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X-Ray Diffraction(XRD)

Facility News

New Bruker DISCOVER D8 X-ray diffraction system has been moved from Marshak to CDI and successfully reinstalled. Both high resolution (HR) and powder diffraction (PD) configurations are available for measurements. HR configuration utilizes 0-D scintillator counter and 1-D position sensitive (LYNXEYE) detectors (the LYNXEYE allows fasten up some measurements). HR configuration is mostly used for thin films characterization (rocking curves, reciprocal space mapping, precision 2Theta - Omega and Phi scans). PD configuration comprises unique large area VANTEC-500 detector. This configuration is excellent tool for crystal orientation, minerals and rocks study (phase identification by microdiffraction), texture measurements (pole figures).  Facility location – CDI 4.228.

PANalytical  X'Pert Pro Powder Diffraction instrument has been upgraded with new fast detector (PIXcel1D), diffracted beam monochromator, and sample changer.  For more information download the XRD Upgrade Notes and updated SOP (see links below).

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PANalytical X'Pert Pro powder diffractometer

  • Location:
    Marshak Science Building, Room: 904
    The City College of New York
    160 Convent Ave, New York, NY 10031
  • Staff:
    Dr. Alexey Bykov: Phone: 212 650 5548.  Cell: 646 725 0270
  • Scheduling:
    For access to online calendar please click here.

Fees

New rates effective 12/01/16

Federal rate - $10/h
Non-Federal rate - $34/h
CCNY rate - $5/h

Facility Images

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About the facility

This XRD instrument from Panalytical is used primarily for powder diffraction. The X’Pert powder instrument is configured with simple slits and proportional detector for data collection to do phase analysis including Rietveld refinement. The built-in structural database (PDF) allows identification of phases from powder diffraction data.

Features

  • X-ray source: Philips high intensity ceramic sealed tube (3kW)
  • Wavelength: Cu Ka (1.5405 Å)
  • Incident beam optics: Soller slit (0.04 rad), interchangeable divergence fixed slits and masks.
  • Diffracted beam optics: Soller slit (0.04 rad), Ni-filter, interchangeable fixed antiscattering and receiving slits.
  • Detector: sealed proportional counter
  • Sample stage: fixed stage and spinner
  • Software: Data Collector,  HighScore (Plus)

 

Background: X-ray powder diffraction

Powder XRD (X-ray Diffraction) is one of the most widely used x-ray diffraction technique for characterizing materials. The sample is supposed to be in a powdered form (as it follows from the name of the technique) consisting of fine single crystalline grains of material to be studied. The technique is used also for analyzing particles in liquid suspensions or polycrystalline solids (bulk or thin film materials).

The atoms in a crystal are a periodic array of coherent scattering centers and thus can diffract light. Interaction of X-rays with powdered sample creates secondary “diffracted” beams (actually generated in the form of cones) of X-rays related to interplanar d-spacings in the crystalline powder according to Bragg’s Law: nλ = 2d sinθ, where n is an integer, λ is the wavelength of the X-rays, d is the interplanar spacing generating the diffraction, and θ is the diffraction angle.

Powder diffraction data can be collected using either transmission or reflection geometry. Because the particles in the powder sample are randomly oriented, these two methods will yield the same data.

Useful Links

X'Pert Pro XRD SOP

PIXcel Upgrade Notes