A compact and portable X-ray beam position monitor using Medipix3

Abstract

The present work reports on the design and implementation of a novel portable Xray beam diagnostics (XBPM) device. The device is transparent to the X-ray beam and provides real-time measurements of beam position, intensity, and size. The measurement principle is based on a pinhole camera which records scattered radiation from a Kapton foil which is placed in the beam path. The use of hybrid detectors (Medipix3) that feature a virtually noiseless readout system with capability of single photon detection and energy resolving power enables the diagnostics with a better resolution and higher sensitivity compared to the use of traditional indirect X-ray detection schemes.We describe the detailed system design, which consists of a vacuum compatible focal plane sensor array, a sensor conditioning and readout board and a heterogeneous data processing unit, which also acts as a network server that handles network communications with clients. The readout protocol for the Medipix3 sensor is implemented using field programmable gate array (FPGA) logic resulting in a versatile and scalable system that is capable of performing advanced functions such as data compression techniques and feature extraction. For the system performance measurements, we equipped the instrument with a single Medipix3 die, bump bonded to a Si sensor, rather than four for which it was designed. Without data compression, it is capable of acquiring magnified images and profiles of synchrotron X-ray beams at a transfer rate through Ethernet of 27 frames/s for one Medipix3 die.

Performance of the Lancelot Beam Position Monitor at the Diamond Light Source

“…The Medipix3RX silicon sensor array is operated in single pixel mode with a 6-bit counter depth. Previous tests on a Lancelot module with a Medipix3 sensor at the B16 beamline at Diamond Light Source are reported in [9].…”

X-ray position-sensitive duo-lateral diamond detectors at SOLEIL

“…In order to precisely monitor the intensity and adjust the position of the X-ray beams, such beamlines need a fast X-ray diagnostic inserted permanently into the beam (with low absorption and radiation hardness). Many different kinds of in-beam transparent position monitors have been used in the past: microwire devices (Heald, 1986), gaseous detectors (Schildkamp & Pradervand, 1995), indirect fluorescent or scattered X-ray detection from thin foils with PIN-diodes (Alkire et al, 2000) or pixelated detectors (Rico-Alvarez et al, 2014), as well as thin solid-state devices developed on silicon (Fuchs et al, 2007) or polycrystalline diamond (Bergonzo et al, 1999). In this paper, a new type of diamond X-ray beam position monitor (XBPM) is presented: the device is based on an electronic-grade singlecrystal chemical-vapour-deposition (CVD) diamond material (Morse et al, 2010) processed on a duo-lateral positionsensitive detector (PSD) with diamond-like carbon (DLC) resistive coating (Pomorski et al, 2009).…”