Development and Exploitation of a Novel Multi-Purpose Particle Detector for Radiation Monitoring in Space Exploration

辐射监测和防护是医学物理学中的关键课题，与载人空间探索特别相关。目前的辐射探测技术缺乏确保宇航员在地球保护性大气层以外的旅行中安全的关键能力，例如前往月球或火星。准确了解宇宙辐射的组成对于了解辐射的生物有效性和开发更好的屏蔽技术非常重要。我们正在开发一种新的探测器概念，称为多用途主动目标粒子望远镜(MAPT)，它结合了目前使用的系统的许多优点，并克服了它们的许多局限性。我们使用最先进的光电传感器和闪烁体构建了一种紧凑、轻便、低功耗的设备，可以测量单个粒子的能量和方向，并具有准全向接受能力。凭借其新颖的探测器概念，MAPT在能量低于1GeV/n的情况下可以比传统的粒子望远镜更好地识别粒子种类。虽然不如复杂的光谱仪强大，但它的建造和操作将大大简化。这既有科学上的优势，也有操作上的优势。我们计划与美国的合作伙伴合作，在国际空间站(ISS)部署一项技术演示实验。如果成功证明，MAPT可以取代目前国际空间站上使用的大多数固定式辐射探测器。它的设计还允许在整个空间站进行更灵活的部署。未来的深空任务可能会配备稍加修改的MAPT版本，以满足每一次任务的要求。除了将该仪器的能力与现有设备进行比较外，该实验还将提供迄今无法获得的数据。我们计划实时测量宇宙辐射的组成、能量和角光谱，以及特定粒子种类的通量分布。MAPT的独特能力还使我们能够对带电的初级辐射和(带电和未带电的)次级辐射进行相关测量，例如，在宇宙射线与航天器的相互作用中产生的次级辐射。可获得的能量范围从25 MeV/n到大约1GeV/n是粒子物种特有的。我们获得的数据可以补充，并与实验室对不同辐射粒子在细胞水平上的影响的测量相结合，有助于进一步了解高电离辐射，如高能原子核对宇航员的影响。这一领域的巨大不确定性是导致任务持续时间受限的主要因素。MAPT概念还提供了许多允许在其他领域应用的特征。其中包括通过精确测定比能量损失在与放射治疗相关的能量上的出色能量分辨率，以及在其他探测器概念达不到的极低能量下识别反粒子。

Radiation monitoring and protection are key topics in medical physics and are of particular relevance to manned space exploration. Current radiation detection technologies lack capabilities that are crucial to ensure astronaut safety on journeys beyond Earth’s protective atmosphere, such as to the moon or Mars. A precise knowledge of the composition of cosmic radiation is important to understand the biological effectiveness of radiation and to develop better shielding technologies.We are developing a new detector concept, called the Multipurpose Active-target Particle Telescope (MAPT), that combines many of the advantages of currently used systems and overcomes many of their limitations. We use state-of-the-art photosensors and scintillators to construct a compact, lightweight device with low power consumption that can measure energy and direction for individual particles with a quasi-omnidirectional acceptance. With its novel detector concept, MAPT can better identify particle species than traditional particle telescopes at energies below 1 GeV/n. While being less powerful than a complex spectrometer, it would be significantly simpler to construct and operate. This has both scientific and operational advantages.We plan to deploy a technology demonstration experiment to the International Space Station (ISS) in cooperation with U.S.-based partners. If successfully proven, MAPT could replace most stationary radiation detectors that are currently in use on the ISS. Its design also allows a more flexible deployment throughout the station. Future deep-space missions could be equipped with slightly modified versions of MAPT, accounting for each mission’s requirements.Besides comparing the instrument’s capabilities to existing devices, the experiment shall provide data that is so far unavailable. We plan to measure the composition, the energy and angular spectra, and particle species-specific flux profiles of cosmic radiation in real time. MAPT’s unique capabilities also allow us to take correlated measurements of charged primary radiation and (charged and uncharged) secondary radiation that is for example created in interactions of cosmic rays with the spacecraft. The accessible energy range of 25 MeV/n to about 1 GeV/n is particle species-specific.Data obtained by us could be supplemented and combined with laboratory measurements of the impact of different radiation particles at the cellular level, helping to further the understanding of the effects of highly-ionizing radiation, e.g. high-energy atomic nuclei, on astronauts. Large uncertainties in this area are the main factor driving limitations on mission durations.The MAPT concept also provides many features that allowing applications in other fields. Among these are excellent energy resolution at energies relevant to radiation therapy through precise determination of the specific energy loss and the identification of antiparticles at very low energies out of reach for other detector concepts.