Specific moments in detection of superheavy nuclei: DGFRS-2 spectrometer

Abstract

In this paper, we present the results of the first beam tests of the detection system at the focal plane of the Dubna Gas-Filled Recoil Separator-2 (DGFRS-2), which receives beams from the DC-280 FLNR cyclotron. The high beam intensity of 48Ca+10 heavy ions from the cyclotron enables us to obtain a number of superheavy recoils sufficient to compare both the measured and calculated spectra of superheavy recoils implanted into a silicon detector. A real-time algorithm to search for an Evaporation Residue (ER) — α correlated sequences is described in brief. It should be noted that the DGFRS-2 spectrometer operates in conjunction with the 48 × 128 strip DSSD (Double-sided Silicon Strip Detector; 48 × 226 mm2) detector and a low-pressure pentane-filled gaseous detector (1.2 Torr; 80 × 230 mm2). A block-diagram of the spectrometer and the event format are also presented. Special attention is paid to the response of a low-pressure pentane-filled ΔE multiwire proportional chamber for recoils of Fl, synthesized in the 242Pu + 48Ca → 287Fl + 3n complete fusion nuclear reaction. Some actual parameters of the detection system have also been extracted from natYb + 48Ca, 232Th + 48Ca, 243Am + 48Ca, 238U + 48Ca reactions. The effect of neighbor strip charge sharing for the ohmic side of the DSSD detector is also under consideration.