Speakers
Description
The HEXITEC$_{MHz}$ detector system is the latest generation of the STFC’s HEXITEC spectroscopic X-ray imaging detector systems. When coupled to Cd(Zn)Te sensor material, the original HEXITEC system delivers high-resolution X-ray spectroscopy (50 electrons RMS) per 250 μm pitch pixel for hard X-rays with energies 2 - 200 keV. However, a 9.1 kHz frame rate and the need to identify charge-sharing events limits its application to photon fluxes of ~10$^4$ ph s$^{-1}$ mm$^{-2}$. With many photon light sources undergoing major upgrades to diffraction-limited storage rings, these expected increases in flux have motivated the development of the next generation of the HEXITEC technology. This demand has also been driven by spectroscopic X-ray imaging techniques such as Hyperspectral X-ray Tomography, which require operation under a high incident X-ray flux for time-resolved measurements.
The HEXITEC$_{MHz}$ system is targeted at delivering the same high-resolution spectroscopy as the original ASIC whilst targeting higher photon fluxes. Whilst the ASIC maintains the same 250 μm pixel pitch, the new integrating Front End architecture, in-pixel digitisation and high-speed serialisers deliver a 1 MHz frame rate. This enables operation at fluxes of >10$^6$ ph s$^{-1}$ mm$^{-2}$ for spectroscopic X-ray imaging applications.
A 300 µm thick p-type Si HEXITEC$_{MHz}$ detector was characterised on the B16 Test Beamline at the Diamond Light Source and are the first measurements taken at a 1 MHz frame rate. At 10 keV and 15 keV the device displayed average FWHM of 656 eV and 682 eV respectively, with minimal changes in spectroscopic performance over ~8 h. Analysis of charge-sharing events show low charge loss and a linear energy-signal response. Higher-flux measurements illustrated the capability of HEXITEC$_{MHz}$ to operate as a photon-counting device, capable of measuring 30 × 10 keV photons in a single frame. Results from a high-flux CdZnTe device will also be shown.
| Your name | Ben Cline |
|---|---|
| Institute | UKRI STFC |
| Email address | ben.cline@stfc.ac.uk |
