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Research and Development of Diamond Based Beam Monitoring and Diagnostics Systems at the S-DALINAC

MetadataDetails
Publication Date2017-01-01
JournalTUbilio (Technical University of Darmstadt)
AuthorsA. Rost, T. Galatyuk, Jerzy Pietraszko
AnalysisFull AI Review Included

Technical Documentation and Analysis: Diamond Based Beam Monitoring Systems

Section titled “Technical Documentation and Analysis: Diamond Based Beam Monitoring Systems”

This research paper validates the application of high-purity Single Crystal CVD (scCVD) diamond as the definitive material for high-rate, radiation-hard beam monitoring and diagnostics in high-energy physics (HEP) accelerators (e.g., S-DALINAC, FAIR/CBM).

  • Core Value Proposition: Single Crystal Diamond (SCD) is essential for achieving critical Time-of-Flight (ToF) timing precision (< 50 ps) while sustaining unprecedented radiation loads (up to 109 ions/s).
  • Material Requirement: The system demands ultra-high purity, mono-crystalline diamond to ensure maximum Charge Collection Efficiency (CCE), which is mandatory for reliable Minimum-Ionizing Particle (MIP) detection.
  • Detector Configuration: Position sensitivity is achieved through diamond mosaic detectors (e.g., 14 mm x 14 mm total area) utilizing stripped read-out electrodes.
  • Electronic Performance: The custom FPGA-based TRB3/PADIWA read-out architecture supports multi-hit Time-to-Digital Converters (TDCs) with high precision (RMS < 12 ps).
  • Engineering Focus: Successful implementation requires close collaboration between material scientists and electronics engineers to perfectly match the SCD pre-amplifier specifications to the analog front-end stage.
  • Future Scope: Installation of a dedicated permanent test facility is planned, requiring SCD samples optimized for electron beams up to 130 MeV.

The following table extracts the hard performance metrics and material constraints required for advanced diamond-based beam monitoring systems described in the research.

ParameterValueUnitContext
Target Timing Resolution ($\sigma_{ToT}$)< 50psPrecise Time-of-Flight (ToF) measurement target
Beam Rate Requirement (CBM)Up to 109ions/sDriving requirement for extreme radiation hardness
Readout Precision (FPGA-TDC RMS)< 12psPrecision of the TRB3 multi-hit DAQ system
Material TypeSingle Crystal CVD (scCVD)N/ASelected for high drift velocity and CCE
Detection TargetMinimum-Ionizing Particles (MIPS)N/ARequires optimal material purity and low structural defects
Example Mosaic Area14 x 14mm2Total area of the diamond based mosaic detector
Electron Beam Energy (Test Setup)Up to 130MeVMaximum energy for detector studies at S-DALINAC
Desired Test Beam CurrentSeveralnARequired parameter for new detector development
Detector Readout Signal TypeDigital Pulse: Arrival Time + Time-over-Threshold (ToT)N/AEncoded by leading edge and width of the pulse

The experimental approach combines high-purity material science with modular, high-precision electronics development.

  1. Material Selection: Use of mono-crystalline diamond (scCVD) selected specifically for negligible structural defects and chemical impurities to maximize Charge Collection Efficiency (CCE) crucial for MIP detection.
  2. Detector Configuration: Creation of diamond mosaic detectors or single plates with stripped read-out electrodes to enable high spatial resolution and beam position monitoring.
  3. Read-Out Platform Integration: Implementation of the existing, flexible TRB3 (Trigger and Readout Board) platform, featuring 260 channels of high-precision FPGA-TDCs.
  4. Front-End Adaptation: Utilization of the PADIWA discriminator board, with specialized adaptation of the analog input stage (amplifiers, variable impedance) to match the unique signal specifications of the diamond detector pre-amplifier.
  5. Signal Processing: Input signals are amplified, discriminated, and encoded digitally (arrival time and pulse width/ToT) via differential lines sent to the TRB3 for time measurements.
  6. Test Setup Optimization: Performance of XBEAM 2.1 simulations to optimize the magnet lattice (dipoles, quadrupoles) for the new E5 beam line, ensuring the electron beam is tightly focused and the beam envelope is minimized at the diamond detector test setup.

6CCVD is uniquely positioned to supply the advanced CVD diamond materials and customization services required to replicate and extend the highly specialized beam monitoring research documented herein.

To achieve the guaranteed radiation hardness, high CCE, and ultra-fast timing (< 50 ps) demanded by this application, Optical Grade Single Crystal Diamond (SCD) is the definitive material solution.

  • Material Specification: Our Optical Grade SCD ensures the ultra-low defect density and high purity necessary to maximize the drift velocity of electrons and holes, directly improving CCE for MIP detection.
  • BDD Option for Alternative Sensing: For alternative sensing modalities, such as radiation-resistant temperature or pressure sensors in extreme environments, we offer Boron-Doped Diamond (BDD) films with tunable conductivity.

The development of mosaic detectors (14 mm x 14 mm) and the use of stripped electrodes require specialized fabrication capabilities that 6CCVD provides in-house.

Custom ServiceApplication Relevance6CCVD Capability
Custom DimensionsMosaic assembly & beam profiling platesSCD wafers available up to 125 mm; precision laser cutting to specified dimensions (e.g., 14 mm x 14 mm pieces).
Thickness ControlOptimizing charge vs. timing for MIPsSCD and PCD plates available from 0.1 ”m up to 500 ”m, allowing fine-tuning of response time vs. collected charge.
Electrode DefinitionStripped read-out electrodes for position monitoringAdvanced lithography and etching services to define high-resolution electrode patterns.
Metalization StacksInterfacing diamond to pre-amplifiersIn-house deposition of custom metal stacks (e.g., Ti/Pt/Au, Ti/W) optimized for reliable ohmic contact and bonding to the front-end electronics (PADIWA).
Surface FinishMinimizing leakage current in high fieldsPolishing capabilities achieving Ra < 1 nm (SCD) ensure superior surface quality necessary for operation in high-voltage and high-radiation environments.

The successful integration relies on matching the analog front-end electronics to the precise signal characteristics of the SCD detector.

  • Material Consultation: 6CCVD’s in-house PhD material scientists specialize in detector applications. We assist research teams in selecting the optimal thickness and defect density (Nitrogen concentration) of SCD required for high-rate beam monitoring projects to ensure the system achieves the desired < 50 ps time resolution.
  • MIP Detection Optimization: We provide expert guidance on material preparation and surface treatments to maximize CCE in preparation for detecting Minimum-Ionizing Particles (MIPs) in high-energy accelerator environments.
  • Global Logistics: We offer secure global shipping (DDU default, DDP available) to ensure uninterrupted supply chain reliability for accelerator facilities worldwide.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

For future experiments with the HADES and CBM detectors at FAIR in Darmstadt, a radiation hard and fast beam detector is required. The beam detector has to perform precise T0 measurements (σ_{T0} < 50 ps) and should also offer beam monitoring capabilities. These tasks can be fulfilled by utilizing single-crystal Chemical Vapor Deposition (scCVD) diamond based detectors. For research and development of such detectors, a test set-up will be installed at the Superconducting Darmstadt Electron Linear Accelerator (S-DALINAC) of TU Darmstadt. A read-out system for a beam monitoring and diagnostics system is currently under development. It is based on the already well established TRB3 platform, which can provide FPGA based signal discriminators and high precision FPGA-TDCs with on-line monitoring capabilities. In this contribution the concept and the performance of a prototype beam monitoring system will be discussed. Furthermore the preparatory work, with particular focus on the beam-line simulations, for a multipurpose beam detector test set-up at the S-DALINAC will be addressed.