Innovative ams X-ray detector chips usher in a new era of low-cost CT
China, December 19, 2019 – ams AG (SIX: AMS), a leading global provider of high-performance sensor solutions, announced that with its latest integrated X-ray detector chip — AS5950, ams will further reduce the cost of computed tomography (CT) equipment. Leveraging ams’ expertise in sensor design and packaging, the AS5950 integrated X-ray detector chip enables enhanced CT detector performance, more detailed images and lower system cost.
The AS5950 CMOS device integrates a high-sensitivity photodiode array and a 64-channel analog-to-digital converter on the same chip. The AS5950 single chip is easier to install into CT detector modules. Currently, CT scanner manufacturers need to mount a discrete photodiode array on a complex PCB and connect it to a discrete readout chip with long traces. Replacing complex PCB assemblies in 8- and 16-layer CT scanners with a single AS5950 chip greatly reduces image noise and, more importantly, material and production costs for manufacturers.
Jose Vinau, Marketing Director for the Medical and Professional Sensors business line at ams, said: “ams hopes to further reduce the cost of CT scanners and make them more widely available around the world. The introduction of the AS5950 and its modules will simplify X-ray Assembly and production of detectors.”
Technological innovation drives market development
According to ams estimates, the medical imaging market for 8- and 16-slice CT scanners will grow at a CAGR of 10-15%.
ams integrates a photodiode array and an analog-to-digital converter in a single chip. For medical device buyers, this innovation will reduce the cost of 8-slice and 16-slice CT scanners, making them more ubiquitous, while also helping to drive market demand and accelerate market development.
The AS5950 also optimizes the pixel size to 0.98×0.98 mm. With reasonable lead times, ams can also provide custom pixel sizes according to OEM’s special requirements.
The sensor can be mounted directly on the substrate by using the soldering method used to produce CT modules. The CT module reference design (AS5950M) developed by ams and partners simplifies integration into a complete CT detector. This double-sided splicable module can mount 2 x 2 AS5950s on one base plate to create a 32 x 16 mm sensing area, or 2 x 4 AS5950s to create a 32 x 32 mm sensing area .
Better medical image computing performance
Optimized wafer-level interconnect between the photodiode array and readout circuitry further reduces noise compared to board-level traces in discrete photodiode/ADC assemblies, so the AS5950’s integrated architecture improves imaging performance . the result is:
· Improved image quality. The noise in high-resolution mode is typically only 0.20 fC for a full-scale charge of 455 pC. ADC linearity of ±300 ppm and composite linearity of ±600 ppm (including photodiode) help improve image fidelity.
· Reduced self-heating effects. Power consumption is extremely low, typically 0.65 mW per channel, allowing manufacturers to adopt low-cost air cooling for CT scanners. An integrated temperature sensor monitors the junction temperature.
AS5950 can also perform quick integration, only 200 µs to support the higher rotational speed of the scanner. Digital data reading can be done through the SPI interface, which can also be set as follows:
· Active sensing area. Since the chip adopts the concept of three-sided splicing, the Z dimension of the detector module is 16 mm or 32 mm.
· Pixel resolution. The adaptive array allows you to operate the device in two modes: a high-resolution mode with a standard pixel size of 0.98 x 0.98 mm, or a larger Z-shaped coverage mode that connects two pixels into a total size of 1.96 x 0.98 mm pixel size.
·Full scale range. Depending on the radiation dose used, the maximum photodiode current can be configured from 200 nA to 600 nA, covering three full-scale ranges.
Samples of the AS5950 sensor IC and the AS5950M reference module are available now. We also offer evaluation kits for interfacing sensors and module reference designs. In addition, an FPGA board and software are provided to demonstrate all relevant performance parameters.