NaI(Tl) Scintillation Crystal

NaI(Tl) Scintillation Crystal for Gamma Spectroscopy

NaI(Tl) scintillation crystal, or thallium-doped sodium iodide crystal, is a widely used inorganic scintillator for gamma spectroscopy, radiation monitoring, nuclear medicine, well logging, and security detection. It offers high light yield, good energy resolution, and an emission peak around 415 nm that matches standard bialkali PMTs.

ATR Crystal supplies NaI(Tl) scintillation crystals with geometry and encapsulation reviewed for the intended instrument. Formats include cylinders, rectangular blocks, end-well crystals and X-ray type designs. Because NaI(Tl) is highly hygroscopic, the housing, reflector, optical window and sealing requirements should be defined before quotation. Specify the crystal package and its optical interface to your own photosensor.

For related materials and supply formats, review our scintillation crystals, encapsulated NaI(Tl) scintillator and CsI(Tl) scintillation crystal.

Advantages of NaI(Tl) Scintillation Crystal

• High light yieldNaI(Tl) typically provides about 38,000 photons/MeV, giving useful signal strength for gamma counting and spectroscopy.
• Good energy resolutionTypical energy resolution is about 6-7% at 662 keV, depending on crystal size, encapsulation, PMT, electronics, and test conditions.
• PMT-compatible emissionThe 415 nm emission peak is well matched to common bialkali photomultiplier tubes.
• Mature detector materialNaI(Tl) is widely used in established gamma spectroscopy, monitoring, and detector systems.
• Custom encapsulationAluminum or stainless-steel housing, optical glass or quartz windows, and reflector options can be reviewed according to the application.
• Multiple geometriesRound crystals, rectangular blocks, end-well designs and X-ray type NaI(Tl) can be reviewed according to the crystal geometry and encapsulation requirements.

Customization and Quality Control

• Drawing reviewCrystal and housing dimensions, tolerances, window material and optical coupling interface can be reviewed before quotation.
• Hermetic sealingNaI(Tl) must be protected from moisture; sealing structure and window design should match the detector environment.
• Optical matchingEmission wavelength, window material, reflector, PMT or photodetector, and optical grease requirements can be discussed.
• Visual inspectionSurface quality, housing appearance, window condition, and assembly cleanliness can be inspected according to agreed criteria.
• Performance-related testingLight output, energy resolution, or detector response can be discussed when test conditions and electronics are defined.
• Prototype and batch supportSample evaluation and repeat supply can be supported depending on geometry, material availability, and processing complexity.

Pure NaI Crystal and NaI(Tl) Encapsulation Note

For gamma spectroscopy, the standard scintillation material is NaI(Tl), or thallium-activated sodium iodide. If your RFQ uses the term pure NaI crystal scintillator, please confirm whether you mean a high-purity NaI(Tl) scintillation crystal, a bare NaI(Tl) crystal for your own encapsulation, or a sealed NaI(Tl) scintillator assembly.

NaI(Tl) is highly hygroscopic, so most detector projects require hermetic encapsulation with an optical window and reflector structure. For a complete selection explanation, see our NaI(Tl) scintillation crystal selection guide, or review the encapsulated NaI(Tl) scintillator page if you need a sealed crystal package.

Related selection guides

LaBr3(Ce) vs NaI(Tl): Gamma Spectroscopy Comparison

Energy resolution at 662 keV: calculation and specification checklist

Specifications of NaI(Tl) Crystal

The following table summarizes typical NaI(Tl) scintillation crystal properties for detector design review.

Available NaI(Tl) crystal geometries and encapsulation options.

NaI(Tl) vs. CsI(Tl) vs. BGO

NaI(Tl) is often selected for gamma spectroscopy because it balances high light yield, good energy resolution, PMT compatibility, and mature encapsulated detector design. CsI(Tl) and BGO may be preferred when photodiode readout, higher density, or non-hygroscopic handling is more important.

NaI(Tl) Crystal Formats and Encapsulation Options

Select the crystal format by active geometry, entrance window, sample position and optical output interface. An encapsulated NaI(Tl) scintillator is a sealed crystal package; its quotation scope should be defined separately from your photosensor, voltage divider and readout electronics.

Applications of NaI(Tl) Crystal

• 01

  Gamma-ray spectroscopy and isotope identification

• 02

  Environmental radiation monitoring instruments

• 03

  Well logging and geological exploration tools

• 04

  Gamma cameras and nuclear medicine systems

• 05

  Security inspection and portal monitor detectors

• 06

  Health physics survey meters and counting systems

How to Request a NaI(Tl) Crystal Quotation

For a NaI(Tl) scintillation crystal quotation, send the details needed to define the crystal and its encapsulation:

• Application, radiation energy range and intended photosensor.
• Crystal dimensions and geometry, plus any drawing or mechanical interface requirement.
• Housing, entrance window, optical output face, reflector and coupling requirements.
• Quantity, operating conditions and agreed inspection or performance-test requirements.

Crystal dimensions and the outside dimensions of a sealed housing are different specifications; identify both where relevant. Energy-resolution testing also requires the photosensor, electronics and test conditions to be defined. Final dimensions, encapsulation and acceptance criteria are confirmed for the quoted configuration.

Use the NaI(Tl) crystal inquiry form below to request a quotation, or send your drawing and requirements to sales@atrscintillator.com.

Frequently Asked Questions