A naukri.com initiative
Physicsworld
4w
408
Image Credit: Physicsworld
Cascaded crystals move towards ultralow-dose X-ray imaging
- Researchers at the King Abdullah University of Science and Technology (KAUST) have developed a perovskite material that exhibits considerable stability, minimal ion migration and a high X-ray absorption cross-section – making it ideal for X-ray detection.
- A team created devices using lab-grown single crystals of MAPbBr3. They first selected four identical crystals to evaluate (SC1, SC2, SC3 and SC4), each 3 x 3 mm in area and approximately 2 mm thick. Measuring various optical and electrical properties revealed high consistency across the four samples.
- The researchers also measured the dark current for the four devices as the bias voltage changed from 0 to -10 V. They found that SC1 reached the highest dark current of 547 nA, while SC1–2, SC1–3 and SC1–4 showed progressively decreasing dark currents of 134, 90 and 50 nA, respectively
- The two-crystal SC1–2 represents the optimal balance of performance and stability.
- One key component required for low-dose X-ray imaging is a low detection threshold. The conventional single-crystal SC1 showed a detection limit of 590 nGy/s under a 2 V bias. SC1–2 decreased this limit to 100 nGy/s
- Spatial resolution is another important consideration. To assess this, the researchers estimated the modulation transfer function (the level of original contrast maintained by the detector) for each of the four devices. They found that SC1–2 exhibited the best spatial resolution of 8.5 line pairs/mm.
- In conclusion, the cascade-engineered configuration represents a significant shift in low-dose X-ray detection, with potential to advance applications that require minimal radiation exposure combined with excellent image quality.
- The researchers are now investigating the application of the cascade structure in other perovskite single crystals, such as FAPbI3 and MAPbI3, with the goal of reducing their detection limits.
Read Full Article
24 Likes
For uninterrupted reading, download the app