Directional detection of dark matter with diamond
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-02-12 |
| Journal | Quantum Science and Technology |
| Authors | Mason C. Marshall, Matthew J Turner, Mark J. H. Ku, David F. Phillips, Ronald L. Walsworth |
| Citations | 27 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Directional Dark Matter Detection with Diamond
Section titled âTechnical Documentation & Analysis: Directional Dark Matter Detection with DiamondâExecutive Summary
Section titled âExecutive SummaryâThis research proposes a groundbreaking âhybridâ solid-state detector utilizing diamond to achieve directional detection of Weakly Interacting Massive Particles (WIMPs), pushing sensitivity below the solar neutrino floor. 6CCVD is uniquely positioned to supply the critical, high-specification diamond material required for this endeavor.
- Core Application: Directional detection of WIMP dark matter using crystal damage tracks in diamond, enabling discrimination against solar neutrino backgrounds.
- Material Requirement: Large-volume, ultra-low strain Single Crystal Diamond (SCD) is essential, requiring precise control over nitrogen and vacancy concentrations (NV centers).
- Key Technical Challenge: Localizing and mapping nanoscale damage tracks (20-50 nm length) within a micron-scale voxel using advanced NV strain spectroscopy or induced NV center fluorescence.
- Performance Benchmark: Requires achieving a strain noise floor of 1Ă10-7 and a fast readout time (target 1-3 days per mmÂł detector segment).
- 6CCVD Value Proposition: We provide the necessary high-purity, low-strain SCD substrates, custom-engineered for specific NV/Nitrogen densities, along with advanced polishing (Ra < 1 nm) and metalization capabilities (e.g., Ti/Au microcoils) crucial for implementing the proposed Quantum Diamond Microscope (QDM) and superresolution techniques.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points define the material and performance requirements extracted from the analysis of the proposed diamond WIMP detector:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Target Detector Scale | Cubic meter (mÂł) | Volume | Required total mass for sensitivity below the neutrino floor. |
| WIMP Recoil Energy Range | 10-100 | keV | Energy deposited by WIMPs in the 1-100 GeV mass range. |
| Required Spatial Resolution (3D) | <20 | nm | Necessary for nanoscale mapping of damage track directionality. |
| Expected Damage Track Length | O(10-100) | nm | Predicted length of recoil tracks from SRIM simulations. |
| Required Strain Noise Floor | 1Ă10-7 | Relative Strain | Noise floor achieved by best historical QDM measurements. |
| Voxel Localization Target | ~1 | ”m³ | Volume for diffraction-limited localization step. |
| Target Readout Speed | 1-3 | days/mmÂł | Required localization time to outpace neutrino floor event rate. |
| Large-Scale Strain Benchmark | 3Ă10-5 | Fractional Strain | Equivalent to 1 MHz NV shift; maximum acceptable intrinsic strain gradient. |
| Vacancy Count (10 keV Recoil) | ~50 | Vacancies | Number of vacancies created per low-energy WIMP event. |
Key Methodologies
Section titled âKey MethodologiesâThe proposed directional detection scheme relies on a three-step hybrid approach utilizing high-quality CVD diamond and advanced quantum sensing techniques:
- Event Registration and Triangulation: A WIMP candidate event is initially detected and localized on the millimeter (mm) scale within a segmented diamond target using traditional particle detection systems (charge, phonon, or photon collection).
- Micron-Scale Localization (QDM): The relevant diamond segment (mm³ size) is removed. A Quantum Diamond Microscope (QDM) uses NV center strain spectroscopy or induced NV center fluorescence to localize the damage track to a ~1 ”m³ voxel.
- Strain Spectroscopy: Requires NV-rich diamond and pulsed-microwave protocols to measure strain-induced shifts in NV transition frequencies, targeting 1Ă10-7 sensitivity.
- NV Center Creation: Requires high-nitrogen (Type Ib) diamond. Recoil-induced vacancies are annealed at high temperature, migrating to nitrogen impurities to form new, fluorescent NV centers, enabling background-free detection.
- Nanoscale Direction Mapping: Superresolution techniques are applied to the localized voxel to extract the particle direction from the damage track structure (<20 nm resolution).
- Optical Superresolution: Techniques like STED (Stimulated Emission Depletion) or CSD (Charge State Depletion) combined with Fourier magnetic gradient deconvolution are proposed.
- X-ray Nanoscale Measurement: Scanning X-ray Diffraction Microscopy (SXDM) is proposed as an alternative, offering 5 nm spatial resolution and 10-5 strain resolution.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe success of this directional dark matter detector hinges on the availability of large-volume, highly uniform, and precisely engineered diamond material. 6CCVD is the ideal partner to meet these stringent requirements.
Applicable Materials for WIMP Detection
Section titled âApplicable Materials for WIMP Detectionâ| Material Specification | Requirement from Paper | 6CCVD Solution |
|---|---|---|
| Single Crystal Diamond (SCD) | Large volume, ultra-low intrinsic strain (<3Ă10-5), high crystalline uniformity. | Electronic Grade SCD: Grown via MPCVD, offering superior purity and low strain necessary for quantum sensing applications. |
| Controlled NV Density (Strain Mapping) | SCD with high, uniform NV density for QDM strain measurements. | Custom SCD Doping: Precise control over nitrogen incorporation during growth to achieve optimal NV ensemble density and coherence time. |
| High-Nitrogen Diamond (NV Creation) | High-N (Type Ib equivalent) SCD with low pre-existing NV background (<1/mmÂł). | High-Purity, High-N SCD Substrates: Ideal starting material for post-growth annealing to convert recoil vacancies into new NV centers at the damage site. |
| Substrate Thickness | Segmented detector chips (mmÂł scale). | SCD/PCD Substrates: Available up to 10 mm thickness, allowing for the fabrication of the required large-volume detector segments. |
Customization Potential for Detector Fabrication
Section titled âCustomization Potential for Detector FabricationâThe proposed hybrid detector requires complex material preparation, including precise dimensions, surface quality, and integration of microfabricated components (microcoils, waveguides).
- Custom Dimensions and Segmentation: 6CCVD provides custom plates and wafers up to 125 mm (PCD) and large-area SCD. We offer precision laser cutting and dicing services to produce the required mmÂł detector segments with high accuracy.
- Ultra-Low Strain Polishing: The research emphasizes that flaws in surface processing introduce strain [39]. 6CCVD guarantees SCD polishing to Ra < 1 nm (and inch-size PCD to Ra < 5 nm), minimizing surface-induced strain that could interfere with WIMP track detection.
- Integrated Metalization: The superresolution techniques (e.g., Fourier magnetic imaging, Fig. 8) require microfabricated gradient coils and microwave guides. 6CCVD offers in-house metalization services (Au, Pt, Pd, Ti, W, Cu), allowing researchers to integrate these critical components directly onto the SCD segments.
Engineering Support
Section titled âEngineering SupportâThe development of a WIMP detector below the neutrino floor is a complex, multi-disciplinary challenge. 6CCVD acts as a technical partner, not just a supplier.
- Material Selection Expertise: 6CCVDâs in-house PhD team specializes in the relationship between CVD growth parameters, intrinsic strain, and quantum defect properties. We can assist researchers in optimizing material recipes (e.g., nitrogen concentration, growth rate, post-growth annealing protocols) specifically for directional WIMP detection projects.
- Global Logistics: We ensure reliable, global delivery of sensitive materials, offering DDU (default) and DDP shipping options to support international collaborations and shielded underground facilities.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Abstract Searches for weakly interacting massive particle (WIMP) dark matter will in the near future be sensitive to solar neutrinos. Directional detection offers a method to reject solar neutrinos and improve WIMP searches, but reaching that sensitivity with existing directional detectors poses challenges. We propose a combined atomic/particle physics approach using a large-volume diamond detector. WIMP candidate events trigger a particle detector, after which spectroscopy of nitrogen vacancy (NV) centers reads out the direction of the incoming particle. We discuss the current state of technologies required to realize directional detection in diamond and present a path towards a detector with sensitivity below the neutrino floor.