Technology to Grow Single Crystals of NaI:Tl and
Fabrication of Radiation Detectors

Single crystals of alkali halide inorganic scintillators are useful as nuclear radiation detectors in gamma-ray spectroscopy and radiography applications. These crystals are grown in silica crucibles using the vertical Bridgman technique. Crystals of NaI:Tl coupled to photo-multiplier tubes have exhibited excellent energy resolution of less than 7% at 662 keV, suitable to be used as radiation detectors in gamma-ray spectroscopy for the identification of radio-active nuclides.

BARC has developed a novel crystal growth system based on the modified Bridgman technique to grow high quality, crack-free single crystals of NaI:Tl. Single crystals of NaI:Tl up to 50 mm in diameter and 60 mm in length could be grown with almost 100% yield. Expertise has been developed to process the grown NaI:Tl crystals and fabricate scintillator detectors using photo-multiplier tubes (PMT).

  • Crystal dimension (mm)

: Diameter : 50 mm,
: Length : 60 mm

  • Density [g/cm3]
: 3.67
  • Melting point [°C]
: 651
  • Energy resolution
: Less than 7% at 662 keV
  • Hygroscopic
: Yes
  • Wavelength of emission max. [nm]
: 420
  • Light yield [photons/keVγ]
: 38
  • Primary Decay time (ns)
: 250


    For details contact :

        Head, Technology Transfer & Collaboration Division,
        TROMBAY, MUMBAI - 400 085
        Fax : 091-022-25505151
        Email :