Aspects of the historical development of targetry for heavy ions of 0.05–2000 A·MeV at GSI

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• 作者：Folger ; Helmut
• 关键词：GSI ; Heavy-ion targets ; Target thickness 2× ; 10^&minus ; 6&ndash ; 20g/cm² ; Target material ; Target preparation ; Target characterization ; Target application ; SHIP target wheels ; FRS 75-target assembly
• 刊名：Nuclear Instruments and Methods in Physics Research Section A ; Accelerators ; Spectrometers ; Detectors and Associated Equipment
• 出版年：1999
• 期刊代码：41_01689002
• 类别：ph
• 出版时间：December 1, 1999
• 卷：438
• 期：1
• 页码：131-151
• 文件大小：1.83 M

摘要

The progressively improved GSI accelerators provide beams of heavy ions from energies of 0.05–2000 A·MeV at high particle intensities now. Therefore, a wide variety of common and new heavy-ion target techniques had to be installed and developed during the past 25 years to prepare and characterize self-supported or backed heavy-ion–targets of chemical elements and compounds from hydrogen (as polyethylene) to uranium. The thickness ranged from 2×10⁻⁶ to 20 g/cm² for beam spots of about 5 mm in diameter. Homogeneity, surface structure or individual shape had to be adapted to the needs of each experiment. Special setups were required for targets of poisonous materials, of highly enriched stable isotopes or those of radioactive species in minute amounts. The capability of thin-layer technologies was as well applied to prepare and measure stripper foils or various high-vacuum deposits for experimental or accelerator purposes.

The development of different rotating target wheels and control mechanisms was enforced by the continuous change of target qualities during high-intensity heavy-ion bombardments of up to 10¹³ particles/s at Coulomb energies. The mass production of complete target systems, especially for the experiments EPOS, ORANGE and SHIP, required conditional improvement of target relevant parameters. For relativistic energies up to 2000 A·MeV at the FRS, an automated water-cooled assembly with 75 positions has been developed and installed as production target.

The brief historical review can touch only aspects of targetry at GSI. A few typical examples are included.