Journal of large-scale research facilities, 3, A103 (2017) http://dx.doi.org/10.17815/jlsrf-3-127 Published: 26.01.2017 E9: The Fine Resolution Powder Di�ractometer (FIREPOD) at BER II Helmholtz-Zentrum Berlin für Materialien und Energie * Instrument Scientists: - Dr. Alexandra Franz, Helmholtz-Zentrum Berlin für Materialien und Energie phone: +49 30 8062-42926, email: alexandra.franz@helmholtz-berlin.de - Dr. Andreas Hoser, Helmholtz-Zentrum Berlin für Materialien und Energie phone: +49 30 8062-42847, email: hoser@helmholtz-berlin.de Abstract: The E9 (FIREPOD) is an upgraded �ne resolution powder di�ractometer for elastic neutron scattering, obtaining high quality data sets for Rietveld analysis, structure solution and phase analysis under ambient conditions as well as in situ at low / high temperatures, magnetic �elds, gas pressure and various atmospheres. 1 Introduction The Fine Resolution Powder Di�ractometer E9 (FIREPOD) is an angle-dispersive powder di�ractome- ter optimized for a �at resolution function with a minimum width of the re�ections at the 2Θ-region with the highest density of re�ections. The monochromator is placed at a distance of 11 m from the reactor core, which allows for a large take-o� angle at the monochromator. An evacuated beam tube and a sapphire single crystal �lter reduce air scattering and epithermal neutrons. Neutron �ux at the sample is increased by an adjustable vertically focusing Ge-monochromator. The detector consists of eight individual DENEX 3He 2D detectors with 300 x 300 mm active area each and a common radial collimator to reduce background noise. The individual detectors are arranged in a novel setup, at optimized, non-constant distances from the sample. Five of the individual detectors can be placed close to the sample in a high intensity conformation. Data collection with �xed detector position measures parts of the 2Θ-range with increased intensity and without loss in quality. Position-sensitive data integration of the Debye cones results in a strongly reduced asymmetry of the *Cite article as: Helmholtz-Zentrum Berlin für Materialien und Energie. (2017). E9: The Fine Resolution Powder Di�rac- tometer (FIREPOD) at BER II. Journal of large-scale research facilities, 3, A103. http://dx.doi.org/10.17815/jlsrf-3-127 1 http://jlsrf.org/ http://dx.doi.org/10.17815/jlsrf-3-127 http://dx.doi.org/10.17815/jlsrf-3-127 https://creativecommons.org/licenses/by/4.0/ Journal of large-scale research facilities, 3, A103 (2017) http://dx.doi.org/10.17815/jlsrf-3-127 peaks. The 2D-data are directly accessible, allowing the early detection of preferred orientation or spot- tiness. Depending on sample scattering power and volume and the resolution settings of the instrument, full powder di�raction patterns of a quality suitable for Rietveld re�nement can be collected as fast as 30 minutes. With small 1 cm3 samples and high resolution, between 1 and 6 hours should be estimated, depending on the scattering power of the sample. Scans measuring only a selected angular with �xed detector position can be as fast as 10 minutes per step for good scatterers. Figure 1: View of E9. 2 Instrument application Typical applications are: • Crystal structure determination • Rietveld re�nement • Site occupation factors, e.g. of isoelectronic elements • Determination of light atoms (e.g. H, Li) • Rapid parameterized scans of selected angular regions of the di�raction pattern, e.g. temperature or magnetic �eld strength • Non-destructive bulk phase analysis 2 http://dx.doi.org/10.17815/jlsrf-3-127 https://creativecommons.org/licenses/by/4.0/ http://dx.doi.org/10.17815/jlsrf-3-127 Journal of large-scale research facilities, 3, A103 (2017) Figure 2: Schematic drawing of E9. 3 http://dx.doi.org/10.17815/jlsrf-3-127 https://creativecommons.org/licenses/by/4.0/ Journal of large-scale research facilities, 3, A103 (2017) http://dx.doi.org/10.17815/jlsrf-3-127 3 Technical Data Beam tube T5 Collimation α 1: 10’ or 18’ α 2: 20’ Monochromator Axially focusing, Risødesign, 300 mm height 19 Germanium composite plates with re�ecting planes (311), (511), and (711) (511) normal to crystal surface Mosaicity FWHM = 17 Take o� angle of monochro- mator 50° ≤ 2Θ ≤ 130° 111.7(1)° is used by default Wave length λ = 1.3084(2) Å from Ge(711) λ = 1.7982(1) Å from Ge(511) λ = 2.8172(2) Å from Ge(311) & PG �lter Flux ≈ 105 n/cm2s Range of scattering angles 3° < 2Θ < 142° Angle resolution 0.33° Range of lattice spacing 25 Å< d < 0.7 Å from Ge(711) 35 Å< d < 1.0 Å from Ge(511) 55 Å< d < 1.5 Å from Ge(311) d resolution ≈ 2·10−3 Sample size 1 cm3 - 5 cm3 Detector Eight area detectors (300 mm x 300 mm) Oscillating radial collimator for background reduction Polarized neutrons No Instrument options Variable sample – detector distance for �ve of the individual area detectors Sample environment OS, OF, HTF, VM3, VM5, DEGAS, RTSC Software CARESS, BEAN Table 1: Technical parameters of E9. 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Phase transitions in nanostructured potassium nitrate. Phase Transitions, 87(10-11), 1148- 1156. http://dx.doi.org/10.1080/01411594.2014.953954 Paul, A. K., Reehuis, M., Ksenofontov, V., Yan, B., Hoser, A., Többens, D. M., . . . Felser, C. (2013). Lattice Instability and Competing Spin Structures in the Double Perovskite Insulator Sr2FeOsO6. Phys. Rev. Lett., 111, 167205. http://dx.doi.org/10.1103/PhysRevLett.111.167205 Reehuis, M., Tovar, M., Többens, D. M., Pattison, P., Hoser, A., & Lake, B. (2015). Competing Jahn-Teller distortions and ferrimagnetic ordering in the geometrically frustrated system Ni1−xCuxCr2O4. Phys. Rev. B, 91, 024407. http://dx.doi.org/10.1103/PhysRevB.91.024407 5 http://dx.doi.org/10.17815/jlsrf-3-127 http://dx.doi.org/10.1080/01411594.2014.953954 http://dx.doi.org/10.1103/PhysRevLett.111.167205 http://dx.doi.org/10.1103/PhysRevB.91.024407 https://creativecommons.org/licenses/by/4.0/ Introduction Instrument application Technical Data