Versatile production method of thin targets supported by PVA

Thin self-supporting targets are indispensable in high energy-resolution studies using a magnetic spectrometer. However, nuclear targets of alkaline and alkaline-earth metal or halogen isotopes are not easily available. In order to produce thin target foils of these elements for the use in charge-exchange reactions, we take advantage of the fact that the stable isotopes of these elements have relatively small negative Q values, while 12C and 16O have large negative Q values. Therefore, even if organic compounds containing carbon and oxygen are used as supporting material, clean spectra on alkaline and alkaline-earth metal or halogen targets can be obtained up to the excitation energies of Q-value differences. A technique to produce thin foils of the chemical compounds Na2CO3, K2CO3, CaCO3 and CaCl2 was developed using polyvinylalcohol as supporting material. Foils with a total thickness of 1–2 mg/cm2 were produced and used as targets in a (3He,t) reaction study at an incident energy of 420 MeV. Owing to the small contributions of energy-loss differences of beam and reaction products in such thin targets, a very good resolution of ΔE/E=7×10−5 was achieved in combination with a high-resolution magnetic spectrometer.