The13C(n,α0)10Be cross section at 14.3 MeV and 17 MeV neutron energy
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2017-01-01 |
| Journal | EPJ Web of Conferences |
| Authors | P. Kavrigin, F. Belloni, H. Frais-Köelbl, E. Griesmayer, Arjan Plompen |
| Institutions | CIVIDEC Instrumentation (Austria), Fachhochschule Wiener Neustadt |
| Citations | 2 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: MPCVD Diamond for Fast Neutron Spectroscopy
Section titled “Technical Documentation & Analysis: MPCVD Diamond for Fast Neutron Spectroscopy”Executive Summary
Section titled “Executive Summary”This research successfully demonstrates the superior performance of Single-Crystal Chemical Vapor Deposition (sCVD) diamond detectors for high-precision fast neutron spectroscopy, a critical requirement for nuclear fusion reactors.
- Core Achievement: Precise measurement of the ${}^{13}\text{C}(\text{n}, \alpha_0){}^{10}\text{Be}$ cross section at 14.3 MeV and 17.0 MeV, expanding the available experimental dataset for fusion applications.
- Material Functionality: The sCVD diamond acts simultaneously as the neutron interaction sample and the high-speed sensor, leveraging carbon’s inherent nuclear reactions.
- High Selectivity: A novel Pulse-Shape Analysis (PSA) technique was employed, achieving exceptional background rejection (up to 99.2% rejection in the 10-11 MeV range) to isolate specific reaction channels.
- Detector Performance: The sCVD detector exhibited excellent energy resolution (as low as 320 keV FWHM for the ${}^{13}\text{C}(\text{n}, \alpha_0){}^{10}\text{Be}$ peak at 17.0 MeV).
- 6CCVD Value Proposition: 6CCVD specializes in providing the high-purity, custom-dimensioned SCD wafers (up to 500 µm thickness) and specialized metalization required to replicate and scale these high-performance neutron detection systems.
Technical Specifications
Section titled “Technical Specifications”The following hard data points were extracted from the experimental setup and results:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Detector Material | Single-Crystal Diamond (sCVD) | N/A | Used as both sample and sensor |
| Detector Thickness | 500 | µm | CIVIDEC B1 Detector |
| Electrode Area | 4 x 4 | mm2 | Detector dimensions |
| Operating Bias Field | 1 | V/µm | Applied electric field |
| Mean Neutron Energy (1) | 14.3 ± 0.1 | MeV | Measurement angle $\theta_1 = 98^{\circ}$ |
| Mean Neutron Energy (2) | 17.0 ± 0.2 | MeV | Measurement angle $\theta_2 = 45^{\circ}$ |
| ${}^{13}\text{C}(\text{n}, \alpha_0){}^{10}\text{Be}$ Cross Section (14.3 MeV) | 10.4 ± 1.1 | mb | Derived relative to ${}^{12}\text{C}(\text{n}, \alpha_0){}^{9}\text{Be}$ |
| ${}^{13}\text{C}(\text{n}, \alpha_0){}^{10}\text{Be}$ Cross Section (17.0 MeV) | 7.1 ± 0.7 | mb | Derived relative to ${}^{12}\text{C}(\text{n}, \alpha_0){}^{9}\text{Be}$ |
| Energy Resolution (17.0 MeV) | 320 | keV FWHM | For the ${}^{13}\text{C}(\text{n}, \alpha_0){}^{10}\text{Be}$ peak |
| Background Rejection Efficiency | 99.2 | % | Achieved via PSA in the 10-11 MeV range (14.3 MeV data) |
Key Methodologies
Section titled “Key Methodologies”The experiment relied on high-quality sCVD material combined with advanced signal processing to isolate specific nuclear reaction channels.
- Neutron Source: A 7MV Van de Graaff accelerator was used with a T/Ti target (2157 µg/cm2 areal density) and a 2 MeV deuteron beam to generate quasi-monoenergetic neutrons via the $\text{T}(\text{d}, \text{n}){}^{4}\text{He}$ reaction.
- Detector Setup: A 500 µm thick sCVD diamond detector (4 mm x 4 mm) was installed 50 mm from the target and operated with a 1 V/µm electric bias field.
- Signal Acquisition: Ionization current pulses were amplified (40 dB gain, 2 GHz bandwidth) and recorded using a 1 GHz digital oscilloscope (10 GS/s sampling rate).
- Pulse-Shape Analysis (PSA): A dedicated PSA method was applied to the recorded pulses to discriminate interaction types based on:
- Amplitude Condition: Selecting interactions with energy deposition higher than the ${}^{12}\text{C}(\text{n}, 3\alpha)$ break-up.
- Drift Time Condition: Selecting interactions occurring in the “ballistic center” (minimum pulse width).
- Form Factor Condition: Selecting rectangular pulses corresponding specifically to inelastic neutron reactions.
- Simulation and Calibration: Geant4 simulations were used to model the deposited energy spectra, match them to measured data, and derive the energy conversion factor (125.3 pVs/MeV).
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials necessary to replicate, scale, and extend this critical research in neutron detection and fusion technology.
Applicable Materials
Section titled “Applicable Materials”To achieve the high resolution and fast response demonstrated in this paper, the following 6CCVD materials are required:
- Detector Grade SCD: This material is essential for replicating the core experiment. 6CCVD offers Single Crystal Diamond (SCD) wafers with thicknesses ranging from 0.1 µm up to 500 µm, matching the exact 500 µm thickness used in the study. Our high-purity SCD ensures maximum charge carrier mobility and minimal trapping, which is critical for effective Pulse-Shape Analysis (PSA).
- Polycrystalline Diamond (PCD): For scaling up detection systems (e.g., for large-area flux monitoring in fusion reactor blankets), 6CCVD offers PCD plates up to 125 mm in diameter, providing a cost-effective solution for large-scale coverage while maintaining high radiation hardness.
Customization Potential
Section titled “Customization Potential”The success of this experiment relies on precise material dimensions and reliable electrical contacts. 6CCVD offers full customization to meet these stringent requirements:
| Requirement from Paper | 6CCVD Solution & Capability | Technical Advantage |
|---|---|---|
| Custom Dimensions (4 mm x 4 mm) | Precision Laser Cutting & Custom Wafers | We provide custom-sized SCD and PCD plates, ensuring precise geometry for detector arrays or specific experimental setups. |
| High-Quality Electrodes | In-House Metalization Services | 6CCVD offers internal deposition of standard detector contacts, including Au, Pt, Pd, Ti, W, and Cu, allowing researchers to specify multi-layer stacks (e.g., Ti/Pt/Au) optimized for adhesion and low contact resistance. |
| Surface Finish | Ultra-Polishing (Ra < 1 nm) | Our SCD wafers are polished to an atomic scale (Ra < 1 nm), minimizing surface defects that can degrade energy resolution (FWHM) and affect charge collection efficiency. |
| Thickness Control | SCD Thickness Control (0.1 µm - 500 µm) | We guarantee tight tolerance control on thickness, ensuring uniformity across wafers, which is vital for reproducible detector performance and accurate energy deposition modeling (Geant4). |
Engineering Support
Section titled “Engineering Support”6CCVD’s in-house PhD team specializes in the application of MPCVD diamond for extreme environments. We can assist researchers with:
- Material Selection: Optimizing the choice between SCD (for highest resolution) and PCD (for largest area/cost efficiency) for similar fast neutron spectroscopy projects.
- Detector Design: Consulting on optimal metalization schemes and geometry to maximize charge collection efficiency and signal-to-noise ratio in high-flux environments.
- Global Logistics: Providing reliable global shipping (DDU default, DDP available) to ensure materials reach international research facilities (like EC-JRC Geel) promptly and safely.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
At nuclear fusion reactors, CVD diamond detectors are considered an advantageous solution for neutron flux monitoring. For such applications the knowledge of the cross section of neutron-induced nuclear reactions on natural carbon are of high importance. Especially the (n,α0) reactions, yielding the highest energy reaction products, are of relevance as they can be clearly distinguished in the spectrum. The 13C(n,α0)10Be cross section was measured relative to 12C(n,α0)9Be at the Van de Graaff facility of EC-JRC Geel, Belgium, at 14.3 MeV and 17.0 MeV neutron energies. The measurement was performed with an sCVD (single-crystal Chemical Vapor Deposition) diamond detector, where the detector material acted simultaneously as sample and as sensor. A novel data analysis technique, based on pulse-shape discrimination, allowed an efficient reduction of background events. The results of the measurement are presented and compared to previously published values for this cross-section.