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 CsI:Tl coupled to suitable photo-detectors have exhibited excellent energy resolution of less than 8% 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 CsI:Tl. Single crystals of CsI: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 CsI:Tl crystals and fabricate scintillator detectors using photo-diodes as well as PMTs.

SPECIFICATIONS

APPLICATIONS

• Gamma-ray spectrometer
• High energy radiation detectors
• Nuclear Physics Experiments
• Area monitor
• Medical imaging
• Security baggage scanning

INTRODUCTION

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 CsI:Tl coupled to suitable photo-detectors have exhibited excellent energy resolution of less than 8% at 662 keV, suitable to be used as radiation detectors in gamma-ray spectroscopy applications. The CsI:Tl being less hygroscopic in nature is easier to handle compared to NaI:Tl crystal. Secondly, the emission from CsI:Tl scintillator at 550 nm makes it suitable to be coupled to photo-diodes to fabricate compact devices operating at lower voltages compared to PMT. 

BARC has developed a novel crystal growth system based on the modified Bridgman technique to grow high quality, crack-free single crystals of CsI:Tl. Easy extraction of the grown crystal is achieved using a uniquely designed silica crucible and an ingenious furnace design that has precise temperature control mechanism and highly accurate motor for lowering the crucible. Single crystals of CsI:Tl up to 50 mm in diameter and 60 mm in length could be grown with almost 100% yield. The technology also covers processing of the grown CsI:Tl crystals and fabrication of scintillator detectors using photo-diodes as well as PMTs.

SPECIFICATIONS

APPLICATIONS

• Gamma-ray spectrometer
• High energy radiation detectors
• Nuclear Physics Experiments
• Area monitor
• Medical imaging
• Security baggage scanning

REQUIREMENTS FOR COMMERCIAL PRODUCTION

• Infrastructural Requirements

Space

About 600 sq feet (25x25 sq. ft) roofed area with proper arrangement of cleanness (preferably Class 10,000), dust proof with controlled temperature (25±1°C) and humidity (<55%) with continuous electricity.

Equipment

• Growth Furnace
• Dehydration unit
• Weighing balance
• Cutting machines
• PMT and associated electronics for testing
• Glass blowing facility for sealing
• Laminar flow bench
  

Consumables

• Vacuum desiccators
• Quartz crucible
• Raw material
• Process chemicals (alcohol, optical grease, oil)
• Emery papers
• Alumina powder

• Manpower Requirement
  • One B.Sc. (Physics) and one M.Sc. (Physics) or equivalent degree
    
    
    
• Power Supply Requirement
  • 220 V, 50 Hz, Single phase, 15 A