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James Van Allen journal, 1951?-December 1954

Page 90

k = (400 particles / ((m exponent 2) second sterad)) for helium

k = (20 particles / ((m exponent 2) second sterad)) for [C, N, O, ?]

k = (8 particles / ((m exponent 2) second sterad)) for (Z >= 10)

Proton spectrum (Winckler has all heavier)

N(epsilon) = (((4000)/((1 + epsilon) exponent 1.07)) particles / ((m exponent 2) second sterad)).

True exponent may be higher and numerator slightly lower.
   In any case it seems that the velocity spectrum of all particles of charge (Z > 1) is independent of the mass of the particle and that the chemical composition of that part of the beam stays constant for energies between 0.35 < epsilon ~< 10 Bev / nucleon.
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mean free path:
   For [glass?] and brass, the experimental M.F.P. are appreciably longer than geometrical  ([D?]R=0) and are given by
sigma = (pi) (((R sub 1 {target}) + (R sub 2 {projectile}) - (2(delta)R)) exponent 2)

R = (1.45 x (10 exponent -13)) (A exponent (1/3)) cm.

((delta)(R)) = ((1.0 x (10 exponent -3)) cm).

Saving...

k = (400 particles / ((m exponent 2) second sterad)) for helium k = (20 particles / ((m exponent 2) second sterad)) for [C, N, O, ?] k = (8 particles / ((m exponent 2) second sterad)) for (Z >= 10) Proton spectrum (Winckler has all heavier) N(epsilon) = (((4000)/((1 + epsilon) exponent 1.07)) particles / ((m exponent 2) second sterad)). True exponent may be higher and numerator slightly lower. In any case it seems that the velocity spectrum of all particles of charge (Z > 1) is independent of the mass of the particle and that the chemical composition of that part of the beam stays constant for energies between 0.35 < epsilon ~< 10 Bev / nucleon. ----------------------------------------------------------------------------------------- mean free path: For [glass?] and brass, the experimental M.F.P. are appreciably longer than geometrical ([D?]R=0) and are given by sigma = (pi) (((R sub 1 {target}) + (R sub 2 {projectile}) - (2(delta)R)) exponent 2) R = (1.45 x (10 exponent -13)) (A exponent (1/3)) cm. ((delta)(R)) = ((1.0 x (10 exponent -3)) cm).