TwoThetaP07

At P07 the two-theta angle corresponds to a translation and 3 rotations. A special Tango server has been created to server this purpose.

<device>
 <name>tth</name>
 <type>type_tango</type>
 <module>motor_tango</module>
 <device>p07/twotheta/eh2a.01</device>
 <control>tango</control>
 <hostname>hasgksspp07eh2a:10000</hostname>
</device>

Figure 67.1: Jive: Properties of the TwoThetaP07 server

Here is the list of the attributes:

Figure 67.2: Jive: The attributes the TwoThetaP07 server

We have the following relations for a requested tth value at a specific energy:

 
#define LAMBDA_TO_E 12398.424
#define RAD_TO_DEGREE 57.295780 

xdt   AxisTranslationDetector
rdt   AxisRotationDetector
rcoll AxisRotationCollimator
oman  AxisRotationAnalyzer
l     AxisDistanceSampleDetector

--- setting a new tth

theta_ana = RAD_TO_DEGREE* asin( 12398.424/E/2/d)
  E [eV]
  d [Angstr.]

if FlagUseAnalyzer
  rdt = tth + 2*theta_ana
  rcoll = -2*theta_ana
  oman = theta_ana
  xdt = -l*tan( tth/RAD_TO_DEGREE)
else
  rdt = tth
  rcoll = 0
  oman = 0
  xdt = -l*tan( tth/RAD_TO_DEGREE)
  
--- reading tth

  tth = RAD_TO_DEGREE * atan( -xdt/l);

Note that there is a beamline-specific-code widget for the device which is described in the Online -tki manual.