SP121 Plastic Scintillators
SP121 Alpha Beta Plastic Scintillator for Surface Contamination Detection
SP121 Plastic Scintillator is a coated plastic scintillator designed for dual alpha and beta radiation measurement. It uses an SP102 polystyrene-based plastic scintillator as the substrate and a controlled ZnS(Ag) coating layer for alpha response. In this structure, the ZnS(Ag) coating is responsible for alpha detection, while the SP102 substrate supports beta-particle detection.
The standard SP121 coating thickness is 4.5 mg/cm2. Because alpha particles have a very short penetration range, coating density, surface uniformity, detector window and protective layer design must be reviewed carefully. The beta response depends on SP102 thickness, source energy, detector geometry, optical coupling, sensor sensitivity and electronics.
ATR Crystal supplies custom SP121 scintillator screens and panels for surface contamination detectors and alpha/beta monitoring instruments. Panel dimensions, active area, SP102 thickness, ZnS(Ag) coating, readout method, light-guide structure, wrapping, housing and inspection requirements can be reviewed according to your instrument design.
Applications of SP121 Plastic Scintillators
Alpha/beta surface contamination detectors
Portable radiation survey instruments
Radiological protection and contamination monitoring
Laboratory alpha/beta counting assemblies
Custom coated scintillator detector panels
Prototype detector modules requiring dual particle response
Advantages of SP121 Alpha Beta Scintillator Screens
- Dual alpha/beta measurementThe ZnS(Ag) layer provides alpha response, while the SP102 plastic scintillator substrate supports beta detection.
- Controlled ZnS(Ag) coatingThe 4.5 mg/cm2 coating is designed for alpha-particle absorption and scintillation response in surface contamination monitoring.
- Fast SP102 substrateThe SP102 substrate provides a 423 nm emission peak and 2.4 ns decay time, supporting fast beta detection designs.
- Good uniformityCoating uniformity and substrate quality can be specified to support consistent response over the active area.
- Custom panel formatsCustom active area, substrate thickness, edge margin, panel shape and mounting features can be reviewed with drawings.
- Detector integration supportSP121 can be reviewed with PMT, SiPM, photodiode, light-guide, reflector, wrapping and housing requirements.
SP121 Structure and Detection Function
SP121 is a layered alpha/beta scintillator structure. The coated side, detector window and optical readout must be defined clearly for practical detector design.
| Layer / Item | Function | Design Notes |
|---|---|---|
| ZnS(Ag) coating | Alpha-sensitive scintillating layer | Standard coating surface density is 4.5 mg/cm2. The coated surface should face the alpha source unless the detector design specifies otherwise. |
| SP102 substrate | Beta-sensitive plastic scintillator base | SP102 supports beta-particle detection and provides mechanical backing for the coated screen. |
| Coated side | Defines alpha response direction | Alpha particles are easily stopped by thin materials, so any window, film or protective layer must be reviewed. |
| Optical readout | PMT, SiPM, photodiode or optical module | The sensor should match emission around 423 nm from SP102 and 450 nm from ZnS(Ag). |
| Signal handling | Instrument-level alpha/beta measurement | Electronics, threshold settings and calibration determine how alpha and beta signals are interpreted. |
| Panel format | Custom plate, screen or detector panel | Active area, total size, substrate thickness, mounting holes and edge margin should be defined in the drawing. |
Properties of SP121 Plastic Scintillators
The following values are based on the original SP121 product data. Final specifications depend on substrate thickness, coating process, active area and inspection method.
| Property | SP102 Substrate | ZnS(Ag) Coating |
|---|---|---|
| Material | SP102, polystyrene-based plastic scintillator | ZnS(Ag) |
| Density | 1.023 g/cm3 | 4.1 g/cm3 |
| Refractive index | 1.58 | Not specified |
| Light output relative to anthracene | 64% | 280% |
| Maximum emission wavelength | 423 nm | 450 nm |
| Scintillation decay time | 2.4 ns | 200 ns |
| Operating temperature | -40 to 55 C | -40 to 55 C |
| Coating thickness | Not applicable | 4.5 mg/cm2 |
| Detection role | Beta-particle detection | Alpha-particle detection |
Alpha/Beta Detector Design Considerations
SP121 should be specified as part of the full detector assembly. For alpha detection, the ZnS(Ag) coated side must be exposed appropriately because alpha particles are stopped by very thin materials. For beta detection, the substrate thickness, beta energy, source distance, detector window and electronic threshold all affect the measured response.
SP121 is suitable for contamination monitoring and screening applications where alpha and beta sensitivity are required. If the instrument needs energy spectroscopy, isotope identification or high-efficiency gamma response, inorganic scintillators or specialized detector structures may be more appropriate.
SP121 vs. Related Plastic Scintillator Products
SP121 should be selected when a single coated screen is needed for alpha and beta surface contamination measurement. Other SP products target alpha-only screens, low-energy gamma response, beta detection, general plastic scintillation or optical coupling.
| Product | Main Structure | Primary Use | Selection Notes |
|---|---|---|---|
| SP121 Plastic Scintillator | SP102 base with ZnS(Ag) coating, typically 4.5 mg/cm2 | Alpha and beta radiation measurement | Choose for surface contamination detectors requiring dual alpha/beta response. |
| SP123 Plastic Scintillator | PMMA substrate with ZnS(Ag) coating, typically 4.5 mg/cm2 | Alpha-ray detection | Choose for alpha-sensitive ZnS(Ag) screens and large-area alpha monitoring panels. |
| SP122 Plastic Scintillator | SP101 base with ZnS(Ag) coating, typically 8-10 mg/cm2 | Low-energy gamma detection | Choose for low-energy gamma monitoring and portable radiation instruments. |
| SP102 Plastic Scintillator | Thin polystyrene-based plastic scintillator | Beta-ray and charged-particle detection | Choose for beta detection when no alpha-sensitive ZnS(Ag) layer is needed. |
| SP101 Plastic Scintillator | Blue-emitting plastic scintillator | Gamma-ray, X-ray and general ionizing radiation detection | Choose for uncoated plastic scintillator panels, blocks, bars 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 SP121 Alpha Beta Scintillators
For an accurate SP121 quotation, define the total panel size, active area, SP102 substrate thickness, ZnS(Ag) coating surface density, coated side, coating uniformity, detector window, readout method, light-guide requirement, reflector, housing design and calibration plan.
If the detector is used for contamination monitoring, provide the target alpha and beta sources, expected energy range, response uniformity requirement, active area tolerance, mounting method and any instrument standard or inspection report requirement.
SP121 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 detector, alpha/beta survey instrument, laboratory counter or custom detector assembly. |
| Radiation target | Alpha source, beta source, energy range, threshold requirement and measurement geometry. |
| Panel geometry | Total size, active area, substrate thickness, shape, edge margin, mounting holes and drawing. |
| Material structure | SP102 substrate requirement, ZnS(Ag) coating thickness, coated side and coating area. |
| Optical readout | PMT, SiPM, photodiode, light guide, reflector, optical grease or coupling requirement. |
| Inspection requirement | Coating uniformity, visual inspection, alpha/beta response uniformity, reference source and report format if required. |
| Order information | Prototype quantity, batch quantity, packaging requirement and delivery schedule. |
