The Converter GUI

This GUI controls a motor that puts in and out of the photon beam a piece of metal where photons create pairs that are detected and give us an information about the flux of the photon beam. The device is revolving around the motor axis.

It is also able in conjunction with the forward_scaler GUI (Figure 4.6) able to perform a photon beam scan, moving a wire into the beam when the scaler measures the change in counting rates.

How to launch it

Launching the GUI is very easy once the GUI_launch GUI (see section 4.2) is up. Simply click on the left popup menu and select 'converter'. A window (Figure 4.11) should shortly pop-up on the screen.

**Figure 4.11:** The Converter GUI window
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How to use it

a few buttons and some displays

Table 4.21: The Converter Panel
[0] 2l| Panel

[0.a] Display the absolute position of the wheel in degree. The value don't stay in a [0,360[ interval.

Buttons The button puts the Converter at the requested position.

**Table 4.21:** The Converter Panel
[0]	2l\| Panel
	[0.a]	Display the absolute position of the wheel in degree. The value don't stay in a [0,360[ interval.
	Buttons	The button puts the Converter at the requested position.

Table 4.22: The Converter Calibration Panel
[1] 2l|Calibration Panel

-- Not implemented

**Table 4.22:** The Converter Calibration Panel
[1]	2l\|Calibration Panel
	--	Not implemented

Table 4.23: The Converter Home Panel
[2] 2l|Home Panel

[2.a] This field will display ``At Home'' when the home switch is fired and ``Going Home''when in the process of calibrating itself on the Home Switch (see bellow [2.b])

[2.a] Clicking this button makes the wheel revolving until it reach the switch, and restore the calibration.

**Table 4.23:** The Converter Home Panel
[2]	2l\|Home Panel
	[2.a]	This field will display ``At Home'' when the home switch is fired and ``Going Home''when in the process of calibrating itself on the Home Switch (see bellow [2.b])
	[2.a]	Clicking this button makes the wheel revolving until it reach the switch, and restore the calibration.

Table 4.24: The Converter Scan Panel
[3] 2l|Scan Panel

It contains every control to perform a beam scan. It is described in chapter 5.

**Table 4.24:** The Converter Scan Panel
[3]	2l\|Scan Panel
		It contains every control to perform a beam scan. It is described in chapter 5.

Table 4.25: The Converter Help Panel
[4] 2l|Help Panel

[4.a] This button is to be clicked when the system seems to respond no more to the commands. It exits, as nicely as possible every loop the SNL program could be locked in.

[4.b] This popup-menu will allow you to open the help window or the ``expert'' GUI window (the last one is not documented).

[4.a] PANIC :

**Table 4.25:** The Converter Help Panel
[4]	2l\|Help Panel
	[4.a]	This button is to be clicked when the system seems to respond no more to the commands. It exits, as nicely as possible every loop the SNL program could be locked in.
	[4.b]	This popup-menu will allow you to open the help window or the ``expert'' GUI window (the last one is not documented).
	[4.a]	PANIC :

Hardware and Software

The Converter is a simple sheet of aluminum that can be put in and out of the beam by the motor. The incident photons create electrons pairs that are detected in coincidence by the scintillators. The number of pairs created, and detected is proportional to the flux of the beam through the Converter. This is a mean to measure the beam intensity.

File informations

The application is under CVS monitoring and is known as frwd_target ¹². To check it out, type cvs checkout frwd_target. Then build it by typing make in the main directory.