Improved energy resolution of a cyclotron beam for RBS measurements

• Published in: Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms Vol. 266; no. 10; pp. 2110 - 2112
• Main Authors: Chêne, G., Garnir, H.-P., Marchal, A., Mathis, F., Strivay, D.
• Format: Journal Article Web Resource
• Language: English
• Published: Elsevier B.V 01-05-2008; Elsevier Science
• Subjects: accelerator; Alpha; Cyclotron; Elastic scattering; Physical, chemical, mathematical & earth Sciences; Physique, chimie, mathématiques & sciences de la terre; RBS; RBS; 34.50.−s; Cyclotron; 29.30.Kv; Elastic scattering; Alpha; 29.20.Hm; 82.80.Yc
• ISSN: 0168-583X; 1872-9584; 1872-9584
• DOI: 10.1016/j.nimb.2008.02.077

For RBS (Rutherford Back Scattering) analysis, the quality of the beam is of premium importance because the depth profile resolution of the method is strongly dependent on the energy resolution of the probing beam. A magnetic analyzer, consisting of two 90 left–right bending magnets forming an achromatic doublet has been adapted to the Liege 20MeV (proton) AVF (Azimuthal Varying Field) cyclotron. The energy resolution of that system has been measured by recording the resonance width of a 32S(p,p′γ)32S (3.38MeV. p+ lab. energy). We have obtained a value of ΔE=±2keV, reducing by a factor of 20 the natural dispersion of our cyclotron.
We describe our magnetic analyzer system and present the results of our RBS measurements at energies up to 14MeV α.