This document servers as the main user manual for the control software for the PAPA detector. The program was written for python 2.6 and requires the following libraries:
- DaqMx: A library from National Instruments for speaking interfacing with their digital IO cards. Specifically, we use the nicaiu.dll file.
- BmmServer4: A server program written by the SNS which records the spectrum on the neutron beam monitor. This program is part of the SNS dcom system.
- NumPy: A numerical library for python
- PySerial: A python library for communicating over a computer’s serial port.
- Current Listener: A LabView program on the motor server which controls the current in the power supplies. An energetic grad student should replace this with more python code in order to condense us down to a single language. Also, LabView VIs hate text based source control.
The recommended way to run the control system is to load up Control.py into an interactive python prompt. This can be done by using the -i command line switch on python. To simplify this process, a batch file is kept on the desktop of the control computer which will do this loading automatically.
Control.py defines a control object in the variable c. This object is the main interface for controlling the instrument. At any time, the command help(c) will display the documentation on all of the control object’s member functions.
To close the program, use the exit() function. This will kill all of the detector processes and handle the shutdown of the resources acquired by the program. Do not use the quit() command, as it will not kill the detector and instrument threads.
The instrument uses two different types of Kepco power supplies. There are eight 20A/20V power supplies used to power the triangle coils and four 10A/20V power supplies for the remaining solenoids. The triangle supplies are controlled via the triangle member function, which takes the power supply’s number and the desired current. For instance, c.triangle(3,-7) sets the current in the third power supply to -7A. The 10A power supplies are named flipper, guides, phase, and sample and can be adjust by the eponymous member function. For instance, c.triangle(4) sets the current in the triangle power supply to 4A.
The flippingrun member function starts data collection on a polarization measurement. The function takes one argument: a tuple that controls the amount of time spent in the spin up and spin down states. For instance, c.flippingrun((1,3)) takes 120 seconds of data in the first spin state, then 360 seconds of data in the second before repeating the process. The spin state is chosen by flipping the current in the guides power supply. As there is some overhead involved in flipping the currents, longer runs may benefit from having longer times given (e.g. c.flippingrun((10,30)) would spend 1200 seconds in the first spin state and 3600 in the second). For the best statistics, the times should be chosen so that the ratio between the time spent in the low count state to the time in the high count state is equal to the square root of the flipping ration.
To end a measurement, use the stop member function.
It may become necessay to change the settings on the PAPA detector. The current settings can be queried with the query member function, while the values can be set through the detectorParameter member function. Global variables q and d re.erence query and detectorParameter, respectively. . Here’s a list of the parameters that can be read and adjusted:
| Name | Command | Arguments | Read | Write | Comments |
|---|---|---|---|---|---|
| shutter | SO | 1 | T | T | |
| mode | AM | 1 | T | T | |
| pulse strobe | PS | 1 | T | T | |
| gate capture | GC | 1 | T | T | |
| reset timer polarity | RT | 1 | T | T | |
| power supply voltage | PV | 1 | T | T | |
| pmt power supply state | PE | 1 | T | T | |
| energy pmt power supply voltage | EV | 1 | T | T | |
| energy pmt power supply state | EE | 1 | T | T | |
| intensifier power supply voltage | IV | 1 | T | T | |
| intensifier power supply state | IE | 1 | T | T | |
| trigger thresholds | TE | 2 | T | T | |
| end event fraction for energy | TF | 1 | T | T | |
| trigger thresholds for papa strobe | TP | 2 | T | T | |
| end event fraction for papa strobe | TQ | 1 | T | T | |
| coincidence timer lead and lag | CT | 2 | T | T | |
| offset for ADC channel A | OA | 1 | T | T | |
| offset for ADC channel B | OB | 1 | T | T | |
| offset for ADC channel C | OC | 1 | T | T | |
| offset for ADC channel D | OD | 1 | T | T | |
| channel A filter | ?FA | T | F | ||
| channel D filter | ?FD | T | F | ||
| gray constant | ?BA | T | F | ||
| bit shift | ?BS | T | F | ||
| temperature set point for zone zero | ?TS0 | T | F | ||
| temperature set point for zone one | ?TS1 | T | F | ||
| kp gain for zone zero | KP0 | 1 | T | T | |
| kp gain for zone one | KP1 | 1 | T | T | |
| ki for zone zero | KI0 | 1 | T | T | |
| ki for zone one | KI1 | 1 | T | T | |
| kd for zone zero | ?KD0 | T | F | ||
| kd for zone one | ?KD1 | T | F | ||
| temperature for zone zero | ?TC0 | T | F | ||
| temperature for zone one | ?TC1 | T | F | ||
| gain for X0 | ?GX0 | 1 | T | F | |
| gain for X1 | ?GX1 | 1 | T | F | |
| gain for X2 | ?GX2 | 1 | T | F | |
| gain for X3 | ?GX3 | 1 | T | F | |
| gain for X4 | ?GX4 | 1 | T | F | |
| gain for X5 | ?GX5 | 1 | T | F | |
| gain for X6 | ?GX6 | 1 | T | F | |
| gain for X7 | ?GX7 | 1 | T | F | |
| gain for X8 | ?GX8 | 1 | T | F | |
| gain for X9 | ?GX9 | 1 | T | F | |
| gain for Y0 | ?GY0 | 1 | T | F | |
| gain for Y1 | ?GY1 | 1 | T | F | |
| gain for Y2 | ?GY2 | 1 | T | F | |
| gain for Y3 | ?GY3 | 1 | T | F | |
| gain for Y4 | ?GY4 | 1 | T | F | |
| gain for Y5 | ?GY5 | 1 | T | F | |
| gain for Y6 | ?GY6 | 1 | T | F | |
| gain for Y7 | ?GY7 | 1 | T | F | |
| gain for Y8 | ?GY8 | 1 | T | F | |
| gain for Y9 | ?GY9 | 1 | T | F | |
| gain for X | GX | 2 | F | T | First argmuent is PMT number Second Argument is Gain |
| gain for Y | GY | 2 | F | T | First argmuent is PMT number Second Argument is Gain |
| gain for strobe pmt | GS | 1 | T | T | |
| gain for threshold channel | GT | 1 | T | T | |
| gain for energy pmt | GE | 1 | T | T | |
| ADC offset voltage | AV | 1 | T | T | |
| serial number | ?SN | T | F | ||
| version | ?VS | T | F |
/-------------------\ /-----------------\ /-----------------\
. /----------\ . . Instrument . . Control .
. . Detector . .--------. /---------\ . . /-------\ .
. \----------/ . . . Monitor . .-----. . Coils . .
. . . \---------/ . . \-------/ .
. DetectorProcess . . /-----------\ . . /-------------\ .
. . . . XMLConfig . . . . XMLManifest . .
\-------------------/ . \-----------/ . . \-------------/ .
\-----------------/ \-----------------/