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{
"metadata": {
"name": "",
"signature": "sha256:93b6ee47cf464df569e4895dab3158be49c4f81380cffe2b4a954430fff24e01"
},
"nbformat": 3,
"nbformat_minor": 0,
"worksheets": [
{
"cells": [
{
"cell_type": "heading",
"level": 1,
"metadata": {},
"source": [
"Chapter 2: Nuclear Models"
]
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.2.1, Page 66"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable declaration\n",
"# For Ca(20,40), actual binding energy is ...... \n",
"m_p = 1.007825; # Mass of proton, amu\n",
"m_n = 1.008665; # Mass of neutron, amu\n",
"Z = 20; # Number of protons\n",
"N = 20; # Number of neutrons\n",
"M_n = 39.962591; # Mass of the nucleus, amu\n",
"B_actual = (M_n-Z*m_p-N*m_n)*931.49; # Actual binding energy, MeV\n",
"# For Ca(20,40), Binding energ as per semiemperical mas formula......\n",
"Z = 20; # Number of protons\n",
"a_v = 15.5; # Volume constant, MeV\n",
"a_s = 16.8; # Surface constant, MeV\n",
"a_a = 23.0; # Asymmetric constant, MeV\n",
"a_c = 0.7; # Coulomb constant, MeV\n",
"a_p = 34.0; # Paring constant, MeV\n",
"A = 40; # Mass number\n",
"\n",
"#Calculations\n",
"B_semi = (a_v*A-(a_s*A**(2./3))-(a_c*Z*(Z-1)/A**(1./3))-(a_a*(A-2*Z)**2/A)-(a_p*A**(-3./4))); # Binding energy as per semiemperical mass formula\n",
"# Percentage discrepancy between actual and semiemperical mass formula values are.......\n",
"Per_des = -(B_semi+B_actual)/B_actual*100; # Percentage discrepancy \n",
"\n",
"#Result\n",
"print \"Actual binding energy = %6.2f MeV\\nBinding energy as per semiemperical mass formula = %6.2f MeV\\nPercentage discrepancy = %.2f percent\"%(B_actual, B_semi, Per_des)\n",
"\n",
"#answers vary due to rounding-off errors"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Actual binding energy = -342.05 MeV\n",
"Binding energy as per semiemperical mass formula = 343.59 MeV\n",
"Percentage discrepancy = 0.45 percent\n"
]
}
],
"prompt_number": 1
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.2.2, Page 67"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable declaration \n",
" # Calculation of coulomb energy for mirror nuclei : N-7 and O-8\n",
" # For N-7 nucleus\n",
"a_c = 0.7; # Coulomb energy constant, MeV\n",
"Z_N = 7; # Atpmic no. \n",
"A = 15; # Atomic mass\n",
"E_C_N = a_c*Z_N*(Z_N-1)/(A**(1./3)); # Coulomb energy for N-7, MeV\n",
"# For O-8 nucleus\n",
"a_c = 0.7; # Coulomb energy constant, MeV\n",
"Z_O = 8; # Atpmic no. \n",
"A = 15.; # Atomic mass\n",
"\n",
"#Calculations\n",
"E_C_O = a_c*Z_O*(Z_O-1)/(A**(1./3)); # Coulomb energy for O-8, MeV\n",
"C_E_d = E_C_O-E_C_N; # Coulomb energy difference, MeV\n",
"m_p = 1.007276*931.49; # Mass of proton, MeV\n",
"m_n = 1.008665*931.49; # Mass of neutron, MeV\n",
"M_d = m_n-m_p; # Mass difference of nucleons, MeV \n",
"D_C_M = round(C_E_d-M_d); # Difference in coulomb energy and nucleon mass difference, MeV\n",
"M_O = 15.003070*931.49; # Mass of O-8, MeV\n",
"M_N = 15.000108*931.49; # Mass of N-7, MeV\n",
"D_A = (M_O-M_N); # Actual mass difference, MeV\n",
"\n",
"#Result\n",
"print \"Difference in Coulomb energy = %5.3f MeV\\nNucleon mass difference = %6.4f MeV\\nDifference in Coulomb energy and nucleon mass difference = %5.3f MeV\\nActual mass difference = %.3f MeV\"%(C_E_d, M_d ,D_C_M, D_A)\n",
"if D_A == D_C_M:\n",
" print \"Result is verified\"\n",
"\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Difference in Coulomb energy = 3.974 MeV\n",
"Nucleon mass difference = 1.2938 MeV\n",
"Difference in Coulomb energy and nucleon mass difference = 3.000 MeV\n",
"Actual mass difference = 2.759 MeV\n"
]
}
],
"prompt_number": 2
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.2.3, Page 68"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable declaration&Calculations\n",
"# For Kr-80, \n",
"m_p = 1.007825; # Mass of proton, amu\n",
"m_n = 1.008665; # Mass of neutron, amu\n",
"Z = 36; # Number of protons\n",
"N_80 = 44; # Number of neutrons\n",
"M_n_80 = 79.91628; # Mass of Kr nucleus\n",
"BE_Kr_80 = (Z*m_p+N_80*m_n-M_n_80)*931.49; # Binding energy for Kr-80, MeV\n",
"# For Kr-81,\n",
"N_81 = 45; # Number of neutrons\n",
"M_n_81 = 80.91661; # Mass of Kr-81 nucleus\n",
"BE_Kr_81 = (Z*m_p+N_81*m_n-M_n_81)*931.49; # Binding energy for Kr-81 nucleus\n",
"# For Kr-82\n",
"N_82 = 46; # Number of neutrons\n",
"M_n_82 = 81.913482; # Mass of Kr nucleus\n",
"BE_Kr_82 = (Z*m_p+N_82*m_n-M_n_82)*931.49; # Binding energy for Kr-82,MeV\n",
"# For Kr-83 \n",
"N_83 = 47; # Number of protons\n",
"M_n_83 = 82.914134; # Mass of Kr-83 nucleus\n",
"BE_Kr_83 = (Z*m_p+N_83*m_n-M_n_83)*931.49; # Binding energy for Kr-83, MeV\n",
"E_sep_81 = BE_Kr_81-BE_Kr_80; # Energy seperation of neutron for Kr-81, MeV\n",
"E_sep_82 = BE_Kr_82-BE_Kr_81; # Energy seperation of neutron for Kr-82, MeV\n",
"E_sep_83 = BE_Kr_83-BE_Kr_82; # Energy seperation of neutron for Kr-83, MeV\n",
"\n",
"#Result\n",
"print \"Energy seperation of neutron for Kr-81 = %4.2f MeV\\nEnergy seperation of neutron for Kr-82 = %4.2f MeV\\nEnergy seperation of neutron for Kr-83 = %5.2f MeV\"%(E_sep_81, E_sep_82, E_sep_83)\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Energy seperation of neutron for Kr-81 = 7.76 MeV\n",
"Energy seperation of neutron for Kr-82 = 10.99 MeV\n",
"Energy seperation of neutron for Kr-83 = 7.46 MeV\n"
]
}
],
"prompt_number": 3
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.2.4, Page 68"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import sympy\n",
"from sympy.solvers import solve\n",
"from sympy import Symbol\n",
"\n",
"#Variable declaration\n",
"a_v = 15.5; # Volume energy coefficient, MeV\n",
"a_s = 16.8; # Surface energy coefficient MeV\n",
"a_c = 0.7; # Coulomb energy coefficient, MeV\n",
"a_a = 23.0; # Asymmetric energy coefficient, MeV\n",
"a_p = 34.0; # Pairing energy coefficient, MeV\n",
"A = 75; # Given atomic mass \n",
"\n",
"#Calculations\n",
"z = Symbol('z')\n",
"B =solve((((-a_c*(2*z-1))/A**1./3)+((4*a_a*(A-2*z))/A)),z) # Binding energy as per liquid drop model\n",
"\n",
"#Result\n",
"print \"Most stable isotope of A = 75 corresponds to Z = %.d\"%B[0]\n",
"\n",
"#answer varies due to usage of sympy module"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Most stable isotope of A = 75 corresponds to Z = 37\n"
]
}
],
"prompt_number": 4
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.2.5, Page 69"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import sympy\n",
"from sympy.solvers import solve\n",
"from sympy import Symbol\n",
"\n",
"#Variable declaration\n",
"a_v = 15.5; # Volume energy, MeV \n",
"a_s = 16.8; # Surface energy, MeV \n",
"a_c = 0.7; # Coulomb energy, MeV\n",
"a_a = 23.0; # Asymmetric energy, MeV\n",
"a_p = 34.0; # Pairing energy, MeV\n",
"\n",
"z = Symbol('z')\n",
"A = 27\n",
"#Calculations\n",
"# For A = 27;\n",
"A = 27\n",
"Z_27 = ((4*a_a)+(a_c/A**1./3))/(((2*a_c)/A**1./3)+(8*a_a/A))\n",
"\n",
"# For A = 118 \n",
"A = 118\n",
"Z_118 = ((4*a_a)+(a_c/A**1./3))/(((2*a_c)/A**1./3)+(8*a_a/A))\n",
"\n",
"# For A = 238\n",
"A = 238\n",
"Z_238 = ((4*a_a)+(a_c/A**1./3))/(((2*a_c)/A**1./3)+(8*a_a/A))\n",
"\n",
"#Result\n",
"print \"Most stable isotopes for A = 27, A = 118, A = 238 corresponds to z = %d, %d and %d respectively\"%(Z_27, Z_118, Z_238)\n",
"\n",
"#Incorrect answers in the textbook"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Most stable isotopes for A = 27, A = 118, A = 238 corresponds to z = 13, 58 and 118 respectively\n"
]
}
],
"prompt_number": 5
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.2.6, Page 69"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable declaration\n",
"# Mirror nuclei : Na-11 and Mg-12 \n",
"m_p = 1.007276; # Mass of proton, amu\n",
"m_n = 1.008665; # Mass of neutron, amu\n",
"M_Mg = 22.994124; # Atomic mass of Mg-12, amu\n",
"M_Na = 22.989768; # Atomic mass of Na-11, amu\n",
"A = 23; # Mass number\n",
"Z_Mg = 12; # Atomic number of Mg-12\n",
"e = 1.6e-019; # Charge of the electron, C\n",
"K = 8.98e+09; # Coulomb force constant\n",
"\n",
"#Calculations\n",
"a_c = A**(1./3)/(2*Z_Mg-1)*((M_Mg-M_Na)+(m_n-m_p))*931.47; # Coulomb coefficient, MeV \n",
"r_0 = 3./5*K*e**2/(a_c*1.6e-013); # Nuclear radius, m\n",
"\n",
"#Result\n",
"print \"Coulomb coefficient = %4.2f MeV\\nNuclear radius = %3.1e m\"%(a_c, r_0)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Coulomb coefficient = 0.66 MeV\n",
"Nuclear radius = 1.3e-15 m\n"
]
}
],
"prompt_number": 6
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.2.7, Page 71"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"#Variable declaration\n",
"Z = 92; # Atomic number of U-236\n",
"e = 1.6e-019; # Charge of an electron, C\n",
"A = 236; # Mass number of U-236\n",
"K = 8.98e+09; # Coulomb constant,\n",
"r_o = 1.2e-015; # Distance of closest approach, m\n",
"a_s = -16.8; # Surface constant\n",
"\n",
"#Calculations\n",
"E_c = -(3*K*Z*(Z-1)*e**2)/(5*r_o*A**(1./3)*1.6e-013); # Coulomb energy, MeV\n",
"E_s = a_s*A**(2./3); # Surface energy, MeV \n",
"\n",
"#Result\n",
"print \"Coulomb energy for U(92,236) = %5.1f MeV \\nSurface energy for U(92,236) = %5.1f MeV \"%(E_c, E_s)"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"Coulomb energy for U(92,236) = -973.3 MeV \n",
"Surface energy for U(92,236) = -641.6 MeV \n"
]
}
],
"prompt_number": 8
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.3.1, Page 126"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#Variable declaration\n",
"t_prime = 1600; # Half life of radioactive material, years\n",
"t = 2000; # Total time, years\n",
"lamda = 0.6931/t_prime; # Decay constant, years^(-1)\n",
"m0 = 1; # The mass of radioactive substance at t0, mg\n",
"\n",
"#Calculations\n",
"m = m0* math.exp(-(lamda*t)); # Ratio of total number of atoms and number of atoms disintegrat, mg\n",
"a = 1-m; # The amount of radioactive substance decayed, mg \n",
"\n",
"#Result\n",
"print \"The amount of radioactive substance decayed : %6.4f mg\"%a\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The amount of radioactive substance decayed : 0.5795 mg\n"
]
}
],
"prompt_number": 9
},
{
"cell_type": "heading",
"level": 2,
"metadata": {},
"source": [
"Example 2.3.4, Page 126"
]
},
{
"cell_type": "code",
"collapsed": false,
"input": [
"import math\n",
"#Variable declaration\n",
"t_prime = 1600; # Half life of radioactive material, years\n",
"t = 2000; # Total time, years\n",
"lamda = 0.6931/t_prime; # Decay constant, years^(-1)\n",
"m0 = 1; # The mass of radioactive substance at t0, mg\n",
"\n",
"#Calculations\n",
"m = m0* math.exp(-(lamda*t)); # Ratio of total number of atoms and number of atoms disintegrat, mg\n",
"a = 1-m; # The amount of radioactive substance decayed, mg \n",
"\n",
"#Result\n",
"print \"The amount of radioactive substance decayed : %6.4f mg\"%a\n"
],
"language": "python",
"metadata": {},
"outputs": [
{
"output_type": "stream",
"stream": "stdout",
"text": [
"The amount of radioactive substance decayed : 0.5795 mg\n"
]
}
],
"prompt_number": 10
}
],
"metadata": {}
}
]
}
|