PROCEEDINGS
OF THE TOMSK POLYTECHNIC INSTITUTE
OF THE ORDER OF THE OCTOBER REVOLUTION AND THE ORDER
OF THE RED BANNER OF LABOR
named after S. M. Kirov

Volume 278　　　　　　　　　　　　　　　　　　　　　　　　　1975

PHYSICAL PARAMETERS OF THE “SIRIUS” SYNCHROTRON

I. P. Chuchalin, N. A. Lashuk, V. A. Vizir, P. P. Krasnosen’kikh,
Z. Sh. Faskhutdinov, M. I. Shivyrtalov

(Presented by the Scientific and Technical Seminar of the Laboratory
of High Energies of the Research Institute of Nuclear Physics)

In January 1965, at the Research Institute of Nuclear Physics, Electronics, and Automation of the Tomsk Polytechnic Institute, the “Sirius” electron synchrotron was put into operation. From the end of 1965 the accelerator began to operate for physical studies on meson photoproduction and the interaction of photons with nuclei and photoemulsions. As of January 1, 1972, the synchrotron had operated for 17,023 hours, of which 14,567 hours were devoted to physical studies and 2,456 hours to studies of accelerator physics.

The “Sirius” synchrotron is an electron accelerator with weak focusing, with a field index equal to 0.58. Four magnet quadrants are separated by straight sections 1.5 m long; in two of them are located accelerating high-frequency resonators and a goniometer for orienting the diamond target. Electrons are injected into the accelerator chamber from a microtron injector at an energy of 6 MeV, on a curved section, by means of an electrostatic inflector. The duration of the injection pulse is 3 μsec, and the current amplitude is 40 mA.

The guide magnetic field is produced by unipolar half-sinusoidal current pulses with a working-part duration of 40 msec and a frequency of up to 4 pulses per second. The number of electrons accelerated per cycle is \(2 \cdot 10^{10}\). The energy of the accelerated electrons is smoothly regulated from 200 to 1300 MeV; the energy stability is not worse than \(\pm 0.3\%\).

At present the accelerator has two photon beams of bremsstrahlung, with the Schiff spectrum from amorphous targets; one coherent (linearly polarized, quasi-monoenergetic) photon beam from a crystalline diamond target; and one light beam of synchrotron radiation.

Photon beams from amorphous targets have, at the accelerator output, an intensity of \(2 \cdot 10^9\) equivalent quanta per cycle, with an angular divergence of \(\sim 2\) milliradians. The beam from the crystalline target has an intensity of \(10^6\) quanta per cycle; the energy at the peak is regulated from 60 to 380 MeV, and the polarization at the peak is up to 40%.

The duration of the radiation pulse of the photon beams is \(0.1 \div 15\) μsec. The energy spread at short durations is

\[ \pm \frac{\Delta E}{E} = \pm 0.3\% \quad \text{and} \quad \pm 2.5\% \]

at maximum durations. By the end of 1972 a plateau will be created on the magnetic-field pulse, which will make it possible to increase the duration of the radiation pulse to 20 μsec with an energy spread no worse than \(\pm 0.1\%\). The beams are collimated twice and cleaned in a 30-kG field of charged particles, and are delivered to an experimental hall with an area of 500 m², which is separated from the accelerator by a protective wall 3.5 m thick.

At the beginning of 1973 a third photon beam from an amorphous target and an electron beam will be delivered to the experimental hall, and two beams of vacuum ultraviolet will be delivered to a separate room.