HERMES Project: Pioneering High-Energy Observations

The High Energy Rapid Modular Ensemble of Satellites (HERMES) project is a group of six small satellites, called CubeSats, that aim to observe fast-changing high-energy events in space, such as Gamma Ray Bursts (GRBs). These events are of great interest to scientists studying the universe, as they provide information about incredible cosmic phenomena. HERMES will be unique because it will use a special type of detector called the siswich detector, which can measure a wide range of energy, from 2 keV to 2 MeV.

#Why Calibration is Important

In order for the HERMES satellites to accurately measure the energy of the incoming signals, they need to be properly calibrated. Calibration is like tuning a musical instrument; it ensures that the measurements taken by the Detectors are correct. However, the siswich detector is complicated, and there is no standard method for calibrating it. Therefore, a specific calibration pipeline has been developed to handle the unique features of this detector.

#What is the Calibration Pipeline?

The calibration pipeline is a computer program designed to process the raw Data from the HERMES detectors. It focuses on making sure that the energy readings from the detectors are accurate and useful. The program minimizes the amount of handling needed by users and includes automatic identification of the calibration lines, which are key points used for checking accuracy.

#Overview of the HERMES System

Each HERMES satellite includes a miniaturized instrument equipped with a hybrid Silicon Drift Detector (SDD) and a special crystal that helps in detecting both X-rays and gamma-rays. The aim is to monitor the sky for high-energy events and provide better localization of these events. This is especially important for understanding things like Gamma Ray Bursts and the light signals that come from merging black holes.

#The Structure of the HERMES Detectors

The HERMES detectors consist of multiple sections that work independently, allowing them to read out data from 120 different channels. Each channel detects incoming radiation, and the data must be properly processed to distinguish between X-ray and gamma-ray signals. The HERMES detectors use a solid-state technology, which means they work better and can provide more accurate measurements compared to older technologies.

#Data Format and Collection

The HERMES satellites collect data continuously. When a significant event is detected, the satellites send out data packets containing the information about what was detected, the time of detection, and more. This data is organized in a way that allows scientists to analyze it effectively once it reaches the ground.

#The Role of Software in Calibration

The calibration pipeline is implemented using Python, a popular programming language. The program begins by reading a specific type of data file that contains the raw measurements from the detectors. It then filters out data that is the result of electronic noise, which can interfere with the accuracy of the measurements. The software organizes the clean data into categories based on the type of event detected.

#Steps in the Calibration Process

1. Data Filtering: The pipeline first cleans the data by removing unwanted signals caused by electronic noise.

2. Tagging Events: Each event is tagged based on whether it is an X-mode or S-mode event. This is important because the calibration process differs depending on the type of event.

3. Building Spectra: For X-mode events, the software creates spectra by plotting the amplitude of signals for each channel. This helps in identifying where the energy peaks occur.

4. Peak Detection: An algorithm looks for peaks in the spectra, which correspond to known calibration lines.

5. Calibration Function: Once peaks are identified, the software computes the necessary calibration functions based on known energy values of calibration lines.

#User Interaction with the Pipeline

While the automation in the pipeline is designed to reduce the need for manual intervention, users still have the option to interact with the software if necessary. After the automatic calibration is completed, the user can make adjustments and even re-run the calibration if required.

#The Importance of Data Products

The calibration pipeline generates several important data products. These include:

• Results Tables: Detailed reports that provide information about the calibration process.
• Data Plots: Visual representations of the data, which help scientists quickly check performances.
• Calibrated Event Lists: Organized lists of detected events, showing their energy measurements.

These products are essential for scientists to analyze the performance of the detectors and understand any issues that may arise during the operation.

#Analyzing the Data

After calibration, the data is analyzed to ensure that the detectors are functioning as expected. This is where scientists can check for any issues, such as channels that are not responding properly or producing inaccurate measurements. The diagnostic plots provide a visual representation of the performance, making it easier to identify any potential problems.

#Conclusion

The HERMES project represents a significant advancement in the field of high-energy astrophysics. The calibration pipeline is a crucial component that ensures accurate measurements from the siswich detectors. By automating much of the calibration process, scientists can focus on analyzing the data and making new discoveries about our universe. With the HERMES satellites set to launch soon, the scientific community is eager to see the insights they will provide into the mysteries of high-energy cosmic events.