Silicon nanochannel plates (NCPs) are efficient positron to positronium converters and are employed as sources of abundant cold positronium. Characterization of the emitted positronium energy spectrum is crucial to assess the NCP performance and support their further optimization. We present here a Time-of-Flight (ToF) system optimized to measure the energy spectrum of positronium produced by NCP converters held at cryogenic temperatures. The ToF-apparatus was tested by implanting 7 keV positrons into NCPs at room temperature before performing ToF experiments using positron implantation energies of 7 and 11 keV into NCPs held at 20 K. At these conditions we succeeded in determining the energy spectrum of the positronium escaping from the nanochannels into the vacuum down to an energy of 10 meV.

硅纳米通道板（NCP）是高效的正电子到正电子的转换器，并用作大量冷正电子的来源。发射的正电子能谱的表征对于评估NCP性能并支持其进一步优化至关重要。我们在此介绍一种飞行时间（ToF）系统，该系统经过优化，可测量保持在低温下的NCP转换器产生的produced的能谱。通过 在室温下将7 keV正电子注入NCP中来测试ToF装置，然后使用 保持在20  K的NCP中的正电子注入能量分别为7和11 keV进行ToF实验。在这些条件下，我们成功地确定了逃逸的正电子能谱从纳米通道到真空到10的能量 meV。