IDQ ID801 TDC (Time to Digital Converter) or "Time Tagging Box"

This package is developed within the advisory of the Gallicchio Research Group, Harvey Mudd College.

It has a fast counter with a period ("native bin") of 81 ps. It outputs the value of this counter along with which channel saw the rising edge. This instruction assumes that you have the latest version of firmware updated on the physical IDQ ID801. Firmware update is contained with the official manual provided by the IDQ company itself (you should contact them directly if you own the device).

Table of Contents

• IDQ ID801 TDC (Time to Digital Converter) or "Time Tagging Box"
• Table of Contents
  • Required setup to interface with IDQ devices
  • Python module that utilizes C library shared-object
  • Python-based publisher-subscriber or server-client pattern
  • Troubleshooting

Required setup to interface with IDQ devices

grant the permission to manage the IDQ USB device by running the following shell command:

sudo vim /etc/udev/rules.d/idq.rules

then, add the following lines to the file and press :wq to save and quit

# Make IDQ devices available to all users
SUBSYSTEMS=="usb", ATTRS{idVendor}=="16c0", MODE="0660"

install the package by running the following shell command:

pip install idq-id801

Python module that utilizes C library shared-object

I implemented a Python interface that connects to the C library shared-object. This module allows for simple integration with other Python scripts. The use cases are laid out in this example notebook.

A Python script to try is the real-time plotter that you can call by the following shell command:

# This is an example for configurations below:
# exposure: 100ms
# coincidence window: 500TDC
# switch_termination: off
# save: do not save to CSV file
# A graph: plot channels "1" and "2"
# B graph: plot channel "1/2" (coincidence between channels "1" and "2")
python3 real-time_plotter.py -e 100 -w 500 -t 0 -A "1" "2" -B "1/2"  

To record the raw timestamps from the device record timestamps could be used:

python3 record_timestamps.py -e 100 -b 10_000  # to record all timestamps at 100ms exposure and 10_000 CSV writing batch size

Python-based publisher-subscriber or server-client pattern

To meet the need for accessing the coincidence data from the ID801 from multiple scripts at the same time, Next O. comes up with two distinct patterns to tackle this:

• publisher-subscriber: good for retrieving the same data across multiple scripts simultaneously with no side-effect to the ID801 main device.
• server-client: good for retrieving specific data for each script's goal simultaneously with possible reconfiguration of the ID801 main device

To start the publisher, we can run:

python3 id801_publisher.py  # this will spin up the publisher of ID801 device

To start the server, we can run:

python3 id801_server.py  # this will spin up the server of ID801 device

To see the example of how to request/subscribe to the server, refer ID801_client script that contains the client object API and is executable to fetch the data every 1 second.

Troubleshooting

If no information is retrieved from the device but no error is shown, try running python3 -m pytest -v to test if the device is working correctly. Note that you have to enable to channels first unless no channel is turned on by default.