CLYC Gamma-Neutron Scintillator

CLYC 3CLYC (Cs2LiYCl6:Ce) is a dual-mode gamma-neutron scintillator and the first practical detector for use as a replacement for both medium resolution gamma-ray detectors and Helium-3 proportional counter tubes for neutron detection. The ease of using Pulse Shape Discrimination (PSD) for neutron detection, combined with better gamma-ray resolution than Sodium Iodide (NaI) or Caesium Iodide (CsI), make the CLYC detector an ideal solution for several classes of handheld instruments, including Personal Radiation Detectors (PRDs), Spectroscopic Personal Radiation Detectors (SPRDs), and Radioisotope Identification Devices (RIIDs).

CLYC Properties   CLYC Configurations  Contact RMD

  • Material: Cs2LiYCl6:Ce
  • Melting Point: 640°C
  • Density: 3.31 g/cm3
  • Crystal Structure: Cubic
  • Cleavage planes: None
  • Water Solubility: Hygroscopic
  • Refractive Index: 1.81 ± 0.037 @ 405 nm
  • Coefficient of Thermal Expansion: 34.34×106/°C @ 30°C
  • Emission Spectral Range: 275 – 450 nm
  • Peak Scintillation Wavelength: 370 nm
  • Decay Constants (CVL. Ce3+, Ce-STE): 1 ns, 50 ns, 1000 ns
  • Scintillation Light Yield: 20,000 ph/MeV
  • GEE for Thermal Neutrons: 3.2 MeV
  • X-ray Absorption Coef. at 100 KeV: 3.97 cm·1
  • X-ray Absorption Coef. at 662 KeV: 0.251 cm·1
  • Radiation Length: 3.42 cm
  • Heat Capacity: 0.379 J/(g*K)
  • Thermal Conductivity: 0.0067 W/(cm *K) at 50°C


  • 25mm (1″) diameter/25mm (1″) long cylinder
  • 38mm (1.5″) diameter/38mm (1.5″) long cylinder
  • 50mm (2″) diameter/50mm (2″) long cylinder
  • 75mm (3″) diameter/75mm (3″) long cylinder
  • 75mm (3″) diameter/101mm (4″) long cylinder
RMD’s 75mm x 175mm (3″ x 7″) CLYC boule

Package Style

  • Sealed package
  • Sealed package and permanently mounted to a photomultiplier tube (PMT)
  • Permanently packaged to SiPM arrays with temperature sensors

CLYC Packaged Scintillation Detector   CLYC Packaged to SiPM Array with Temperature-Sensors

Energy Resolution

<= 5% FWHM at 662keV line of 137Cs
(obtained at 220C with an appropriate PMT and integration time constant on the pulse height electronics)

CLYC Spectral Chart
Neutron/gamma Pulse Shape Discrimination (PSD) scatter plot of a 3” x 3” CLYC cylinder measured under a 241Am/Be neutron source.
CLYC Spectral Chart
137Cs pulse height spectrum of a 2” x 2” CLYC