Neutron beam

Cold neutron spectrum from NL4b (last section of 5.8m elliptical focussing) with an average energy
of 1.83 meV (6.7 Å).

Two measuring positions:

• P1 (larger samples):
  Beam size: 34 × 48 mm2
  Neutron flux: max. 6.5 · 10⁹ n/cm²s
  (2.4 · 10¹⁰ n/cm²s thermal n. eq.)
  
• P2 (small samples)
  with optional 1.1m elliptical guide
  Beam size: 16 × 19 mm2
  Neutron flux: max. 1.6 · 10¹⁰ n/cm²s
  (6.1 · 10¹⁰ n/cm²s thermal n. eq.)

Detection system

Two Compton-suppressed spectrometers (HPGe detectors: D1 60% and D2 36%; surrounded with NaI(Tl)/BGO and BGO scintillators respectiviely and connected in anticoincidence mode). Analogue electronics (NIM modules) and multichannel analyzer with integrated ADC.

Detection range of typically 80keV – 11 000keV (adjustable).

Measuring conditions

• Low vacuum (~0.5 mbar) possible
• Sample weight: units of mg – g
• Max. sample dimensions:
  ca. 40 × 40 x 40 mm3
• Automated measurement for max. 6 samples in a batch (vertical sample holder with 6 positions). Solid samples are usually sealed in thin FEP bags.

Data acquisition and analysis

• Linux based self developed software for the automated measurement of up to 6 samples in a batch run.
• Evaluation of the spectra and the calibration of the spectrometer (efficiency curve and non-linearity)  using the software Hypermet PC developed in Budapest.
• Determination of the elemental composition of samples using the Excel macro and Excel sheet package ProSpeRo.