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Purpose

These pages describe the Data Acquisition System (DAQ) for the BetaNMR (BNMR) and BetaNQR (BNQR) experiments at TRIUMF

Introduction

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

There are two separate experimental setups :

• 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 and bnqr. DAQ software specific to these experiments (MIDAS clients e.g. frontends) run the experiments - see #Software Components.

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 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 channels BNMR and BNQR at regular intervals. Both DAQ systems bnmr and bnqr are active.

Environment

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

• Integral (Type 1)
• Time Differential or TD (Type 2)
• Combination of the above two types

Experimental Modes

A number of different experimental modes are defined for each of Type 1 (Integral) and Type 2 (TD) #Environments. These allow different experimental modes to be run (e.g. Frequency scan, Na Cell scan). The modes used in recent years are shown in a brighter colour. These modes correspond to different programs downloaded into the PPG (i.e. to different pulse sequences) so are also known as PPG Modes. To understand what each experimental mode does, consult the appropriate timing diagram listed below.

Table 1 INTEGRAL and TIME DIFFERENTIAL Experimental (PPG) Modes

Table 1a: Type 1 Integral Modes Mode Name Run Parameters Timing Figure Scalers 10 Same as 1f 1a 1a 1a 1b 1b 1b Freq 1f 1f NaCell 1n 1n Laser 1d 1d Camp 1c 1c Fast * 1g Not available LCR ** 1j Not available *Combination of Modes 20 and 1f **Combination of Modes 20 and 1c

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Table 1b: Type 2 Differential Modes Mode Name Run Parameters Timing Figure SLR 20 20 2a 2a 2a 2b 2b 2b 2c 2c 2c 2d 2d 2d 2e 2e 2e this is a spacer a

Hardware Components

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

Table 2: Hardware Modules for each Experiment

Module	Description	Manual	VME Base Address	BNMR	BNQR
SIS3801 version E	multichannel scaler A	SIS3801	0x2800	yes	yes
SIS3801 version E	multichannel scaler B		0x1800	yes	no
PPG (Pulseblaster)	Pulse Programmable module	PPG Spincore Pulseblaster	0x8000	yes	yes
PSM	Pol Synthesizer module (RF)	PSM / PSMII AD9857 Quadrature Digital Upconverter	0xC00000	no	yes
PSMII	Pol Synthesizer module II (RF)		0xC00000	yes	no
MVME162	68040 board, cpu runs CAMP (VxWorks)			bnmrvw	polvw
VMIC	cpu runs frontend (Linux)			lxbnmr	lxbnqr

The names of the VMIC running the frontend and MVME162 (the CAMP host) for bnmr and bnqr experiments are shown in Table 2 above.

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 (differences between the two experiments are handled with ifdefs).

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.

The main software components of the bnmr and bnqr experiments are

Table 3: Software Components

Component	Purpose
frontend (runs on VMIC)	set up, operate and read hardware modules
rf_config	check PPG parameters, download program to PPG
mdarc	custom data logger saves data in MUD format
midbnmr	converts MIDAS format saved data files to save in MUD format
mheader	sends out CAMP and EPICS slow-control data to be saved in the MUD data file
fe_epics	sends experimental data to EPICS (can be read by control-room)
perlscripts	various perlscripts control changing experimental mode, checking and maintaining run numbering, etc.
autorun	automatic run controller
lcrplot	plots experimental data
physica	analyse data, reads MUD format files

Each of these components is described in more detail here.

DAQ Summary

The VMIC front end computer runs the frontend code which

• controls PSM,PPG, VMEIO
• acquires data from SIS MCS module(s), builds histograms
• acquires data from CAMP, EPICS
• sends the data out into the data buffer

The host computer (isdaq01)

• run all other software components
• starts/stops runs
• acquires the data from the data buffer
• logs the data
• monitors the experiment