Prototype Testing of Energetic Charged Particle (ECP) Detector for the ESRA CubeSat Mission to GTO

The Experiment for Space Radiation Analysis (ESRA) is the first in a new series of demonstration and validation missions for the Los Alamos National Laboratory. This mission will utilize a 12U CubeSat platform and will be placed in a Geosynchronous Transfer Orbit (GTO) to make measurements of the dynamic charged particle populations in the Earth’s radiation belts. To date, there has never been an operational CubeSat in GTO. The Energetic Charged Particle (ECP) instrument on board the ESRA CubeSat is a particle telescope which aims to test and mature new technologies. The energy range of interest for the energetic charged particle sensor is from 100 keV to 1000 MeV for protons, and from 100 keV to 10 MeV for electrons. The instrument is comprised of five detection elements in a stacked configuration, surrounded with shielding to suppress spurious background events. We incorporate direct-to-digital readout electronics, with four channels served by a dedicated amplifier chain using Amptek A250 Charge Sensitive Amplifiers (CSA) and one channel processed by the Amptek A121 CSA with an integrated discriminator. Signals are processed onboard using a Lattice FPGA, and commanding and monitoring is performed using a SAMRH707 Cortex-M7 Microcontroller. Data is sent to the space vehicle for downlinking through a SpaceWire interface. Selectable readout modes allow us to control data collection rates for dynamic radiation environments. The instrument design minimizes size, weight, and power requirements while pursuing an ambitious scientific measurement capability. The ECP instrument has continued to mature, and a prototype has been built and tested prior to the ESRA mission Critical Design Review (CDR). Continued laboratory source calibrations as well as Field Programmable Gate Array (FPGA) software development have been proved out and validated for the ECP instrument. These were demonstrated via proton beam testing and calibrations performed at the Brookhaven National Laboratory (BNL) Tandem Van de Graaff. During these tests, energies between 5 – 28 MeV were impinged on the telescope with waveform, list mode, and binning data collected with less than 500 ns dispersion in coincident waveform pulses and less than 1% deviation of the linearity in energy calibration. These results, which will be presented, position ECP to be one of the first instruments on-orbit with such capabilities.