The SunSILICON™ P from Sun Nuclear is a shielded p-type silicon diode detector designed for precision relative dosimetry in cylindrical water phantoms. It is Sun Nuclear’s new generation of shielded detectors, replacing the EDGE Detector with significant improvements in water equivalence, radiation hardness and field size range. The “P” denotes the shielding, with a shield symbol engraved on the housing for easy identification.
Key Features
- Custom shielded, fully guarded p-type silicon diode
- 0.053 mm³ active volume for high spatial resolution
- 38 nC/Gy sensitivity for fast scanning speeds
- HE Solid Water® housing — water-equivalent for minimal perturbation
- Integrated shielding for a flat photon energy response
- Radiation hardness and leakage characteristics superior to the EDGE Detector
- Low dose-per-pulse dependence
- Tight mechanical tolerances for detector-to-detector consistency
- Alignment marks and shield symbol engraved on the housing
- Waterproof
- Compatible with IMRT, SRT and IGRT techniques
Applications
- Small to large field photon dosimetry (2×2 to 40×40 cm²)
- Linear accelerator commissioning
- Small-field output factor measurement (per IAEA TRS-483 / AAPM TG-155)
- Beam lateral profiles and PDDs
- Ideal for applications where a flat photon energy response is critical
Compatibility
Compatible with Sun Nuclear’s SunSCAN™ 3D and 3D SCANNER™ water scanning systems. BNC or TNC connector available.
SunSILICON vs SunSILICON P
The SunSILICON P (shielded) is optimised for photons with a flat energy response, covering fields from 2×2 to 40×40 cm². For very small field dosimetry (down to 0.4×0.4 cm²) or electron dosimetry, see the SunSILICON™ (unshielded).
EDGE Detector evolution
The SunSILICON P replaces the EDGE Detector (model 1118, end-of-life) in the medium to large field range, with substantial improvements: Solid Water housing (was brass), correction factors within ±2% across almost the entire usage range, and superior radiation hardness.
Technical Specifications
| Model | 1049 |
| Detector type | Shielded p-type silicon diode |
| Active volume | 0.053 mm³ |
| Sensitivity | 38 nC/Gy |
| Field size range (photons) | 2×2 to 40×40 cm² |
| Minimum field size | 1.2×1.2 cm² |
| Water-equivalent build-up | 1.25 mm |
| Reference point | 1 mm from top surface |
| External dimensions | 8.22 mm × 59 mm (diameter × length) |
| Cable length | 1.5 m |
| Connector | BNC or TNC |
| Impedance | > 1000 MΩ |
| Output polarity | Negative |
| Housing | HE Solid Water® (water-equivalent) |
Scientific evidence
The dosimetric performance of the SunSILICON and SunSILICON P is documented in peer-reviewed literature. The study by Schönfeld et al. (Journal of Applied Clinical Medical Physics, 2026) characterises the small-field output correction factors (field output correction factors) and decomposes their origin through perturbation factor analysis — volume, density and medium — combining experimental measurements with Monte Carlo simulation.
The results confirm that both detectors meet the recommendations of the IAEA TRS-483 and AAPM TG-155 protocols for small-field dosimetry, with correction factors within the 5% limit required for accurate output factor measurement. The SunSILICON (unshielded) covers fields from (1×1) to (10×10) cm² in photons; the SunSILICON P (shielded) extends the range up to (40×40) cm², keeping correction factors low across the whole interval.
This scientific basis makes the SunSILICON a validated choice for commissioning and QA of photon and electron beams in radiotherapy, including very small-field stereotactic techniques.
References: Schönfeld A. A. et al., “Field output correction factors and perturbation factor analysis for the novel SunSILICON and SunSILICON P silicon diode detectors”, Journal of Applied Clinical Medical Physics, 2026. See also the AAPM poster Field Output Correction Factors of Novel Unshielded and Shielded Silicon Diode Detectors.
