Method for visualizing detailed profiles of synchrotron X-ray beams using diamond-thin films and silicon drift detectors

At a Glance

Metadata	Details
Publication Date	2025-04-22
Journal	Journal of Synchrotron Radiation
Authors	Togo Kudo, Shinji Suzuki, Mutsumi Sano, Toshiro Itoga, Hiroyasu Masunaga
Institutions	Japan Synchrotron Radiation Research Institute
Analysis	Full AI Review Included

Technical Documentation & Analysis: Diamond Films for Synchrotron Beam Monitoring

This document analyzes the research paper “Method for visualizing detailed profiles of synchrotron X-ray beams using diamond-thin films and silicon drift detectors” (Kudo et al., J. Synchrotron Rad. 2025) and outlines how 6CCVD’s advanced MPCVD diamond materials and customization capabilities directly support and enable this critical synchrotron diagnostics technology.

Executive Summary

The research successfully demonstrates a high-precision, energy-resolved method for visualizing synchrotron undulator beam profiles using a thin Single-Crystal Diamond (SCD) film as a scatterer.

Core Value Proposition: Accurate determination of the true X-ray beam center by effectively eliminating contamination from nearby bending magnet radiation.
Material Requirement: A high-purity, thin (70 µm) SCD film was essential for scattering the pink X-ray beam while minimizing heat load and absorption.
Technical Achievement: Achieved high energy resolution (ΔE = 140 eV FWHM) using a Silicon Drift Detector (SDD) coupled with pinhole imaging.
Spatial Resolution: Demonstrated a spatial resolution limit of 50 µm, enabling detailed visualization of beam splitting and convergence patterns across various energy levels.
Methodology: Two distinct scanning methods (SDD scan for high spatial resolution and FES scan for wide-field visualization) were validated against SPECTRA simulations.
6CCVD Relevance: 6CCVD specializes in producing the required high-purity SCD films with precise thickness control (0.1 µm to 500 µm) and custom metalization necessary for robust mounting in high-vacuum synchrotron environments.

Technical Specifications

The following hard data points were extracted from the experimental setup and results:

Parameter	Value	Unit	Context
Diamond Material	Single Crystal Diamond (SCD)	N/A	Used as the X-ray scatterer
Diamond Thickness	70	µm	Critical dimension for scattering efficiency and heat load
SDD Energy Resolution (ΔE)	140	eV (FWHM)	Resolution used to filter bending magnet contamination
Spatial Resolution Limit	50	µm	Established by Pinhole 1 diameter
FES Aperture (High Resolution Scan)	1.5 x 1.5	mm	Fixed aperture during SDD 2D scan
FES Aperture (Wide Field Scan)	0.4 x 0.4	mm	Scanned aperture during FES 2D scan
Undulator Gap (SDD Scan)	26	mm	First harmonic peak at 17.3 keV
Undulator Gap (FES Scan)	14.8	mm	First harmonic peak at 10 keV
Beam Center FWHM (Vertical, 16.9 keV)	~500	µm	Measured beam size, significantly smaller than FES aperture
Contamination Reduction	4 orders of magnitude	N/A	Reduction of bending magnet flux near beam center

Key Methodologies

The experiment utilized a semi-nondestructive approach combining high-purity diamond scattering films with energy-resolved detection.

Diamond Scatterer Integration: A 70 µm thick Single-Crystal Diamond (SCD) film was installed in a vacuum chamber (35.407 m from the light source) to scatter the pink synchrotron beam.
Beam Definition: A Front-End Slit (FES) was used upstream of the monochromator to define the beam aperture (e.g., 1.5 mm x 1.5 mm for high-resolution scans).
Pinhole Camera Setup: Forward-scattered X-rays were extracted through a Be window and imaged using a pinhole camera system (Pinhole 1: 50 µm diameter; Pinhole 2: 200 µm diameter).
High-Spatial Resolution Measurement (SDD Scan): The SDD detector assembly (with Pinhole 2) was scanned in 2D (200 µm increments) across the beam profile to achieve high spatial detail (50 µm limit).
Wide-Field Measurement (FES Scan): The FES aperture was reduced (0.4 mm x 0.4 mm) and scanned in 2D (0.1 mm pitch) across a 5 mm range, while the SDD remained fixed, enabling visualization of the full pre-slit profile (up to 4 mm aperture).
Energy Filtering: The high energy resolution of the SDD (ΔE = 140 eV) was crucial for analyzing energy-resolved intensity maps and isolating the undulator radiation from lower-energy bending magnet contamination.

6CCVD Solutions & Capabilities

This research highlights the critical role of high-quality, precisely manufactured diamond films in advanced synchrotron diagnostics. 6CCVD is uniquely positioned to supply the materials and engineering support required to replicate and advance this technology.

Applicable Materials

The success of this method relies entirely on the purity, crystallinity, and precise thickness of the diamond scatterer.

Research Requirement	6CCVD Solution	Material Specification
High Purity Scatterer	Optical Grade Single Crystal Diamond (SCD)	High-purity MPCVD SCD ensures minimal absorption and low background noise, crucial for accurate energy-resolved measurements.
Precise Thickness (70 µm)	Custom SCD Wafers	6CCVD offers SCD thickness control from 0.1 µm up to 500 µm, allowing researchers to optimize the scattering cross-section versus heat load for specific beamlines.
High Heat Load Management	Thermal Grade SCD	For future high-power applications, 6CCVD can supply SCD with thermal conductivity > 2000 W/mK, essential for managing heat load on the optics system (a limitation noted in the paper).

Customization Potential

The experimental setup requires highly specific component dimensions and integration features, which 6CCVD provides as standard services.

Custom Dimensions: While the paper used a specific size, 6CCVD can supply SCD plates and wafers up to 125 mm (PCD) and custom-cut SCD pieces to fit any vacuum chamber mount or FES geometry.
Precision Polishing: To maintain beam quality and minimize surface scattering artifacts, 6CCVD guarantees ultra-smooth surfaces. We offer polishing down to Ra < 1 nm for SCD, ensuring the highest optical quality for beam monitoring applications.
Integrated Metalization Services: The diamond film must be robustly mounted for thermal sinking and structural integrity in the UHV environment. 6CCVD offers in-house metalization capabilities, including Ti/Pt/Au, W, Cu, and Pd coatings, optimized for brazing or clamping into water-cooled mounts, directly addressing the heat load limitations discussed in the paper.

Engineering Support

The challenges noted in the paper—specifically optimizing thickness for heat load and achieving faster measurement times—require expert material consultation.

Application Expertise: 6CCVD’s in-house PhD team specializes in material selection for high-flux X-ray beam diagnostics and beam position monitors (XBPMs). We can assist researchers in optimizing diamond thickness and purity for similar Synchrotron Beam Profile Monitoring projects.
Advanced Detector Integration: We provide consultation on integrating diamond films with advanced detectors, including multi-element SDDs, to reduce measurement time from hours to seconds, as suggested for future work in the paper.

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

View Original Abstract

Contamination from nearby bending magnet radiation hinders precise and accurate determination of the true beam center of undulator radiation. To solve this problem, a semi-nondestructive method was developed to visualize the detailed profile of a synchrotron radiation beam by using a thin diamond film as a scatterer. As the beam passed through the diamond film, scattered X-rays were imaged using a pinhole camera and measured with a two-dimensional silicon drift detector (SDD) scan. With this configuration, the beam center was accurately determined by visualizing the radiation pattern distribution for each energy level of a pink X-ray beam within an aperture size of 1.5 mm × 1.5 mm, shaped by a front-end slit (FES) positioned upstream of the monochromator. Additionally, by scanning the FES in two dimensions with a reduced aperture of 0.4 mm × 0.4 mm, energy-resolved images were successfully obtained using the SDD at a fixed position. These images revealed the profile of undulator radiation over a broad area (with an aperture extending up to 4 mm) in a pre-slit positioned upstream of the FES, demonstrating good alignment with SPECTRA calculations. This method effectively eliminates contamination from nearby bending magnet radiation, a significant issue in previous approaches, enabling a direct and highly accurate determination of the true beam center.

Tech Support

Original Source

DOI: https://doi.org/10.1107/s1600577525002838