72
Growth
of a New, Fast Scintillator Crystal for Nuclear Experiments--Ceramare
Corporation, 12-D Jules Lane, New Brunswick, NJ
08901-3636; 732-937-8260
Mr.
Robert Uhrin, Principal Investigator,
Dr.
Larry E. McCandlish, Business Official,
DOE
Grant No. DE-FG02-02ER83382
Amount:
$748,845
Rare
earth orthophosphate crystals could satisfy the requirements for improved
scintillators needed for nuclear physics experiments.
These requirements include fast decay time (approximately 30 nsec with no
slow component), greater light output compared to current materials, a radiation
length less than 2 cm, and the ability to be grown in a large size.
All of these requirements could be met at reasonable cost if a suitable
solvent system and growth technique could be identified for cerium-doped
gadolinium orthophosphate. In this
project, a new solvent system will be studied to identify the solution region
from which cerium-doped gadolinium orthophosphate can be grown.
The solution characteristics and phase relationships for this system will
be investigated to determine the feasibility of growing large cerium-doped
gadolinium orthophosphate crystals by top-seeded solution growth.
In Phase I, fourteen solution compositions were studied to determine the
solid phases present. The amount of
solid precipitate, its phase composition, and its crystal morphology were
determined by x-ray diffraction and microscopy techniques. Conditions
for the formation of phase-pure GdPO4 crystals were determined, and small
crystals of cerium-doped GdPO4 were grown. Phase
II will develop and optimize a top-seeded solution growth technique for growing
large cerium-doped crystals. The
cerium concentration will be optimized for maximum light output. Scintillator
elements will be fabricated and polished to determine spectroscopic properties.
Commercial Applications and Other Benefits
as described by awardee: Cerium-doped
gadolinium orthophosphate should have better characteristics than cerium doped
gadolinium orthosilicate, which is a major scintillator crystal utilized in
positron emission tomography. The
growth technology for this orthophosphate crystal would allow the possibility of
incorporating a series of rare earth analog crystals into many commercial laser
systems.