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Thick-Target Bremsstrahlung and Target Considerations for Secondary-Particle Production by Electrons
Phys. Rev. 149, 1248 – Published 30 September, 1966
DOI: https://doi.org/10.1103/PhysRev.149.1248
Abstract
Bremsstrahlung spectra as a function of target thickness up to several radiation lengths, to be used for particle production in high-energy electron machines, are investigated. The shower equations are cast in integral forms which are then solved by iteration. The iterations are performed up to the second-generation photons; and the numerical results show that for most experiments the first-generation photons alone will give sufficiently accurate results. For example, for a target thickness of two radiation lengths and for , where is the photon energy and is the incident electron energy, the ratio of the second- to the first-generation photon intensity is 8%. This ratio decreases rapidly as one increases and decreases the target thickness. A very simple formula which approximates the first-generation photon spectra as a function of target thickness is derived. This approximate formula is shown to be accurate enough for estimating the secondary-beam production by electrons. As by-products of our investigation the first- and the second-generation electron and positron spectra were obtained as functions of target thickness. These spectra are useful in estimating the electron and positron background. Some aspects of target considerations for the secondary-beam production are given as an illustration of the use of our formulas.
References (11)
- B. Rossi, High Energy Particles (Prentice-Hall, Inc., Engle-wood Cliffs, New Jersey, 1956)
- R. A. Alvarez, High Energy Physics laboratory, Stanford University, Internal Reports HEPL-228 and 229, 1961 (unpublished)
- H. J. Bhabha and W. Heitler, Proc. Roy. Soc. (London) A159, 432 (1937)
- H. A. Bethe and J. Ashkin, in Experimental Nuclear Physics, edited by E. Segre (John Wiley & Sons, Inc., New York, 1953)
- W. Heitler, Quantum Theory of Radiation (Oxford University Press, Oxford, England, 1954)
- L. Eyges, Phys. Rev. 76, 264 (1949)
- H. A. Bethe and W. Heitler, Proc. Roy. Soc. (London) A146, 83 (1934)
- Z. Guiragossian (private communication)
- T. Kycia et al., quoted by Lindenbaum in the Proceedings of the Twelfth Annual International Conference on High Energy Physics, Dubna, 1964 (Atomizdat, Moscow, 1965)
- T. Kycia et al.LindenbaumSLAC User's Handbook (Stanford University, Stanford, California, 1966)
- H. W. Koch and J. W. Motz, Rev. Mod. Phys. 31, 920 (1959)