LaBr3(Ce) Lanthanum Bromide Scintillation Detectors

1Overview

LaBr3(Ce) sets the benchmark for energy resolution among inorganic scintillators in routine production. At 662 keV (Cs-137), a 51 x 51 mm crystal achieves approximately 3.0% FWHM, well ahead of NaI(Tl) at roughly 7% and CeBr3 at approximately 4%. The photon yield is approximately 66,000 photons per MeV, and the decay time of 16 to 20 ns (size dependent) allows high count rates without excessive pile-up.

The material is hygroscopic and requires a sealed, hermetic housing. Its high refractive index (2.09 at 380 nm) is well matched to standard borosilicate and synthetic silica optical windows with appropriate coupling.

When to Choose LaBr3(Ce)

Choose LaBr3(Ce) when gamma energy resolution is the primary selection criterion. Isotope identification in complex or mixed-source fields, medical isotope quality control, and nuclear security screening all benefit from the material's sharp photopeaks and fast response. For applications where the intrinsic La-138 background at approximately 1.4 MeV would interfere with the signal of interest, CeBr3 is a lower-background alternative at the cost of slightly reduced resolution.

2Specifications

All values from the authoritative source datasheet (rev. 20-01-2025). Items marked "verify" are pending confirmation against current production data.

3Energy Resolution & Performance

LaBr3(Ce) resolves gamma lines that other scintillators blend together. The combination of high light yield, good proportionality, and fast decay makes it effective across a wide energy range. The figures below show typical spectra measured with a 51 x 51 mm crystal.

Resolution Comparison at 662 keV

4Intrinsic Background

The natural abundance of La-138 (approximately 0.09%) produces a characteristic background in the beta/gamma spectrum at a rate of approximately 2.5 counts per second per cubic centimeter in an unshielded 51 x 51 mm crystal. In addition, alpha lines above 2.5 MeV arise from the Ac-227 decay chain associated with trace actinide impurities in the lanthanum feedstock.

For most spectroscopy tasks, these features are predictable and can be subtracted with a measured background file. In extremely low-background counting or in searches for signals near the La-138 gamma at 1.4 MeV, CeBr3 is the preferred alternative. It is free of the La-138 contribution while retaining high light output and fast decay.

5Typical Applications

• Isotope identification (RIID / NORM screening): Sharp photopeaks enable confident isotope library matching in complex mixed-source fields.
• Nuclear security and border monitoring: High resolution and fast counting support rapid threat discrimination at portals and checkpoints.
• Medical isotope quality control: Resolves closely spaced gamma lines in radiopharmacy production and dose calibration.
• Environmental gamma spectrometry: Resolves Eu-152, Cs-134/Cs-137, and other environmental radionuclides that NaI blends together (background subtraction required near La-138 features).
• Nuclear research and physics: Fast decay and high rate capability suit coincidence measurements and time-of-flight experiments.
• Homeland security and defense: Used in handheld, backpack, and vehicle-mount systems where resolution and portability both matter.
• Industrial gauging and process control: High count-rate tolerance is an advantage in high-flux industrial environments.

6Available Configurations

ScintIQ LaBr3(Ce) detectors are built to order. Standard configurations cover a range of crystal sizes up to 76 mm diameter by 76 mm high. Larger custom geometries are available; contact us to verify feasibility and lead time.

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