleons (fm) –nuqlonlar
• orasidagi masofa

• VNN

• 1 GeV

• -50 MeV

• 1

• 2

• 3

• 

• 
• 

• 

• The nucleon-nucleon interaction is still unknown nowadays !!!
• Phenomenological parameterization of the interaction ;
• THIS IS ONE OF THE MOST IMPORTANT PROBLEM NOWADAYS
• Nuklon va nuklonlarning o'zaro ta'siri hozirgacha noma'lum !!! O'zaro ta'sirning fenomenologik parametrlanishi; BU HOZIRGI ZAMANDA ENG MUHIM MUAMMOLARDAN BIRI

• Binding energy: nucleon-nucleon potential Bog'lanish energiyasi: nuklon-nuklon potensiali

• features of the nucleus : binding energy
• Yadroning xususiyatlari: bog'lanish energiyasi

• Binding energy per nucleon:
• B(A,Z)/A ≈ 8 MeV
• Bir nuklonga bog'lanish energiyasi:
• B(A,Z)/A ≈ 8 MeV

• fission

• fusion

• features of the nucleus: stability
• yadroning xususiyatlari: barqarorlik

• ....free... ... nucleons...

• B(4He)+n
• 28.30

• ...

• ...

• Mass (MeV)

• ...

• 4He

• Q=17.60

• B(D)+B(T)
• 10.71

• ...

• 22286Rn

• 4He

• 22688Ra

• Q=4.871

• B(Rn)+B(4He)
• 1736.492

• B(Ra)
• 1731.626

• Fusion
• birlashish

• Α radioactivity
• radioaktivlik

• A/2

• A/2

• A

• QF≈200

• ≈2 × 1000

• ≈1800

• Fission
• parchalanish

• ...

• ...

• D

• T

• Separation energies parchalanish energiyasi
• For one neutron:
• S(n) =M(A-1,N-1,Z)+mn –M(A,N,Z)
• S(n)=B(A,N,Z)-B(A-1,N-1,Z)
• For one proton
• S(p) =B(A,N,Z)-B(A-1,N,Z-1)
• Two-neutron separation energy:
• S(2n)=B(A,N,Z)-B(A-2,N-2,Z)
• α particle
• S(α) = B(A,N,Z)-[B(A-4,N-2,Z-2)+B(α)]

• B(A,N,Z)

• Mass (MeV)

• A=Z+N

• n

• B(A-1,Z,N-1)+ mn

• S(n) = separation energy of one neutron in the A nucleus

• A-1

• S(n)

• features of the nucleus: separation energy
• yadroning xususiyatlari: parchalanish energiyasi

• A few nuclei are stable : their lifetimes are infinite (comparable to the
• lifetime of the proton 1033 years.) Bir nechta yadrolar barqaror: ularning umri
• cheksizdir protonning umri 1033 yil.)
• The others are unstable : they transform into more stable nuclei
• Boshqalari beqaror: ular parchalib baribir barqaror yadrolarga aylanadi

• Exponential decay-eksponensial yemirilish

• features of the nucleus: nuclear life times
• Yadroning xususiyatlari: yadroning yashash vaqtlari

• -

• +,

• 

• p

• n

• Neutrons

• Protons

• Different types of radioactivity- Radioaktivlikning har xil turlari

•  (170 h)

•  (35 h)

•  (55 y)

• (29 h)

• 22688Ra

• 22287Fr

• 22690Th

• Total versus partial life times
• To’la va qisman yashash vaqtlari

• 22689Ac

• Life times span many orders of magnitude:
• Hayot vaqtlari ko'plab kattaliklarni o'z ichiga oladi:
• Nitrogen 16 T1/2 = 7.13 s
• Oxygen 15 = 2.037 mn
• Radium 224 = 3.62 d
• Carbon 14 = 5730 y
• Molybdenum 100 = 1019 y
• Tellurium 124 = 2.2 1028 y

• Examples: half lives
• Misollar yarim yemrilish davri