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What is Midas

"MIDAS" is an acronym for Maximum Integrated Data Acquisition System.

MIDAS is a general-purpose system for event-based data acquisition in small and medium scale Physics experiments. It is an on-going development at the Paul Scherrer Institute (Switzerland) and at TRIUMF (Canada), since 1993. Presently, focus is on multi-threading, web interface (JSON).

It is not to be confused with MIDAS (Multi Instance Data Acquisition System) from UK, or any of the MIDAS (Mobile Instrumentation Data Acquisition System), or MIDAS digital and analogue consoles and finally with MIDAS Brakes and Mufflers!

MIDAS is based on a modular networking capability and a central database system. MIDAS consists of a C library and several applications, which can run on many different platforms (i.e. operating systems) such as UNIX-like, Windows NT, VxWorks etc. While the system is already in use in many laboratories, the development continues with addition of new features and tools. Recent developments involve multi-threading, FGPA/Linux support, MSCB extension.

MIDAS has been designed for small and medium experiments. It can be used in distributed environments where one or more frontends (application acquiring the data from the hardware) are connected to the backend (application handling the gathering of the data from the frontend and managing the run sequence) via the network (i.e.Ethernet).

What Midas can do for you

In a few words, Midas can:

  • Collect data from local and/or remote hardware sources within your defined experiment.
  • Provides the mean to configure your hardware.
  • Manages the data flow and the control flow.
  • Provides tools for data and data flow monitoring (console and web applications).
  • Implement experiment access security.
  • Records the data to common storage media (disk, tape, ftp).
  • Includes programming layer to interface the data stream to your favorite data analysis package.


In the early '90s, based on a previous Data Acquisition system running under MS-DOS with network capability (HIX), Dr. Stefan Ritt at Paul Sherrer Institute PSI (Switzerland) started coding a new set of applications which would be OS independent. At that time, OS such as VMS, ULTRIX, VxWorks and Windows were available. The first deployment of Midas was for the "Canadian High Acceptance Orbital Spectrometer" (CHAOS) experimental facility at TRIUMF (Canada). Network based, the data were collected from a VME processor running VxWorks (collecting CAMAC, FastBus & VME data) and sending them to a backend computer running VMS and later ULTRIX.

Since then, Midas has been deployed on all major experiments at TRIUMF and PSI. It is also used around the world in over 80 locations. From simple workbench test setups to world class experiments such as PiBeta - muon decay MEG (PSI, Switzerland) - trapping antihydrogen atoms ALPHA (CERN, Switzerland) - neutrino oscillation T2K(J-Parc, Japan) - Decay study Pienu - precision muon measurement Twist (TRIUMF, Canada) - Dark Matter search DEAP (Sudbury, Canada) - Neutron Capture DANCE (Los Alamos, USA).

Midas has demonstrated its versatile capabilities and proven to be a mature and modern Data Acquisition Software package. A non-exhaustive list of experiments can be found here.

Recent Developments

  • July 2013 : Stefan Ritt visit at Triumf
    • Midas code from local SVN repository to Bitbucket cloud based GIT repository Tmidas
    • Implementation of multi-threading transition
    • New Midas web page
    • JSON, JSON-P for custom Midas web page support
  • Jan 2014 : New History Logging scheme "FILE"
  • July 2015 : Stefan Ritt visit at Triumf
  • August 2015 : Important Network Security upgrades:
    • Default MIDAS is now secure (clients must run on localhost only)
    • Network connections must be explicity allowed (see Security)
    • mhttpd uses secure HTTPS connections
  • January 2016 : mjson-rpc functions added to Javascript libary mhttpd.js - see mjsonrpc
  • July 2017
    • New web page layout with menu buttons on left side and alarm and message display on every page
    • New custom pages based on the mjson-rpc layer - see Custom Pages 2017

Overall Midas system diagram

A graphical view of the generic acquisition components forming the MIDAS DAQ

Midas Core

A general description of the different components composing the Midas Data Acquisition package