gamma-bits

Python script to extract data from ORTEC MAESTRO List Mode files (.Lis). Specifically tailored to operation of the ORTEC IDM-200-V, which shares file formats with ORTEC DSpec Pro and DSpec 50/502 instruments.

Usage from command line:

python process_listmode.py inputFile.Lis outFileName.csv

Contents:

• process_listmode.py: Python script to be run on the list mode (binary) file.
• sample_data/: folder with sample input list mode file and corresponding output .csv file.

Data structure explanation:

The .Lis file encoding provided by MAESTRO is outlined in the hardware manual that accompanies each device, as well as here: https://www.ortec-online.com/-/media/ametekortec/manuals/l/list-mode-file-formats.pdf?la=en&revision=0b78b32a-9ee7-4243-b4ac-a8adb886381d

The file is a byte-stream of data that is parsed into a 256-byte header and subsequent data. This script is written for the ORTEC IDM-200-V (and other PRO List formats), which has data consisting of a string of 32-bit words. Words are encoded by type. The currently supported data that are parsed to the output .csv file are

• ADC value
• Time stamp (combining the coarse and fine time stamps provided by the device)

(Added 05/08/2024) Now additionally parses, but does not save to the .csv:

• each Windows time stamp, generated by the computer upon data request from the computer to the spectrometer
• each Hardware time stamp, generated by the spectrometer upon data request delivery

The additional file outFileName_metadata.txt provides:

• the first Windows time stamp of data request
• mean, standard deviation, and spread (min and max value) of these delays (Hardware-Windows), which can be used to characterize the response time of the spectrometer.

Chunk processing for large files:

(Added 02/24/2025) Added modified script version, process_listmode_chunks.py, to be used for large input files. Script runs by loading the .Lis file in chunks of N MB, where N is a user-defined variable specified with -chunk-size or -c. For example, to use 1-MB chunks:

python process_listmode_chunks.py inputFile.Lis outFileName.csv -c 1

• The default chunk size is 2 MB.
• An input file may be large if $8\times$(displayed .Lis file size) exceeds or is on the order of your computer's available RAM, or if the non-chunk script otherwise fails.
• Anecdotal benchmark: a 2 GB file was processed in ~40 min, using a computer with 16 GB RAM and AMD Ryzen 7 3800X 8-Core Processor (3.90 GHz).
• ADC values are cast to Int16 to reduce the file size of the output .csv. Please take note if ADC values are expected to exceed 2¹⁵.
• The previous process_listmode.py script remains available for more verbose progress bars and debugging.