About extraction of 70-GeV protons by a bent crystal from the IHEP accelerator to the PROZA setup

In 1987, during investigation the polarization effects on the experimental setup PROZA, an indication on a possible discovery of an unknown phenomenon, the scaling asymmetry, was obtained. The interval of the investigated energies was not large: from 13 GeV at BNL to 40 GeV at IHEP. It was very desirable to extend this region to the maximum of the IHEP accelerator energy 70 GeV by extracting the accelerated proton beam onto the target of the experimental setup. The extraction methods used before could not ensure the required beam parameters. It was decided to investigate a possibility of the A-70 primary beam extraction by a bent crystal. For the first time an attempt to realize such extraction was made in Dubna (1984) with the 4.2, 6.0 and 7.5 GeV beam. The first results of the 70 GeV proton extraction from the IHEP accelerator made in 1989 with the crystal of Si, installed into the vacuum chamber of magnetic block 25 and bent by 80 mrad, were reported. Since 1990 the physical use of the new method of extraction was started and a few runs of polarization experiments on the PROZA setup were done. The results of investigation both the regime of proton extraction to the PROZA setup and work of it simultaneously with extraction of the secondary particles from internal targets to other beam lines are reported