Combining γ-ray and particle spectroscopy with SONIC@HORUS

Abstract

The particle spectrometer SONIC for particle-γ coincidence measurements was commissioned at the Institute for Nuclear Physics in Cologne, Germany. SONIC consists of up to 12 silicon ∆E-E telescopes with a total solid angle coverage of 9 %, and will complement HORUS, a γ-ray spectrometer with 14 HPGe detectors. The combined setup SONIC@HORUS is used to investigate the γ-decay behaviour of low-spin states up to the neutron separation threshold excited by light-ion inelastic scattering and transfer reactions using beams provided by a 10 MV FN Tandem accelerator. The particle-γ coincidence method will be presented using data from a 92 Mo(p,p'γ) experiment. In a 119 Sn(d,X) experiment, excellent particle identification has been achieved because of the good energy resolution of the silicon detectors of approximately 20 keV. Due to the non-negligible momentum transfer in the reaction, a Doppler correction of the detected γ-ray energy has to be performed, using the additional information from measuring the ejectile energy and direction. The high sensitivity of the setup is demonstrated by the results from a 94 Mo(p,p'γ) experiment, where small γ-decay branching ratios have been deduced.

Shape coexistence and collective low-spin states in Sn112,114 studied with the (p,p′γSpieker1, Petkov2, Литвинова3 et al. 2018Phys. Rev. C180201View full textAdd to dashboardCite

“…The combined spectroscopy setup SONIC@HORUS used for the pγ-coincidence experiments consists of passivated implanted planar silicon (PIPS) detectors and up to 14 high-purity germanium (HPGe) detectors. Six of these can be equipped with BGO shields for active Compton suppression [14]. The current on target accounted to about 5 nA with a master-trigger rate of up to 25 kHz, which corresponded to operating the silicon and germanium detectors at maximum count rates of about 11 kHz and 15 kHz, respectively.…”

“…The SONIC chamber, i.e. SilicON Identification Chamber, which was used in these experiments was the second SONIC version housing seven silicon detectors in total [14]. A precise energy calibration of the HPGe detectors is crucial for any DSA lifetime measurement.…”

“…[11,13] and references therein. In contrast, the new (p, p ′ γ) DSA coincidence technique with the SONIC@HORUS setup [14] at the University of Cologne (Germany) detects the scattered protons in coincidence with the γ-rays emitted from the excited state to determine nuclear level lifetimes without feeding contributions [15]. A further advantage of this method is that much less target material is needed compared to the (n, n ′ γ) experiments.…”

Low-energy excitations and $$\gamma $$-decay branchings in $$^{124}$$Sn via (p,p’$$\gamma $$) at $$E_p={15}\,\,\hbox {MeV}$$

“…The 124 Sn(p,p'γ ) experiment was performed at the Institute for Nuclear Physics of the University of Cologne. The 15 MeV proton beam was provided by the 10 MV FN Tandem accelerator and directed to the combined spectroscopy setup SONIC@HORUS [29].…”

“…To detect the scattered protons, twelve PIPS (Passivated Implanted Planar Silicon) detectors were mounted inside the SONIC chamber using a modular holding frame. Azimuthal angles of 45 • , 135 • , 225 • , and 315 • are covered for polar angles of 107 • and 145 • while the azimuthal angles of 0 • , 90 • , 180 • , and 270 • are covered for a polar angle of 123 • [29]. For the present experiment, HORUS consisted of thirteen high-purity germanium (HPGe) detectors of which six were additionally equipped with BGO shields for active Compton suppression.…”