Scientific Review: Neutron Diffraction Activities in Serpong

Abstract

The Neutron Scattering Laboratory at Serpong is equipped with three diffractometers: a powder diffractometer (PD), a four circle diffractometer/texture diffractometer (FCD/TD) and a high resolution powder diffractometer (HRPD). The powder diffractometer (PD) was the first instrument installed (1987) by JICA/Japan and is situated in the reactor experimental hall (XHR) of the multi-purpose reactor (RSG) GA Siwabessy. The two others were installed in 1992 under phase III of the Sumitomo project, together with other neutron scattering instruments. In 1995 the PD instrument was modified to allow for residual stress measurements (RSM) in collaboration with the Japan Atomic Energy Research Institute (JAERI). The detailed activities of this instrument are explained in elsewhere in this issue. High resolution powder diffractometerThe high resolution powder diffractometer (HRPD) is a versatile diffractometer to study both crystallographic and magnetic structures of powder samples. Since X-ray diffraction is rather insensitive to light atoms such as hydrogen and oxygen, neutron diffraction is indispensable for the structure determination of materials containing such light elements. Furthermore, neutrons have an inherent magnetic moment that enables probing many kinds of magnetic structures ranging from colinear-commensurate to incommensurate configurations.The high resolution powder diffractometer (HRPD) is installed at the second neutron guide (NG2) in the neutron guide hall (NGH) about 71 meters away from the reactor core. It consists of a monochromator, collimators, a sample table, and a multicounter system. The monochromator drum has three exits corresponding to three different take-off angles: 2θ M = 41.5°, 89°, and 130°. At present the instrument is set for 2θ M = 89°. Figures 1 and 2 show the instrument and the schematic diagram of HRPD, respectively.At the beginning, a pyrolitic graphite PG(004) focusing monochromator system comprised of five PG(004) single crystals provided a focused neutron beam having a wavelength of 2.352 Å. Although two PG(002) filters had been inserted in front of the sample with the consequence of reducing the beam intensity, higher order peaks were still apparent in the diffraction pattern, which confused the analysis. Later on, to overcome this problem, a hot pressed germanium single crystal replaced the PG monochromator [1] under a bilateral cooperation between JAERI and BATAN. The Ge(331) single crystal was pressed up to 70 kgcm −2 during heating at 850°C for one hour to increase the mosaic spread. Although the Ge(331) Figure 1. The HRPD instrument.Figure 2. Schematic diagram of HRPD.

The Performance of Fine Resolution Neutron Powder Diffractometer at PTBIN-BATAN

“…As mentioned in previous paper, the present intensities and resolution of DN3 are comparable to those obtained from High Resolution Powder Diffractometer at ANSTO before they upgraded their neutron flux [9]. Here the comparison the diffraction pattern measured with DN3 and a of new HRPD (ECHIDNA) at ANSTO will be presented.…”

“…The second collimator made from vertical thin mylar films coated by gadolinium oxide with angular divergences of 20' is used after the monochromator. The 32 third collimator with angular divergence of 6', which each of them related to the one 3 He detector make the fine resolution measurement can be carried out. The details of the resolution using these collimation systems are described in the next section.…”

“…For the accurate measurement of diffracted intensity beam, the monitor counter is set before sample to monitor the incident monochromatic beam, especially if there is a fluctuation of neutron flux from the reactor in order to get a good statistically data. The detector system consists of 32 units of 3 He detectors whose diameter 25 mm. The detectors separated at equal distances by 5.0º between each other which placed in the detector bank, so that DN3 can observe a powder pattern in the scattering angle of 160º by only 100 step-scan repetitious, when the step angle of θ 2 is 0.05º in a measurement.…”

“…The two others were installed in the middle 1992 under BATANSumitomo phase III project. DN1 is now dedicated for residual stress measurement, and DN2 is for texture measurements, and DN3 is dedicated for powder measurements [3].…”

Aurivillius phases of PbBi4Ti4O15 doped with Mn3+ synthesized by molten salt technique: Structure, dielectric, and magnetic properties

“…The reactant mixtures were placed in an alumina crucible and heated to temperatures of 1023, 1123, and 1173 K for 15 h. Resulting products were washed several times using hot distilled water to remove the alkali salts and dried at 383 K for 24 h. Powder X-ray diffraction (XRD) data were collected on a Bruker D8 diffractometer using monochromatised CuKa radiation from 2y ¼101 to 1001 with a step-size of 0.021 and a counting time of 7 s per step. Powder neutron diffraction (PND) data were collected on the Fine Resolution Powder Diffractometer (DN3) [19] at The Neutron Spectrometry Division of Center for Technology of Nuclear Industry Material-BATAN, Serpong, Indonesia. The wavelength of incident neutron beam was1.8195Å.…”