We describe the details of a silicon–tungsten prototype electromagnetic calorimeter module and associated readout electronics. Detector performance for this prototype has been measured in test beam ...experiments at the CERN PS and SPS accelerator facilities in 2015/16. The results are compared to those in Monte Carlo Geant4 simulations. This is the first real-world demonstration of the performance of a custom ASIC designed for fast, lower-power, high-granularity applications.
We performed inelastic neutron scattering experiments on a multiferroic material NdFe3(BO3)4 to explore the crystal field excitations, where the magnetic anisotropy of the Nd3+ crystal field was ...responsible for the multiferroicity. Flat modes were observed at 8.5 meV and 17.4 meV in the neutron spectrum. The analysis revealed that these excitations were the transitions from the ground state to the first and second excited states of the Nd3+ crystal field.
Quantum spins in one-dimensional (1D) chains exhibit characteristic features such as the Haldane gap (S=1) and the spin-Peierls state (S=1/2). Recently multi degrees of freedom in cooperation with ...quantum spins are focused. We present here spin dynamics in the lightly hole doped Nd2-xCaxBaNiO5 (x=0.035), 1D Haldane system by means of pulsed neutron inelastic scattering method. One-magnon band with a spin gap (Haldane gap) was visible with the decrease of the zone boundary energy to 60 meV. In contrast, the spin gap slightly increases. Dynamical structures inside spin gap upon carrier doping showing incommensurate structure centered at the magnetic zone center was newly observed which is possibly originating from the doped holes in Haldane chains.
Structural change of LaH2 has been investigated at high pressure and low temperature by synchrotron radiation X-ray diffraction. LaH2 has an fcc metal lattice with interstitial hydrogen atoms located ...at tetrahedral sites. The fcc-LaH2 decomposes into two phases, which have different hydrogen compositions such as hydrogen-poor LaH and hydrogen -rich LaH2+δ phases, at 11 GPa at room temperature. In spite of largely suppressed diffusivity of the interstitial hydrogen atoms at low temperature, we have found the disproportionation reaction around 14 GPa at 200 K. Difference in the molar volume between each phases suggests monohydride LaH is formed as the disproportionation product even at low temperature. The volume fraction of the hydrogen-poor phase relative to the hydrogen-rich one at 200 K rapidly rises against pressure and reaches to ~0.45 at ~17 GPa.
The intermultiplet transitions in filled skutterudite SmFe4P12 are studied by magnetization and time-of-flight inelastic neutron scattering experiments. In neutron scattering experiments by using ...high energy neutrons for reducing huge neutron absorption of natural Sm, a small inelastic peak has been observed around ~80 meV at low temperature. The scattering vector dependence of intensity of this peak agrees with the theoretical inelastic structure factor for the intermultiplet transition from the ground J 5/2 multiplet to the excited J 7/2 multiplet in Sm3+ ion. Interestingly, the energy splitting is much smaller than the free Sm3+ ion value. This is also comparable with that estimated by the inverse magnetic susceptibility. This large reduction of the energy splitting might be due to the strong c-f mixing in SmFe4P12.
Spin Waves in Ferromagnetic Phase of MnP Itoh, S; Yano, S; Yokoo, T ...
Journal of physics. Conference series,
01/2014, Letnik:
502, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Inelastic neutron scattering experiments on an intermetallic compound, MnP, were performed by using a chopper spectrometer as well as triple axis spectrometers. Spin waves were observed in the ...ferromagnetic phase in the entire Brillouin zone along the a*- and b*-axes. The observed dispersion relations of spin waves were well described by an isotropic Heisenberg interaction adding a single ion anisotropy with two sub-lattices.
A new hybrid-type anvil device for high-pressure single-crystal neutron diffraction experiments is described. The device is composed of a large sapphire anvil and a tungsten carbide (WC) anvil which ...has a hollow in the center of the culet. In a feasibility test of the device, we could generate the pressure up to 5
GPa with high stability. As an example of the application of the hybrid-anvil device, we show some results of magnetic neutron diffraction experiments on filled skutterudite compound
PrFe
4
P
12
.
We improved the High Resolution Chopper Spectrometer (HRC), which is installed at MLF in J-PARC, in order to perform neutron Brillouin scattering (NBS) experiments, and successfully demonstrated a ...feasibility of this method. Gapless spin-wave excitations were observed in La0.8Sr0.2MnO3, which were in good agreement with previous results using single crystals, on the other hand, a large energy gap in the ferromagnetic spin waves was found in SrRuO3. Spin-wave peaks in a permanent magnet Nd2Fe14B were on the dispersion curve determined previously using a single crystal. Excitations, so-called fast sound, in liquid D2O were in a good agreement with previous inelastic neutron scattering experiments and the dispersion curve were extended to the lower Q region.
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