Timing Performances and Radiation Hardness of 3D Diamond Detectors
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-08-25 |
| Authors | L. Anderlini, Marco Bellini, V. Cindro, C. Corsi, K. Kanxheri |
| Institutions | University of Florence, University of Urbino |
| Analysis | Full AI Review Included |
Analysis of 3D Diamond Detector Performance
Section titled âAnalysis of 3D Diamond Detector PerformanceâExecutive Summary
Section titled âExecutive SummaryâThis research details significant advancements in timing performance and radiation hardness achieved using 3D electrode architecture fabricated in synthetic CVD diamond, primarily for high-energy physics applications (INFN Timespot).
- Timing Performance Breakthrough: Time resolution was dramatically improved from an initial 280 ps to 80 ps, bringing the performance figure of merit close to that of mature 3D silicon technology.
- Extreme Radiation Hardness: Sensors were successfully irradiated up to a fluence level of 1016 neq (1 MeV)/cm2, demonstrating superior tolerance compared to standard planar detectors.
- Architecture Advantage: The 3D electrode design enhances both time resolution (by minimizing charge collection distance) and radiation hardness simultaneously.
- Fabrication Method: Electrodes were created using fast laser modification via multiphoton absorption, utilizing a 50 fs, 800 nm Ti:Sa laser source.
- Material Basis: The study utilized both mono-crystalline and poly-crystalline synthetic Chemical Vapor Deposited (CVD) diamond materials.
- Design Optimization: Results confirm that radiation hardness increases proportionally with increasing bulk electrode density within the 3D structure.
- Application Focus: The technology is key for detectors requiring high spatial resolution (55 ”m pitch) and ultra-fast timing in extreme radiation environments.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Achieved Time Resolution | 80 | ps | Current performance of optimized 3D diamond devices |
| Initial Time Resolution | 280 | ps | Performance before optimization/improvement |
| Target Time Resolution | Tens of | ps | Goal for high-speed particle detection |
| Spatial Resolution (Pitch) | 55 | ”m | Timespot experiment design specification |
| Maximum Fluence Tested | 1016 | neq (1 MeV)/cm2 | Neutron irradiation limit for radiation hardness study |
| Laser Pulse Duration | 50 | fs | Used for fast laser modification |
| Laser Wavelength | 800 | nm | Ti:Sa source used for electrode fabrication |
| Detector Material | Mono- and Poly-crystalline | CVD Diamond | Base material for 3D electrode architecture |
| Radiation Hardness Correlation | Increases | N/A | Observed relationship with increasing bulk electrode density |
Key Methodologies
Section titled âKey MethodologiesâThe fabrication and testing procedures focused on leveraging femtosecond laser processing to create robust 3D structures within CVD diamond.
- Material Preparation: Synthetic CVD diamond substrates were utilized, encompassing both mono-crystalline and poly-crystalline grades, selected for their intrinsic radiation tolerance.
- 3D Electrode Engineering: The 3D electrode architecture was fabricated using a technique involving fast laser modification.
- Laser Processing Parameters: A Ti:Sa laser source was employed, operating at a wavelength of 800 nm and delivering ultra-short pulses of 50 fs duration.
- Modification Mechanism: Electrode formation relied on multiphoton absorption, which induces localized graphitization (conductive pathways) within the diamond bulk.
- Performance Characterization: Devices were tested to measure timing performance, demonstrating a significant improvement from 280 ps to 80 ps.
- Radiation Testing: Sensors (including both planar and 3D designs) were subjected to neutron irradiation up to a high fluence level of 1016 neq (1 MeV)/cm2.
- Comparative Analysis: Results confirmed the superior radiation hardness of the 3D architecture over planar designs and established a correlation between increased bulk electrode density and enhanced radiation tolerance.
Commercial Applications
Section titled âCommercial ApplicationsâThe combination of extreme radiation hardness and ultra-fast timing makes 3D CVD diamond detectors suitable for demanding scientific and industrial environments.
- High Energy Physics (HEP):
- Future particle accelerator upgrades (e.g., CERN, INFN) requiring detectors capable of surviving fluences > 1016 n/cm2.
- High-rate tracking and timing layers necessary for mitigating high pile-up events.
- Space and Aerospace:
- Radiation monitoring and detection systems for satellites and deep space missions operating in high-flux environments (e.g., Van Allen belts).
- Robust sensors for long-term operation without significant performance degradation.
- Medical Imaging:
- Development of next-generation Time-of-Flight (ToF) PET scanners. The 80 ps timing resolution offers potential for superior spatial resolution and reduced patient dose compared to current technologies.
- Nuclear and Fusion Technology:
- In-situ neutron and charged particle flux monitoring within nuclear reactors or experimental fusion devices (e.g., ITER), where high temperatures and intense radiation fields preclude standard silicon use.
- High-Speed Optoelectronics:
- Ultra-fast photodetectors and sensors where minimizing charge collection time is critical for achieving high bandwidth and rapid response rates.
View Original Abstract
High time resolution and extreme radiation hardness are key for detectors to be operated in future particle accelerators and in space or medical applications. With respect to these relevant properties, we report here on performances of pixel sensors prepared on mono- and poly-crystalline synthetic Chemical Vapor Deposited (CVD) diamonds, by fast laser modification via multiphoton absorption from a 50 fs, 800 nm, Ti:Sa source. The research has been carried out in the framework of the Timespot experiment of the Italian National Institute for Nuclear Physics (INFN) aimed to achieve both high spatial resolution (55 ÎŒm pitch) and very high time resolution (tens of picoseconds) with very radiation tolerant detectors. Timespot exploits the recent 3D electrode architecture to enhance both time resolution and radiation hardness with respect to standard planar silicon and diamond detectors. We present here a major step forward in material engineering and fabrication procedure, yielding a time resolution improvement of our devices from the initial 280 ps to the present 80 ps, bringing this figure of merit very close to that allowed by the more mature 3D silicon technology. Recent results will be presented, and strategies for further improvements will be discussed. Since diamond is known to be a very radiation-tolerant material, it is considered very promising for implementing devices planned for very fast response and radiation hardness. We present results on a thorough study of polycrystalline and monocrystalline diamond sensors irradiated up to a fluence level of 1016 neq (1 MeV)/cm2. The superior radiation hardness of the 3D architecture is demonstrated with respect to the planar detectors. We have also verified that the radiation hardness increases with increasing bulk electrode density. The results are discussed and compared with other radiation hardness studies carried out on 3D diamond sensors.