E 3 at Hahn Meitner Institute Berlin

TwoAxis Powder Diffractometer with Multicounter

The powder diffractometer E3 is equipped with a position sensitive detector (multicounter). It is installed at the beam tube T2.

Applications

The diffractometer can be used to investigate the following metallurgical and crystallographic problems:

Instrument description

The diffractometer is equipped with a curved position sensitive BF3 -multicounter (400 cells) of 2 = 80° with a resolution of 2 = 0.2°, the usable 2 range is 3° - 115°. The detector shall be replaced by a new curved position sensitive 3Hemulticounter (1024 cells) of 2 = 80° with a resolution of 2 mm (2 = 0.08°).

The 100 mm (in future 150 mm) high detector cells allow the integral measurement of the reflection profile and the detection of weak powder reflections or diffuse scattering contributions. A flexible choice of the wavelength between = 0.9 Å and 3.6 Å is achieved by three vertically focusing monochromators and two fixed takeoffangles.

The primary beam and its resolution is defined by a sapphire filter (reducing fast neutron contaminations), a removable graphite filter, two collimators (1 = 10', 30') and the monochromator in use (see table below). The local resolution of the measurements can be defined by automatically positioned primary and secondary diaphragms of adjustable geometry. Sample and detector installed on a "Tanzboden" are controlled by a VAX3200workstation via CAMAC instrumentation.


E 3                                                                 

Beam Tube:                   T2                                     

Monochromators:              Wavelengths at 2                       
                                  42.5° 65°                         

vertically focusing                                                 

Cu (220)                      0.92 1.37                             

Ge (311)                      1.22 1.84                             

HOPG (002)                     2.40 3.6                             

neutron flux                 2.3*106 n s-1 cm-2                     
                             (=2.4 Å, no collimation)               

Collimations:                1 = 10', 30'                           
                             2 = 10', 15', 30'                      

Maximal beam section at      60 x 30 mm2                            
sample position:                                                    

Detector:                    present: curved position sensitive     
                             BF3 multicounter                       
                             in future: Curved position sensitive   
                             3He multicounter                       

Radius:                      1500 mm                                

Channels:                    400 (in future 1024)                   

Angle Range (2):             3° - 115° (detector width 80°)         

Auxiliary Equipment:         Eulerian cradle with integrated        
                             xyztranslation device; xyztranslation  
                             device (400 kg); highToven (1200°C);   
                             focusing mirror heating device         
                             (2000°C);  cryostat; cryomagnet