372596149

110

RIKEN Accel. Próg. Rep. 24 (1990)

111-5-14. Test for Dispersive-Mode Beam Transport

to the SMART Spectrograph

T. Ichihara, K. Hatanaka, H. Ohnuma, M. Yosoi, Y. Tajima, Y. Yashiro, H. Toyokawa, M. Ohura, H. Orihara, S. Kubono, M.H. Tanaka, Y. Fuchi, H. Okamura, H. Sakai, H. Shimizu, S. Hayakawa, and M. Ishihara

The spectrograph SMART was installed in the spring of 1990 in the E4 experiment room in the RIKEN Accelerator Research Facility. After the installation we started systematic diagnosis and development using a beam from the Ring Cyclo-tron. Figurę 1 shows the schematic diagram of the spectrograph SMART. We have so far suc-ceeded in obtaining some test spectra of light-ion and heavy ion direct reactions with proper particie identifications using a deuteron beam of 70 MeV/A and a ^ł5N beam of 70 MeV/A.

One of the most important requirements in operating the SMART spectrograph with high resolution is the dispersion matching of a beam transport system and a spectrograph analyzer system. The momentum resolving power of the

SMART spectrograph is anticipated to be p/ <5p = 13,000, while the momentum resolution of the beam extracted from the Ring cyclotron is expected to be 0.1% (p/<5t>=T,000). Without dispersion matching, we can expect the momentum resolution of SMART spectrograph of about p/tfp = 1,000 owing to a finite momentum spread of a beam itself. In order to get morę high resolution, we need to

(1)    achieve dispersion matching with the beam transport system and/or

(2)    cut a part of beam by the slit in the beam transport system.

In principle, dispersion matching is archived by setting a beam matrix at the counter position in the spectrograph to “achromatic”; thus the

Beam linę

Fig. 1. Schematic layout of the spectrograph SMART.