Pix.PAN is a compact cylindrical magnetic spectrometer, intended to provide excellent high energy particle measurements under high rate and hostile operating conditions in space. Its principal design is composed of two Halbach-array magnetic sectors and six Timepix4-based tracking layers; the latest hybrid silicon pixel detector readout ASIC designed. Due to Pix.PAN’s compact and relatively simple design, it has the potential to be used for space missions exploring with measurements of unprecedented precision, high energy particles in radiation belts and the heliophere (solar energetic particles, anomalous and galactic cosmic rays). In this white paper, we discuss the design and expected performance of Pix.PAN for COMPASS (Comprehensive Observations of Magnetospheric Particle Acceleration, Sources, and Sinks), a mission concept submitted to NASA’s Call “B.16 Heliophysics Mission Concept Studies (HMCS)” in 2021 that targets the extreme high energy particle environment of Jupiter’s inner radiation belts. We also discuss PixPAN’s operational conditions and interface requirements. The conceptual design shows that is possible to achieve an energy resolution of<12% for electrons in the range of 10 MeV-1 GeV and<35% for protons between \(\sim \)200 MeV to a few GeV. Due to the timestamp precision of Timepix4, a time resolution (on an instrument level) of about 100 ps can be achieved for time-of-flight measurements. In the most intense radiation environments of the COMPASS mission, Pix.PAN is expected to have a maximum hit rate of 44\(\frac{\text {MHz}}{\text {cm}^2}\) which is below the design limit of 360\(\frac{\text {MHz}}{\text {cm}^2}\) of Timepix4. Finally, a sensor design is proposed which allows the instrument to operate with a power budget of 20W without the loss of scientific performance.

Pix.PAN 是一款紧凑型圆柱形磁谱仪，旨在在太空中的高速率和恶劣操作条件下提供出色的高能粒子测量。其主要设计由两个 Halbach 阵列磁扇区和六个基于 Timepix4 的跟踪层组成；最新设计的混合硅像素检测器读出 ASIC。由于 Pix.PAN 的紧凑且相对简单的设计，它有可能用于太空任务，以前所未有的精度测量辐射带和日光层中的高能粒子（太阳高能粒子、异常和银河宇宙射线）。在本白皮书中，我们讨论了 COMPASS（磁层粒子加速、源和汇的综合观测）的Pix.PAN 的设计和预期性能，这是一个提交给 NASA 号召“B.16”的任务概念2021 年的“太阳物理学任务概念研究 (HMCS)”，目标是木星内部辐射带的极端高能粒子环境。我们还讨论了 PixPAN 的运行条件和接口要求。概念设计表明，对于 10 MeV-1 GeV 范围内的电子，可以实现 <12% 的能量分辨率；对于 200 MeV 到几 GeV 范围内的质子，可以实现 <35% 的能量分辨率。由于 Timepix4 的时间戳精度，飞行时间测量可以实现约 100 ps 的时间分辨率（仪器级别）。在 COMPASS 任务最强烈的辐射环境中，Pix.PAN 预计最大命中率为 44 \(\frac{\text {MHz}}{\text {cm}^2}\)，低于Timepix4 的设计极限为 360 \(\frac{\text {MHz}}{\text {cm}^2}\)。最后，提出了一种传感器设计，允许仪器以 20W 的功率预算运行，而不会损失科学性能。