Part 3: The Value of Ensuring Confidence in Beam Stabilization

Part 1 of this series on Sydor’s x-ray beam monitors provided an overview of diamond-based detectors.

Part 2 highlighted the capabilities of Sydor’s single-channel devices for use as intensity and timing monitors.

Part 3 will discuss the importance of beam stabilization and immediate impact reliable position monitors can have on beamline operations.

How to Make the Most Effective Use of Costly Beam Time

As we all know, beam time is expensive. Performance of proprietary research at synchrotrons costs thousands of dollars each day. Depending on each individual facility’s policies, fees may apply for additional scientific & beamline staffing. Combined with experiment supplies, travel cost, and preparation, expenses add up quickly. Example rates for FY23 are shown below, taken from facility websites or through communication with each facility’s Users Office:

Beam time is a scarce resource, and light source upgrades currently underway or planned in the coming years will exacerbate this. Between financial cost and time-investment, any allotted beam time should be spent performing the actual experiments, rather than being consumed adjusting optical components and searching for the beam.

To optimize alignment procedures and reduce the risk of time lost during experiments, a reliable beam position monitoring method should be used. Paired electronic controls with programmable PID functionality, outputs can be utilized to automate alignment procedures and monitor beam conditions to simplify troubleshooting. These correction methods are only as reliable as the beam position data.

For decades, beam monitoring solutions such as photodiodes, ion monitors, blade monitors, and foil monitors have been in use. Each method brings its own limitations that can contribute to delays and downtime spent installing replacements or undergoing repairs. Ion chambers and photodiodes are susceptible to saturation and foil monitors often fail due to radiation exposure. Blade monitors are susceptible to radiation and do not exhibit good sensitivity at lower energies. Time lost due to these limitations, is money lost or data not collected.

Flange-Mounted Beam Monitor

Stage-Mounted Beam Monitor

Sydor’s diamond-based position monitors meet the requirements for a reliable beam monitoring device: radiation hard, robust for use with the fluxes of modern upgraded facilities, precise position resolution, low absorption of the beam, and compact form-factor. These beam monitors are deployed across the globe, with many in use for a decade. Each monitor can be customized to account for beamline configuration, enabling them to be continuously run in-situ without impacting the beam properties.

Why Diamond is a Good Sensor Material for Beam Monitoring Devices

Sydor’s reliable and small footprint beam monitoring tools offer superior performance to other methods due to the properties of the electronic-grade single-crystal diamonds they are built with. Diamond is a radiation hardened material with good resistance to mechanical stresses. This has allowed many monitors to be in continuous operation for over a decade since their initial deployment. Diamond-based monitors may have a higher up-front cost than other monitoring methods, but they are a long lifetime product.

The high-quality diamonds used in Sydor monitors have very low x-ray absorption, with transmission exceeding 90% above 5 keV. Monitors built with electronic-grade single-crystal diamonds have demonstrated linearity in response over eleven orders of magnitude from 100 pW to 10 W. Competitive monitors built using polycrystalline diamonds have less linearity and demonstrate variability in performance. By manufacturing monitors with only the highest quality single-crystal diamonds, Sydor’s monitors can be operated in-situ over a wide range of x-ray energies, maintaining its linear response and without concerns of saturation as seen with other monitoring methods.

Dark current is a standard measurement for each of Sydor’s monitors, consistently <0.1 pA which is orders of magnitude less than competitive diamond-based monitors on the market. This low dark noise enables superior position resolution down to 0.1% of the beam’s diameter, down to 25 nm.

How Sydor’s Diamond-Based Beam Monitors Work

Sydor’s position monitors are built sandwiching a diamond between metallized pads-with four metallized quadrants on the front side of the monitor. As x-rays are absorbed by the diamond, charge is generated and a voltage is applied to the diamond to collect the charge. The beam’s intensity is calculated by adding the net charges and the beam position is determined by comparing the net charge within each quadrant. Calibration of the electrometer and position monitor in the factory ensure the beam’s positioning is maintained within a very small window.

With Sydor’s beam position monitors and T4U Electrometer with PID, the beam can be tracked in real time. An example of Sydor’s GUI is shown to the left, demonstrating readings from each individual channel as well as the X & Y positions over time.

Readout Electronics with PID Simplify Alignment Procedures

Once initial beam alignment is complete, maintaining that alignment is the next critical step to consistent experiments. The T4U Electrometer with PID can provide analog outputs at 10 Hz to external control equipment that enables alignment. Beam motion can automatically be suppressed and deviation from the desired location can be corrected for. This automated feedback is a key benefit of the beam position monitors paired with the T4U Electrometer with PID. An example of the stabilization capabilities of the system is shown to the right, demonstrating a nearly 4x improvement when feedback is enabled.

Built-to-Order Monitoring Devices

Sydor’s x-ray position monitors are all built-to-order and can be designed with housings customized for each customer’s preferences. In the decade that these monitors have been sold by Sydor, a handful of commonly requested designs have become a part of our standard offerings. These can be provided as standalone devices, or provided with additional components such as stages, bellows, and vacuum chambers. Seen here are two flange-mounted variations and a stage-mountable unit.

Below is a sampling of the most common offerings:

Monitor Format	“In-Air” Monitor	Stage-Mounted Monitor	Flange-Mounted Monitor
Housing
Other Available Flanges	N/A	N/A	DN25 CF, DN160 CF, KF25, KF40, & more
Read out	4- channel
Detection area	3.1 mm x 3.1 mm with 20 µm streets
Acquisition rate	kHz
Potential Applications	Position monitoring Flux Monitoring Feedback*

*when used with Sydor’s T4U Electrometer with PID

To read more about the latest advancements in diamond-based detectors and beam diagnostics, please look for the next installment in this article series titled “Part 4: “Simplifying Beam Diagnostics Collection with the Transparent X-ray Camera – Time-Saving In-Situ Collection of Beam Profile, Position, and Flux” in about 2 weeks.

For additional information please visit our X-ray Beam Monitors Page or contact us for a technical consultation with one of our technology experts.