Sample environments
Sample table
One standard sample set-up is the sample table with a vertical translator, a xy-table and a rotation table. Optionally, another linear translator stage or a double goniometer can be mounted on the rotation table. The available motor axes for the sample table are defined as follows:
- saz
vertical translation of the sample table
- say
horizontal translation parallel to the neutron beam direction
- sax
horizontal translation perpendicular to the neutron beam
- som
rotation around the vertical axis ω
- gphi
rotation around the horizontal axis Φ
- gtheta
rotation around the horizontal axis Θ, Θ ⊥ Φ ⊥ ω
- sposi
horizontal translation. Linear translation stage can be mounted on the rotation table and is used for the movement of the temperature controlled (Haake temperature controler, the Section called Haake temperature controller) sample holder.
st Status listing for st st.omega = 0.504000 st.x = 12.965000 st.y = -18.992001 st.z = 106.121002 st.posi = 173.875000 |
st pos P1 |
Haake temperature controller
This is sort of a buck full of water equipped with a temperature control system. The RS-232 interface of this device can only be operated at 4800 baud max. This is why it has to be connected to the serial printer port of the Macintosh serial port server computer. This makes the channel number to use for initialisation a 1 always. The driver for this device has been realised in the Tcl extension language of the SICS server. A prerequisite for the usage of this device is that the file hakle.tcl is sourced in the SICS initialisation file and the command inihaakearray has been published. Installing the Haake into SICS requires two steps: first create an array with initialisation parameters, second install the device with evfactory. A command procedure is supplied for the first step. Thus the initialisation sequence becomes:
inihaakearray <name-of-array> <macintosh-computer> <name> <port> <channel> evfactory new temperature tcl <name-of-array> |
inihaakearray eimer lnsa10.psi.ch 4000 1 evfactory new temperature tcl eimer |
The Haake Thermostat understands a single special subcommand: sensor. The thermostat may be equipped with an external sensor for controlling and reading. The subcommand sensor allows to switch between the two. The exact syntax is:
temperature sensor <val> |
Bruker electromagnet
This is the controller for the large magnet at SANS. The controller is a box the size of a chest of drawers. This controller can be operated in one out of two modes: in field mode the current for the magnet is controlled via an external hall sensor at the magnet. In current mode, the output current of the device is controlled. This magnet can be configured into SICS with a command syntax like this:
evfactory new <name> bruker <Mac-PC> <Mac-port> <Mac-channel> |
evfactory new magnet bruker lnsa10.psi.ch 4000 9 |
In addition to the standard environment controller commands this magnet controller understands the following special commands:
- magnet polarity
Prints the current polarity setting of the controller. Possible answers are plus, minus and busy. The latter indicates that the controller is in the process of switching polarity after a command had been given to switch it.
- magnet polarity <val>
sets a new polarity for the controller. Possible values for <val> are minus or plus. The meaning is self explaining.
- magnet mode
Prints the current control mode of the controller. Possible answers are field for control via hall sensor or current for current control.
- magnet mode <val>
sets a new control mode for the controller. Possible values for <val> are field or current. The meaning is explained above.
- magnet field
reads the magnets hall sensor independent of the control mode.
- magnet current
reads the magnets output current independent of the control mode.
Warning There is a gotcha with this. If you type only magnet a value will be returned. The meaning of this value is dependent on the selected control mode. In current mode it is a current, in field mode it is a magnetic field. This is so in order to support SICS control logic. You can read values at all times explicitly using magnet current or magnet field.
Sample holder for electro magnet
Another standard sample seup is a vacuum chamber, which is directly connected to the collimator and detector tubes, so that the SANS can be operated at about 10-2 mbar in a single vacuum without windows or with thin aluminium or sapphire windows to work at ambient pressure or at vacuum conditions down to 10-6 mbar. The chamber is large enough to carry an electromagnet. For this setup a sample changer with an optional heated sample position is available. This sample changer can be moved vertically by 245 mm and can also be rotated by ±10 degree. The two available motors are defined as follows:
- mz
moves the electromagnet sample holder in vertical direction.
- mom
rotates the sample around the vertical axis ω by ±10 degree.
msh Status listing for msh msh.z = 0.000000 msh.omega = 0.000000 |
Eurotherm temperature controller
At SANS there is a Eurotherm temperature controller for the sample heater available. This and probably other Eurotherm controllers can be configured into SICS with the following command. The Eurotherm needs to be connected with a nullmodem adapter.
EVFactory new <name> euro <computer> <port> <channel> |
| Warning | |
|---|---|---|
The Eurotherm needs a RS-232 port with an unusual configuration: 7bits, even parity, 1 stop bit. Currently only the SANS Macintosh port 13 (the last in the upper serial port connection box) is configured like this! Thus, an example for SANS and the name temperature looks like:
|
The Eurotherm needs to operate in the EI-bisynch protocoll mode. This has to be configured manually. For details see the manual coming with the controller.
The weird protocol spoken by the Eurotherm requires very special control characters. Therefore the send functionality usually supported by a SICS environment controller could not be implemented.
ITC-4 and ITC-503 temperature controller
*outdated controllers, will be replaced*