THE FIRST EXPERIMENTS OF THE 10 MHz POSITION SENSITIVE DETECTOR "OD-3". V.M. Aulchenko, Yu.S. Velikzhanin, V.M. Titov, S.A. Ponomarev, Yu.V. Usov, M.S. Dubrovin, B.P. Tolochko^*, Yu.A. Gaponov^*, O.V. Evdokov^*. Budker Institute of Nuclear Physics, M.Lavrentev st. 11, Novosibirsk-90, 630090 Russia; ^*Institute of Solid State Chemistry, Kutateladze st.18, Novosibirsk-128, 630128 Russia

A history of the development of position sensitive (PS) detectors for x-ray experiments in Novosibirsk INP started since 1975. An old OD-2 modification was relatively simple device based on the proportional chamber with a delay line for the coordinate reconstruction.

The development of a new detector was started two years ago and was stimulated by the users request to improve pointed out parameters. A completely new one coordinate detector OD-3 was designed to improve the parameters of the OD-2.

OD-3 has the following parameters:

- frequency up to 10 MHz events/detector;

- angular resolution 0.009 degree (near ~100 mkm);

- parallax-free at variable focal length (from 300 mm to 450 mm without any

modification and to infinite at cathode plane replacement);

- photoabsorbtion region increased up to 50 mm (and can be increase more);

- enlarged inlet window up to 200 mm x 10 mm.

In the July 1995 the OD-3 was tested at the synchrotron radiation beam line 5-b storage ring VEPP-3. From the January 1996 OD-3 is using in the time-resolved diffraction experiment for the investigation the synthesis of the NiMoO₄, CaMoO₄, the intercalation of the sodium adipate into LiCl*2Al(OH)₃*nH₂O and reduction of the Ag from the metal-organic compounds.