A Configurable 64-Channel ASIC for Cherenkov Radiation Detection from Space

This work presents the development of a 64-channel application-specific integrated circuit (ASIC), implemented to detect the optical Cherenkov light from sub-orbital and orbital altitudes. These kinds of signals are generated by ultra-high energy cosmic rays (UHECRs) and cosmic neutrinos (CNs). The purpose of this front-end electronics is to provide a readout unit for a matrix of silicon photo-multipliers (SiPMs) to identify extensive air showers (EASs). Each event can be stored into a configurable array of 256 cells where the on-board digitization can take place with a programmable 12-bits Wilkinson analog-to-digital converter (ADC). The sampling, the conversion process, and the main digital logic of the ASIC run at 200 MHz, while the readout is managed by dedicated serializers operating at 400 MHz in double data rate (DDR). The chip is designed in a commercial 65 nm CMOS technology, ensuring a high configurability by selecting the partition of the channels, the resolution in the interval 8–12 bits, and the source of its trigger. The production and testing of the ASIC is planned for the forthcoming months

Methods to Retrieve the Cloud-Top Height in the Frame of the JEM-EUSO Mission

The Japanese Experiment Module-Extreme Universe Space Observatory (JEM-EUSO) telescope will measure ultrahigh-energy cosmic ray properties by detecting the UV fluorescence light generated in the interaction between cosmic rays and the atmosphere. Therefore, information on the state of clouds in the atmosphere is crucial for a proper interpretation of the data. For a real-time observation of the clouds in the telescope field of view, the JEM-EUSO will use an atmospheric monitoring system composed of a light detection and ranging and an infrared (IR) camera. In this paper, the focus is on the IR camera data. To retrieve the cloud-top height (CTH) from IR images, three different methods are considered here. The first one is based on bispectral stereo vision algorithms and requires two different views of the same scene in different spectral bands. For the second one, brightness temperatures provided by the IR camera are converted to effective cloud-top temperatures, from which the CTH is estimated using the vertical temperature profiles. A third method that uses the primary numerical weather prediction model output parameters, such as the cloud fraction, has also been considered to retrieve the CTH. This paper presents a first analysis, in which the heights retrieved by these three methodologies are compared with the heights given by the Moderate Resolution Imaging Spectroradiometer sensor installed on the polar satellite Terra. Since all these methods are suitable for the JEM-EUSO mission, they could be used in the future in a complementary way to improve the accuracy of the CTH retrieval