Investigation of the diamond based detectors characteristics with different thickness of the sensor element
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-01-01 |
| Journal | Journal of Physics Conference Series |
| Authors | E. V. Gladchenkov, R. F. Ibragimov, V.A. Kolyubin, P. G. Nedosekin, E. M. Tyurin |
| Institutions | National Research Nuclear University MEPhI |
| Analysis | Full AI Review Included |
6CCVD Technical Analysis & Product Brief: MPCVD Diamond for Multi-Layer Ionizing Radiation Detectors
Section titled â6CCVD Technical Analysis & Product Brief: MPCVD Diamond for Multi-Layer Ionizing Radiation DetectorsâExecutive Summary
Section titled âExecutive SummaryâThis documentation analyzes the research detailing the development and characteristics of thin-film and composite MPCVD diamond radiation detectors, focusing on the material requirements and performance for heavy ion detection.
- Detector Focus: Development of high-purity CVD IIa diamond detectors optimized for use in high-radiation environments, primarily targeting heavy charged particle flux monitoring (e.g., in long-term space missions).
- Performance Differentiation: The developed thin-film detector successfully demonstrated high selectivity, effectively registering heavy charged particles (Alpha, Fission Fragments, Kr+ ions) while being insensitive to low Linear Energy Transfer (LET) radiation (beta, gamma, neutron).
- Multilayer Advancement: A composite (multilayer) detector structure, utilizing two stacked CVD IIa plates (total thickness approx. 530 ”m), achieved a 25% increase in beta detection efficiency compared to a single-layer detector.
- Critical Challenge Identified: Testing with high-energy Kr+ ions (255 MeV) revealed strong internal polarization effects. This significantly reduced the detector output signal, indicating a measured efficiency of only 7% (Wexp/Wtheor = 0.07) relative to the theoretically deposited energy.
- Material Science Value: The work confirms the fundamental viability of stacking MPCVD diamond plates to increase sensitive detection volume, validating diamond as the material of choice for compact, radiation-hard particle sensors, provided polarization issues are addressed via material optimization.
- 6CCVD Relevance: The requirement for high-purity, precision-thickness CVD IIa films and advanced metalization services aligns directly with 6CCVDâs core manufacturing capabilities for custom Single Crystal Diamond (SCD) sensors.
Technical Specifications
Section titled âTechnical SpecificationsâHard data extracted from the experimental results regarding detector design and performance metrics.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Material Base | CVD IIa | Type | High-purity, intrinsic diamond required for detection volume |
| Composite Plate 1 Thickness | 0.35 | mm | Active SCD layer 1 dimension |
| Composite Plate 2 Thickness | 0.18 | mm | Active SCD layer 2 dimension |
| Total Multilayer Thickness | 530 (0.53) | ”m (mm) | Sum of stacked active layers |
| Applied Bias Voltage | 100 | V | Standard operating voltage for CCE measurement |
| Kr+ Ion Beam Energy (Wtheor) | 250 | MeV | Theoretical energy lost by Kr+ in diamond |
| Kr+ Observed Energy (Wexp) | 183 | MeV | Energy measured in diamond (due to nonlinear effects) |
| Kr+ Relative Efficiency (Wexp/Wtheor) | 0.07 (7) | Ratio (%) | Efficiency drop caused by strong polarization |
| Beta Detection Efficiency Increase | 25 | % | Improvement realized by the multilayer structure vs. single layer (90Sr - 90Y) |
| Alpha Particle Polarization Time | 1700 | seconds | Time required for polarization field to develop |
| Kr+ Polarization Time | 7 | seconds | Rapid polarization time under high-energy ion irradiation |
Key Methodologies
Section titled âKey MethodologiesâThe experimental approach involved precise CVD growth techniques and customized multi-layer fabrication for comparison testing under varied radiation fields.
- Diamond Synthesis: Utilized CVD IIa type diamond films, grown to specific thickness dimensions required for both thin-film (< 300 ”m) and composite structures (0.18 mm and 0.35 mm).
- Thin-Film Detector Architecture: Constructed by growing the CVD diamond film onto a diamond template. The base electrode was formed using a graphite layer contacting the template, while a metal layer served as the top electrode.
- Composite Detector Assembly: Two separate CVD IIa plates were manufactured and stacked directly one above the other. This maximized the detection volume (total 530 ”m).
- Electrode Fabrication: Metal contact layers were applied to the wide verges of both plates. The final composite detector required three electrical contacts: one on the outer verge of the top plate, one on the outer verge of the bottom plate, and a critical central contact between the two stacked diamond layers.
- Testing Environment: Detectors were tested using standard radioactive isotope sources (90Sr - 90Y for Beta, 252Cf for Alpha/Fission Fragments) and high-energy Kr+ ions (255 MeV) generated by a particle accelerator.
- Readout System: Signal acquisition utilized a metal low-noise housing, a charge sensitive amplifier, and an amplitude analyzer based on the SBS-77 processor.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research demonstrates critical material needs in precision SCD manufacturing, demanding specific thickness control, high purity, and custom metalizationâall core competencies of 6CCVD.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate and extend this high-performance radiation detection research, 6CCVD recommends materials optimized for charge carrier mobility and low defect density:
- Optical Grade Single Crystal Diamond (SCD): This material closely matches the high-purity CVD IIa specification required for maximizing Charge Collection Efficiency (CCE) and stability. Our SCD offers superior crystal quality, essential for minimizing the trap density responsible for the polarization effects observed under high-energy Kr+ ion exposure.
- High Purity Polycrystalline Diamond (PCD) Plates: For applications requiring sensitive areas larger than typical SCD limits, our inch-size PCD wafers (up to 125mm) provide exceptional uniformity and surface finish (Ra < 5nm), suitable for creating high-volume, multi-layer composite detectors.
Customization Potential
Section titled âCustomization PotentialâThe success of both the thin-film and composite detector designs hinges on precise material dimensions and specialized electrode integration. 6CCVD offers complete fabrication support to meet these engineering demands:
| Custom Requirement in Research | 6CCVD Capability | Application Benefit |
|---|---|---|
| Thin Active Layers (0.18 mm, 0.35 mm) | Precision Thickness Control | SCD and PCD thicknesses available from 0.1 ”m up to 500 ”m, allowing for exact replication or variation of the sensitive volume layers. |
| Custom Plate Dimensions (2x2 mm, 2.5x2.5 mm) | Advanced Laser Micromachining | Custom dimensioning and laser cutting to produce plates of precise geometries for complex stacking or integration into detector arrays. |
| Specialized Electrode Contacts (Metal, Graphite) | In-House Metalization Suite | Capability to deposit complex multi-layer contacts (e.g., Ohmic or Schottky barrier layers). We offer Ti, Pt, Au, Pd, W, and Cu deposition, essential for creating robust electrical connections and the multi-contact scheme used in the composite detector. |
| Requirement for High Surface Finish | Ultra-Smooth Polishing | Our SCD can achieve surface roughness (Ra) of < 1 nm, critical for ensuring uniform contact and minimizing signal loss or surface leakage current in thin-film designs. |
Engineering Support
Section titled âEngineering SupportâThe core technical challenge highlighted in the paper is the severe polarization of the diamond element under high-energy ion action. 6CCVDâs in-house PhD engineering team can assist researchers working on similar heavy ion or high-LET particle detection projects by:
- Trap Density Mitigation: Consulting on material selection (SCD vs. optimized PCD) and post-processing techniques designed to reduce deep trap concentration, thereby extending charge carrier lifetime and mitigating rapid polarization (like the 7-second time scale observed for Kr+).
- Detector Architecture Optimization: Providing guidance on optimal electrode configurations and thickness selection to maximize the Charge Collection Efficiency (CCE) stability required for long-term space mission monitoring.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
This work is devoted to study of the diamond based radiation detectors. Experiments were carried out with two types of detectors: based on a thin diamond film and on a composite diamond plate. The following types of ionizing radiation has been used in experiments: beta radiation of 90Sr - 90Y, fission fragments and alpha particles of 252Cf, and Kr ions obtained at the particle accelerator. It is shown that the developed thin-film diamond based detector effectively registers heavy charged particles, whereas beta, neutron and gamma radiation does not give a significant contribution to the detector signals. Those type of detectors are proposed for measurement of heavy charged particles linear energy transfer in diamond. The multilayer diamond based detector (detector with a composite diamond plate) showed improved charge collection efficiency values in compare with the detection with a single diamond plate.