1. from Saint Gobain studies
BrilLanCe scintillating crystals
Status of the art
from Saint Gobain studies
Perugia group 7/11/07
EMC R&D meeting

2. BrilLanCe
Cerium-doped lanthanum bromide (LaBr3(Ce))
Good density g/cc
Excellent energy resolution 3% KeV
Scintillation light yield photons/MeV
Decay time ns
Difficulties in growing crystals > 100cc due to fracturing during
cooling because of build up of internal stress.
Recently Saint Gobain >150cc, largest assembled 155cc maintain
all the properties listed above: cylindrical LaBr3(Ce 5%) 51mm diameter, 76mm length (from ingots of 130mmx120mm), plan to make a detector from the full size of the ingot
Energy res. 3.1% KeV
Light yield 165% of NaI with good uniformity over the length

3. -volumetric uniformity -crystal response to the decay of 138La
Difficult growing:due to anisotropy in thermal expansion, heat transfer and mechanical strength.
Comparison between small crystals and newly produced larger ones in terms of
-light output
-energy resolution
-energy linearity
-volumetric uniformity
-crystal response to the decay of 138La
Tested crystals
Dimension (mm)
shape
volume
quantity
4x4x5
cubic
0.08 6
4x4x15
0.24 4
4x4x30
0.48 12
13x13
cylinder
1.7
19x19
5.4 3
25x25
12.3
38x38
43.1 2
41x76
100 1
51x76
155

4. Light output
(1 means ph/MeV)
Energy resolution

5. Linearity: good up to 2.6MeV, after 4MeV loss of linearity but due to saturation in PMT (see small plot data taken with 3x optical attenuation).

6. Non uniformity studies: given ANY two points the maximum observed difference is 2.6%….

7. Natural Lanthanum contains 0.09% of
138La, 1.5 Bq/cc in LaBr3
Decays in 138Ba (66.4%) or 138Ce (33.6%)
1436KeV -ray + 32KeV Ba X-ray
789KeV -ray +  with endpoint 255 KeV
Crystal 38x38
shielded

8. From Alain Iltis (Saint Gobain)
LSO/LYSO price will not go down, dominatd by the cost of the material and by the manifacturing at high temperature.
Limited quantity of Luthetium available -> price could grow
Not less than $25/cc.
- BrilLanCe material much less expensive, seems to be very interesting but hygroscopic.
Price dominated by the manifacturing but can go down with the demand, now $40/cc
Peak emission at nm cannot be well matched by APD’s