GPPD - General Purpose Powder Diffractometer
Instrument Scientist - James W. Richardson, Jr.
Scientific Assistant -
Post Docs -
GPPD Homepage
| Beam Line |
|
F2 |
| Moderator |
|
100 K Liquid Methane |
| Wavelength Range |
|
0.2 - 5.7 Å |
| Resolution |
2q |
Dd/d (FWHM) |
|
±148° |
0.26 % |
|
±90° |
0.49 % |
|
±60° |
0.76 % |
| Beam Size |
|
1.27 cm wide, 5.08 cm |
| Detector Angles |
|
±145°, ±125°, ±90° and +60° |
| Detector Configuration |
|
144 3He counters |
| Moderator-to-Sample Distance |
|
11+12 = 25 m |
| Sample-to-Detector Distance |
|
13 = 1.5 m |
| Sample Environment |
Displex 10-300K |
Furnaces 300-1700K |
| Pressure Cell |
xxx kBar |
Sample Orienter |
GPPD is one of the three IPNS powder diffractometers which utilize time-of-flight (TOF) neutron powder diffraction (NPD). The versatility of the GPPD is exploited to resolve a diverse range of materials science problems. Multiple detector banks centered at 2q values of ±145°, ±125°, ±90°
and +60° provide measurement of anisotropy in any of a variety of structural parameters such as scattering intensity (texture), lattice parameter (anisotropic strain), and peak broadening (anisotropic micro-strain). Well-characterized peak profiles and good resolution (Dd/d
= 2.5 x 10-3 at 2q = 145°) provide sensitivity to the presence of minority phases. High temperature experiments probe chemical synthesis, phase transformations and change in strain-state. Inherent gamma radiation discrimination, extensive shielding around the instrument and remote access allow the study of highly radioactive samples. Experimental programs include structural characterization of framework modified zeolites, radiation-induced amorphization of transuranic materials, in situ electrochemistry, thermal behavior of advanced ceramic catalysts and residual stress measurement.
References:
J. D. Jorgensen et al., J. Appl. Cryst., 22 (1989) 321-333.
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