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BNMR and BNQR Experiments at TRIUMF

This is the main page of the documentation for the Data Acquisition System (DAQ) for the BetaNMR (BNMR) and BetaNQR (BNQR) experiments at TRIUMF

Click here for a full list of all the pages in the BNMR documentation.

Introduction

The Data Acquisition System is based on the MIDAS data acquisition package.

There are two separate beamlines, BNMR and BNQR, each with its own experimental setup :

• bnmr running on the BNMR high-voltage platform
• bnqr running on the BNQR high-voltage platform

Each experimental setup has its own #Hardware Components (i.e. a VME crate containing DAQ modules). Each runs as a separate MIDAS experiment named bnmr or bnqr. DAQ software specific to these experiments (MIDAS clients) run the experiments - see #Software Components. Experimenters control the experiment using the MIDAS Web Server (mhttpd).

Beam Control

The main TRIUMF EPICS Control System is used to control the beam, which can be switched to either experiment's beamline. There are two Beam Modes that the experiments can be run in:

single channel mode

where the beam is sent to one beamline (channel) only, either BNMR or BNQR. Only one of the DAQ systems bnmr or bnqr is active.

dual channel mode

where the beam is switched between the two beamlines (channels) BNMR and BNQR at regular intervals. Both DAQ systems bnmr and bnqr are active.

Experimental modes

For both experiments, two types of environment are defined (cf MUSR experiments):

• Integral or TI (Type 1)
• Time Differential or TD (Type 2)

There are two separate concepts that use similar naming schemes (e.g. 1f, 20) - the timing of pulses issued by the PPG and the name of the overall experimental mode. The overall mode determines both which timing scheme is run, as well as which hardware is scanned during the run (e.g. RF frequency, Na cell voltage). Multiple experimental modes may use the same PPG timing scheme (e.g. modes 1c, 1d, 1e, 1n use the PPG timing scheme called 1n).

Below is a full list of experimental modes, with the most common ones highlighted in bold. More details about each mode can be found on the BNMR mode changer page and the BNQR mode changer page.

Experimental modes

Mode name	PPG timing	BNMR?	BNQR?	Comment
10	10	✓	✓	No RF, nothing scanned
1a	1a	✓	✓	Scan RF frequency
1b	1b	✓	✓	Scan RF frequency
1c	1n	✓	✓	Scan settings on a Camp device
1d	1n	✓	✓	Scan the laser intensity
1e	1n		✓	Scan the magnetic field strength
1f	1f	✓	✓	Scan RF frequency
1g	20	✓	✓	Scan RF frequency
1j	20	✓	✓	Scan settings on a Camp device
1n	1n	✓	✓	Scan the Rb cell voltage or any other EPICS device
1w	1w	✓		Parametric scan of RF frequencies
1x	1f	✓	✓	Scan RF frequency with one region at higher resolution
20	20	✓	✓	Nothing scanned
2a	2a	✓	✓	Scan RF frequency
2b	2b	✓	✓	Scan RF frequency
2d	1b	✓	✓	RF on, nothing scanned
2e	2e	✓	✓	Scan RF frequency
2f	2f	✓	✓	Scan RF frequency
2h	20		✓	Read alpha channels from scalers
2s	2s	✓		Spin-echo
2w	2w	✓		RF Wurst modulation

Any of these modes may be run in single channel mode. Only Type 2 modes may be run in dual channel mode.

Users change which mode is active using the webpages for each experiment, which in turn interact with the mode changer python script.

Hardware Components

DAQ hardware components for each DAQ system (BNMR/BNQR) include the following VME modules:

Table 2: VME Modules for each Experiment

Module	Description	VME Base Address	BNMR?	BNQR?	Manual
SIS3801 version E	multichannel scaler A	0x2800	✓		SIS3801 manual (PDF)
SIS3801 version E	multichannel scaler B	0x1800	✓
SIS3820	multichannel scaler B	0x38000000		✓	SIS3820 manual (PDF)
PPG (Pulseblaster)	Pulse Programmer	0x8000	✓	✓	PPG manual (PDF) Spincore Pulseblaster (PDF)
PSM	Pol Synthesizer module (RF)	0x820000		✓	PSM
PSMII	Pol Synthesizer module II (RF)	0x820000
PSMIII	Pol Synthesizer module III(RF)	0x820000	✓
NIMIO32	Input/Output Register	0x100000	✓	✓	NIMIO32
MVME162	68040 board (VxWorks) that runs CAMP		✓ (bnmrvw)	✓ (polvw)
VMIC	Linux machine in VME crate that runs frontend		✓ (lxbnmr)	✓ (lxbnqr)

The connections between the DAQ VME Modules are shown in BNMR DAQ Hardware Connections.

Software Components

The DAQ system is based on the MIDAS package. Data acquisition software to run the bnmr and bnqr experiments has been written to run under MIDAS. This includes the frontend, custom logger etc. This software is mostly common to both experiments, with the differences between each experiment handled by Midas ODB settings (most things) and a compile-time flag (choosing whether to build the febnmr or febnqr frontend).

The experiment is controlled using the MIDAS webserver (mhttpd). Due to the large number of experimental parameters required, Midas custom pages have been written for the experimenters to control and monitor their experiment.

The custom logger (mdarc/midbnmr) saves the data into MUSR MUD format files, and the MUSR CAMP slow control system is used for slow controls. Analysis is done by physica.

The DAQ software components are started by the script start-all and stopped by the script kill-all. These include standard MIDAS utilities (e.g. mhttpd, mlogger, mserver) as well as components specific to the bnmr and bnqr experiments.

The main DAQ software components specific to the bnmr and bnqr experiments are shown in the table below. A full ist can be found on the software overview page.

Table 3: DAQ Software Components

Component	Host	Experiment	Purpose
Midas frontends
febnmr_32bit.exe	lxbnmr	bnmr	the frontend sets up, reads out hardware modules, sends histograms. The frontend code for both experiments is identical.
febnqr_32bit.exe	lxbnqr	bnqr
Midas clients - configuration
mode_changer.py	isdaq01	both	changes between experimental modes and between real/test runs
rf_calculator_fe.py	isdaq01	both	generates PPG program based on user-specified ODB parameters; reports calculated quantities in the ODB; sets up links in the ODB that should be stored in MUD files
ppg_compiler_fe.py	isdaq01	both	low-level conversion of PPG program to PPG bytecode
Midas clients - logging
bnxr_logger.exe	isdaq01	both	writes data to MUD files. Reads information from midas banks (for scaler histograms), EPICS, and CAMP
logger_cleanup.exe	isdaq01	both	cleans up and archives any saved run files that were not properly archived. Run by user occasionally as needed.
run_comment_editor.py	isdaq01	both	responds to comments written by user in text box on the status page, saving to disk and/or midas banks
Other
autorun	isdaq01	both	automatic run controller
scripts	isdaq01	both	scripts perform important functions e.g. kill-all, start-all. Scripts run at the begin and end of each run send information to the elog etc.
camp	bnmrvw	bnmr	MUSR slow control system
	polvw	bnqr

Click the links in the above table for more details of each program.

Not listed above are various automated test programs for both the C++ and python programs. There are also some interactive test programs for debugging hardware issues.

Note that the DAQ was rewritten in 2020. Details of the rewritten in 2020. Details of the differences between the new DAQ (documented here) and legacy DAQ (documentation removed) can be found on the 2020 rewrite page.

DAQ Summary

The VMIC front end computer

• runs the frontend code which
  • controls PSM,PPG, VMEIO, Scaler modules
  • acquires data from SIS MCS (scaler) module(s), builds histograms
  • uses channel access to control EPICS variable(s) (e.g. helicity)
  • periodically sends the data out into the data buffer

The host computer (isdaq01)

• runs all other software components which
  • acquire the data from the data buffer
  • log the data
  • monitor the experiment
  • start/stop runs

Tasks to be done before each beamtime

• If this is the first beamtime of the year, create a new data directory and reset the run numbers.
• If there have been changes to the code that affect the ODB structure, ensure saved settings have been updated to contain the new variables.
• Always edit the bnmr user's cronjob (using crontab -e) to specify the schedule number and date range to include in the generated Excel file. See the supported arguments to beamtime_to_excel.py and the TRIUMF beamtime schedule.
• Strongly recommended to try changing between a few common modes (e.g. 20, 1f, 1n, and back to 20) and ensure the run can start (in test mode, not real mode). You may need to disable "switching" checks on the status page if the beamline is not currently configured for BNMR/BNQR.

Nomenclature

In this document, " bnmr or bnqr " may be written as " bn[mq]r "

For example, directories :

/home/bnmr/online/bnmr spc and spc /home/bnqr/online/bnqr

are referred to by shortcuts such as

space /home/bn[nm]r/online/b[nm]r spc and spc ~/online/b[nm]r

Alternatively, these directories may be written as

• /home/<experiment>/online/<beamline>
• /home/<expt>/online/<beamline>
• ~/online/<beamline>

where <experiment> <expt> and <beamline> are bnmr or bnqr.