ECCS-EPSRC: A new generation of cost-effective, scalable and stable radiation detectors with ultrahigh detectivity

这是一所美国大学(布法罗)和两所英国大学(剑桥和牛津)的联合努力。有效地检测低剂量率辐射对于提高非侵入性诊断的安全性和能力至关重要，包括医学成像、核安全和产品检查。然而，目前的行业标准材料(即非晶态硒和碲化锌镉)对X射线的探测能力有限，以至于目前的医学标准X射线剂量率是一个很高的值，这增加了致癌的风险。为了提高医学成像的安全性，以及提高涉及电离辐射的广泛其他诊断的有效性，设计能够检测较低剂量率辐射并在运行中具有稳定性能的新材料是必不可少的。美国团队(布法罗大学)和英国团队(牛津大学和剑桥大学)的合作项目是开发新一代具有成本效益的铋基辐射探测器，能够探测到比当前商业标准低三个数量级的剂量率。该项目将直接解决设计高性能、运行稳定的辐射探测器的材料和可制造性方面的关键挑战。该项目更广泛的技术影响建立在与工业界和美国国家实验室的合作基础上。此外，研究计划与所有三所大学的教育和推广计划很好地结合在一起，包括：1)在国际研究环境中培训具有多学科研究技能的未来劳动力；2)通过教学在材料科学和工程课程中实施新型材料和设备的尖端研究；3)通过推广计划向更广泛的受众传播研究成果；以及4)增加当地社区中代表性不足的少数群体的多样性和广泛参与，有助于加强和扩大美国和英国未来的STEM劳动力，并提高社会对最先进的辐射探测技术发展的认识。最近，卤化铅钙钛矿单晶显著提高了辐射探测器的性能。然而，高铅(铅)含量超过了许多司法管辖区(包括美国和英国)设定的最高限值，而且这些材料中容易产生的离子导电性限制了可以施加的电场范围，从而限制了它们的运行稳定性。这项提议将解决目前X射线探测器面临的挑战，包括使用有毒元素、有限的性能、高制造成本和有限的电荷载体传输。我们的初步结果表明，BiOI由于其重元素、大迁移率寿命产物和高电阻率，有望成为下一代超高探测率辐射探测器的理想无毒替代铅基钙钛矿材料。为了将这项技术转化为工业，并对医学成像和核安全产生影响，我们将进一步1)通过成分工程将迁移率寿命产品提高到远高于6±2 x 10-2 cm2 V-1 S-1，2)在不影响性能的情况下将探测器的尺寸从目前的5 mm增加一个数量级，以及3)优化器件架构和成像性能。美国团队(水牛城大学)和英国团队(牛津大学和剑桥大学)的这项联合研究的总体目标是开发新一代经济高效、稳定和可放大的铋辐射探测器，能够探测到比当前商业标准低三个数量级的剂量率。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This is a joint effort between a U.S. University (Buffalo) and two U.K. Universities (Cambridge and Oxford).Effectively detecting low dose rates of radiation is critical for improving the safety and capability of non-invasive diagnostics, including medical imaging, nuclear security, and product inspection. However, current industry-standard materials (namely amorphous selenium and cadmium zinc telluride) have limited ability to detect X-rays, such that the current medical standard X-ray dose rate is a very high value, and this increases the risk of causing cancer. To improve the safety of medical imaging, as well as to improve the effectiveness of a wide range of other diagnostics involving ionizing radiation, it is essential to engineer new materials capable of detecting lower dose rates of radiation, with stable performance under operation. The collaborative project between the US team (University at Buffalo) and the UK team (University of Oxford and University of Cambridge) is to develop a new generation of cost-effective bismuth-based radiation detectors capable of detecting three orders of magnitude lower dose rates than the current commercial standard. The project will directly address the critical challenge of engineering the materials and the manufacturability for high-performing, operationally stable radiation detectors. The broader technological impacts of this project are built on collaborations with industry and a US national laboratory. Furthermore, the research program is well integrated with education and outreach programs at all three universities, including: 1) training the future workforce with multidisciplinary research skills in an international research environment; 2) implementing cutting-edge research in novel materials and devices in materials science and engineering curricula through teaching; 3) disseminating research findings to broader audiences through outreach programs; and 4) increasing diversity and broad participation of under-represented minority groups from local communities, contributing to strengthening and expanding the future STEM workforce in both US and UK and enhancing society awareness of development of state-of-the-art radiation detection technology.Significantly improved performance of radiation detectors has recently been achieved with lead-halide perovskite single crystals. However, the high lead (Pb) content exceeds the maximum limit set in many jurisdictions (including in the US and UK), and the facile ionic conductivity in these materials limits the range of electric fields that can be applied, thus limiting their operational stability. This proposal will address the challenges of current X-ray detectors, including the use of toxic elements, limited performance, high manufacturing costs, and limited charge-carrier transport. Our preliminary results have shown that BiOI can be the ideal non-toxic alternative to the Pb-based perovskites for next generation radiation detectors with ultrahigh detectivity because of its heavy elements, large mobility-lifetime products, and high resistivities. To transfer this technology to industry and to have an impact on medical imaging and nuclear security, we will further 1) improve the mobility-lifetime product to well above 6±2 x 10-2 cm2 V-1 s-1 through compositional engineering, 2) increase the size of the detectors by an order of magnitude (from 5 mm currently) without compromising on performance, and 3) optimize the device architecture and imaging performance. The overall aim of this joint research between US team (University at Buffalo) and the UK team (University of Oxford and University of Cambridge) is to develop a new generation of cost-effective, stable and up-scaled bismuth-based radiation detectors capable of detecting three orders of magnitude lower dose rates than the current commercial standard.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.