Engineering Overview

SP123 Plastic Scintillators

SP123 Plastic Scintillator is a PMMA-supported ZnS(Ag) scintillation screen designed for alpha-ray detection. ATR Crystal supplies custom SP123 panels with 4.5 mg/cm2 ZnS(Ag) coating, 0.1-10 mm PMMA substrate options, and large-area formats up to 1000 x 1000 mm for surface contamination meters, whole body contamination monitors and custom alpha detection systems.

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SP123 ZnS(Ag) Plastic Scintillator for Alpha-Ray Detection

SP123 Plastic Scintillator is a PMMA-supported ZnS(Ag) scintillation screen designed for alpha-ray detection. The active scintillating layer is silver-activated zinc sulfide, ZnS(Ag), applied to a polymethyl methacrylate substrate. This structure is used when the detector needs high alpha sensitivity, large active area and a lightweight backing material.

Because alpha particles have a very short penetration range, the ZnS(Ag) coating must be controlled for surface density, uniformity and optical collection. The standard SP123 design uses a ZnS(Ag) coating thickness of 4.5 mg/cm2, while the PMMA support substrate can be supplied from 0.1 mm to 10 mm depending on mechanical support and detector housing requirements.

ATR Crystal supplies custom SP123 alpha scintillator panels for hand-held surface contamination meters, whole body contamination monitors and large-area alpha detection systems. Panel dimensions, substrate thickness, coating area, edge processing, optical coupling, wrapping, protection method and inspection requirements can be reviewed according to your detector design.

Applications of SP123 Plastic Scintillators

Hand-held alpha surface contamination meters

Whole body contamination monitoring systems

Large-area alpha-ray detection installations

Radiological protection and nuclear safety instruments

Custom alpha detector panels and prototype assemblies

Laboratory alpha counting setups requiring ZnS(Ag) screens

Advantages of SP123 Alpha Scintillator Panels

Designed for alpha detectionThe ZnS(Ag) layer provides high scintillation response for alpha particles when used with a suitable light sensor and optical path.
Uniform coated surfaceControlled coating uniformity helps maintain consistent alpha response across the active area.
Large-area capabilitySP123 can be supplied in large panel formats up to 1000 x 1000 mm, depending on substrate, coating and handling requirements.
Lightweight PMMA supportThe PMMA substrate provides a low-density backing material with good optical clarity and practical mechanical processing.
Custom substrate thicknessPMMA thickness from 0.1 mm to 10 mm can be reviewed according to detector mechanics and optical readout design.
Detector assembly flexibilitySP123 panels can be paired with PMTs, SiPMs, photodiodes, PMMA light guides and custom housings.

SP123 Structure and Design Notes

SP123 is a coated scintillation screen. The ZnS(Ag) coating detects alpha particles, while the PMMA substrate provides mechanical support and optical transmission.

Layer / Item	Function	Design Notes
ZnS(Ag) coating	Primary alpha-sensitive scintillating layer	The standard coating surface density is 4.5 mg/cm2. Uniformity and coating area should be specified for large panels.
PMMA substrate	Mechanical support and optical backing	Substrate thickness can be 0.1-10 mm depending on rigidity, transparency, handling and housing design.
Active area	Alpha-sensitive detection surface	The active coated area should be defined separately from the total mechanical panel size if margins are required.
Readout method	PMT, SiPM, photodiode or optical module	Sensor area, light-guide geometry and coupling method influence collection efficiency.
Protection method	Open surface, protective film or housing-defined surface	Any protective layer must be reviewed carefully because alpha particles are easily stopped by surface materials.
Panel size	Custom shapes and large-area formats	Panels up to 1000 x 1000 mm can be reviewed with handling and uniformity requirements.

Properties of SP123 Plastic Scintillators

The following values are based on the original SP123 product data. Final specifications depend on substrate thickness, coating area, inspection method and detector assembly.

Property	PMMA Substrate	ZnS(Ag) Coating
Material	PMMA	ZnS(Ag)
Density	1.19 g/cm3	4.1 g/cm3
Refractive index	1.49	Not specified
Light output relative to anthracene	Not applicable	280%
Peak emission	Not applicable	450 nm
Scintillation decay time	Not applicable	200 ns
Operating temperature	-40 to 55 C	-40 to 55 C
Coating thickness	Not applicable	4.5 mg/cm2
Substrate thickness	0.1-10 mm	Not applicable
Maximum panel size	Up to 1000 x 1000 mm, depending on order requirements	Coated area and uniformity to be confirmed

Alpha Detection Considerations

SP123 should be used with the coated ZnS(Ag) surface facing the alpha source. Since alpha particles are stopped by very thin layers of material, the detector window, protective film, air gap and surface contamination must be considered during instrument design. If a protective layer is required, its thickness and material should be confirmed before ordering.

The optical readout design should match the 450 nm emission of ZnS(Ag). PMT, SiPM and photodiode selection should consider spectral sensitivity, active area, noise, expected count rate, geometry and coupling method. For large panels, light collection may require a suitable PMMA light guide, reflective wrapping or multi-sensor readout layout.

SP123 vs. Related Plastic Scintillator Products

SP123 is best understood as a ZnS(Ag)-coated alpha scintillator screen on a PMMA substrate. Other SP products use different substrates, coating structures or detection targets.

Product	Main Structure	Primary Use	Selection Notes
SP123 Plastic Scintillator	PMMA substrate with ZnS(Ag) coating, typically 4.5 mg/cm2	Alpha-ray detection and large-area contamination monitoring	Choose when an alpha-sensitive ZnS(Ag) screen with PMMA backing is required.
SP121 Plastic Scintillator	SP102 base with ZnS(Ag) coating, typically 4.5 mg/cm2	Alpha and beta radiation measurement	Choose when dual alpha/beta detection is needed.
SP122 Plastic Scintillator	SP101 base with ZnS(Ag) coating, typically 8-10 mg/cm2	Low-energy gamma detection	Choose when a coated plastic scintillator is needed for low-energy gamma response.
SP102 Plastic Scintillator	Thin polystyrene-based plastic scintillator	Beta-ray and charged-particle detection	Choose for thin beta detector designs where gamma background should pass with limited interaction.
SP101 Plastic Scintillator	Blue-emitting plastic scintillator	Gamma-ray, X-ray and general ionizing radiation detection	Choose for general plastic scintillator panels, bars, blocks and detector assemblies.
SPM100 Light Guide	Cast PMMA optical light guide	Light transfer and sensor coupling	Choose when optical coupling or geometry transition is needed, not as the active scintillator.

How to Specify SP123 Alpha Scintillator Panels

For an accurate SP123 quotation, define the total panel size, active coated area, PMMA substrate thickness, coating surface density, surface uniformity requirement, edge margin, readout method, sensor type, housing structure and whether any protective layer is required. For large-area instruments, provide drawings showing the coated side, active area, mounting holes, cable space and sensor position.

If the panel will be used in a calibrated contamination monitor, please specify the target alpha source or energy range, expected count-rate condition, active area tolerance, response uniformity requirement and any inspection method required by the instrument design.

SP123 Plastic Scintillator RFQ Checklist

Providing the following information helps ATR Crystal review feasibility and quote more accurately.

RFQ Item	Information to Provide
Application	Surface contamination meter, whole body monitor, alpha detector panel, laboratory alpha counter or custom detector assembly.
Panel geometry	Total size, active area, thickness, shape, edge margin, mounting holes and drawing.
Material structure	PMMA substrate thickness, ZnS(Ag) coating density, coated side and coating area.
Optical readout	PMT, SiPM, photodiode, light guide, reflector, optical grease or coupling requirement.
Surface requirement	Coating uniformity, surface protection, handling condition and inspection method.
Operating condition	Temperature range, humidity, cleaning method, housing design and expected mechanical stress.
Order information	Prototype quantity, batch quantity, inspection report requirement, packaging and delivery schedule.

Frequently Asked Questions

What is SP123 Plastic Scintillator used for?

SP123 is used for alpha-ray detection, especially in surface contamination meters, whole body contamination monitors, large-area alpha detection panels and custom radiological protection instruments.

What is the active scintillating material in SP123?

The active scintillating material is the ZnS(Ag) coating. The PMMA substrate provides mechanical support and optical backing.

What coating thickness is used for SP123?

The standard ZnS(Ag) coating thickness listed for SP123 is 4.5 mg/cm2. Custom coating or active-area requirements can be reviewed by project.

Can SP123 be made into large panels?

Yes. SP123 can be reviewed for large-area formats up to 1000 x 1000 mm, depending on substrate thickness, coating uniformity, handling, packaging and detector assembly requirements.

Is SP123 suitable for beta or gamma detection?

SP123 is primarily designed for alpha detection. For beta detection, SP102 or SP121 may be more appropriate. For low-energy gamma detection, SP122 may be considered depending on detector design.