Prisma technical information

Technical information

Technical Summary


Inelastic Detector Bank (Prisma-3)

Final flight paths 
Sample to front analyser (LSF)0.600m
Front analyser to rear analyser * (LFR)0.045m
Rear analyser to detector * (LRD)0.211m
AnalysersPyrolytic graphite (0 0 2)
Width: 45mm
Height: 55mm
Detectors5 ½" 10 atm 3He gas tubes (Reuter Stokes)
Final collimationHorizontal: 30' - nil, 60' - nil, 30' - 60'
Vertical: 5°
Final energy3 meV < Ef < 20 meV
Angular range-120° to 0°
Resolution30'-60' : dEf / Ef = 4%
60'-nil : dEf / Ef = (2.3+0.5Ef)%
Note:
  1. Lengths marked * are defined when LFR is at 90° LSF (see schematic drawing of PRISMA-3).
  2. Pyrolytic graphite filters are available to remove second order contamination.
  3. Beryllium filters are available for use with Ef < 5 meV.


Inelastic Detector Bank (Prisma-4)

Final flight path0.825m - 0.832m
Detectors16 ¼" 20atm 3He gas tubes (Reuter Stokes)
Angular separation of detector arms
Final collimationHorizontal: 10', 30'
Vertical: 1° - 3°
Angular range-40°-133°


Instrument Parameters


Beamline 
Moderator95 K Methane poisoned at 2.25cm
Incident flight path

9.000m
Width: 20mm
Height: 40mm

Beam size(nominal: aperture adjustable to tailor beam size)
3-axis goniometer at sample positionGX: ± 15°
GY: ± 15°
Omega: ± 180°
Rotating detector tablePhi: ± 140°
Line-up detectors

5 ¼" 20atm 3He gas tubes (Reuter Stokes) at +90°

Final flight path: 1.056m

Incident energy3-250meV
Monitor 1 position-1.060m
Monitor 2 position-0.491m
Monitor 3 position1.066m
Data acquisition

Digital Alphastation 500/333
ISIS DAE I
LabView & EtherCamac sample environment control

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