Hardware

Dr. Westmeier GmbH works together with all major producers of hardware for nuclear applications. We supply any hardware item (detector, multi-channel-analyser, shielding, electronics, accessories, calibration material) or systems comprising of these parts. The Dr. Westmeier GmbH will assist you with the procurement of such units, installation and maintenance, in-house training, routine management and performance controls.
Moreover, we integrate spectrometry systems with our software SODIGAM for the high-precision analysis of scintillator spectra.

The most common detectors used for room-temperature scintillation spectrometry are:

  • NaI(Tl) detector which is relatively cheap and has resolution (FWHM at 662 keV) of 7.5% or better. NaI(Tl) detectors are available in sizes up to 8″x5″ and in many non-standard geometries for special applications.
  • LaBr3(Ce) detector which is more expensive than NaI(Tl) and has resolution (FWHM at 662 keV) of 3% or better.
  • CeBr3 detector having resolution of ~4% has very low internal activity (contamination) and is significantly cheaper than LaBr3(Ce).

Some details of sytems based on these detectors are given in the  sections below

NaI(TI)-Detektor

Gamma-ray spectrometry using scintillation detectors was once avoided mainly because of poor detector resolution and the lack of high precision spectrum analysis software. However, because of several new developments, scintillator spectrometry is now undergoing a spectacular renaissance.

Software tools have in the meantime been developed to quantitatively analyse even complex scintillator spectra.
The most suitable software is SODIGAM. It is the only program on the market that correctly assesses the shape of the baseline (i.e. the background under peaks) as well as the intrinsic shape of NaI(Tl), LaBr3(Ce) and CeBr3 scintillator peaks. The program is well-suited to accurately analyse small peaks sitting on a high background or even complex shoulder peaks.
Therefore, in many applications one can now use room-temperature scintillation spectrometers instead of low-temperature high-purity germanium systems without much loss of precision.

Significant advantages of scintillation detectors over HPGe are:

  • NO running costs and service personnel (no liquid nitrogen handling needed)
  • high mobility of the low-weight and small-size scintillation spectrometer
  • higher efficiency of the scintillator crystal
  • lower investment cost

The clear disadvantage of NaI(Tl) against HPGe is its poorer resolution. However, in many applications NaI(Tl) can take over measurements where the use LN2-cooled of HPGe was once mandatory. Some additional information about NaI(Tl) spectrometry systems is found  here.

LaBr3-Detektor

A new scintillator material was developed by Saint Gobain (Nemours, France) which is a strong competitor for cooled HPGe detectors. Detectors using the new LaBr3 crystal doped with Ce are called BrilLanCe 380 and they are available in sizes up to 3”x3” on a regular commercial basis.
For availability of larger size crystals, please contact us.

The new BrilLanCe detectors:

BrilLanCe 350 LaCl3(Ce) with approx. 10% Ce
BrilLanCe 380 LaBr3(Ce) with approx. 5% Ce
can have very good resolution of 3% or below. Spectra are well characterized in terms of peakshape and baseline (see .PDF).

The clear disadvantage of LaBr3 against HPGe is its poorer resolution. However, in many applications LaBr3 can take over measurements where the use of HPGe was once mandatory.

CeBr3 Detectors

The new detector material CeBr3 was developed by SCHOTT (Mainz, Germany) it has significant advantages over NaI(Tl) for energies above ~200 keV. The photoelectron yield is approx. 25% higher than in NaI(Tl), the resolution is clearly much better (see table below) and the efficiency above 200 keV is almost twice that of NaI(Tl).

Energy in keV Resolution NaI(Tl) in % Resolution CeBr3 in %
30 18 22
60 12 15
81 11 13,5
122 9 11
356 8 5
662 6,5 4
1332 4,9 3
2615 4,0 2

The major advantage of CeBr3 over LaBr3(Ce) is the fact that CeBr3 is almost free of internal contamination. Thus, CeBr3 detectors are well suitable for environmental surveys where the content of 40K in samples must be quantified.
CeBr3-crystals are available in cylindrical standard geometries 1“x1“, 1.5“x1.5“, 2“x2“ und 3“x3“. The mesure 1“x1“ means that the crystal has 1“    (25.4 mm) diameter and 1“ thickness. For availability of other sizes and shapes, contact us – we will support you as best we can.

M. info@westmeier.com
T. 06424 923000
F. 06424 923002

bMCA multi channel analyzer

We proudly inform that we are OEM traders of a new line of digital multichannel analysers for scintillation spectrometry. Technical highlights of bMCA are:

  • 25 MHz flash ADC
  • 256, 512, 1024, 2048 or 4096 channel spectrum length
  • HV up to 1500 Volt
  • digital and analog gain
  • LLD and ULD control
  • PHA and MCS measuring modes
  • integrated oscilloscope (input and processed signal)
  • full emulation software with spectrum handling
  • one-button start of high-precision spectrum analysis

 

bMCA is available in different versions for various applications:

  • bMCA-U: spectrometry with plug-on MCA and USB connection to the computer
  • bMCA-E: spectrometry with plug-on MCA and PoEthernet connection to the computer
  • bMCA-C: SCA counting providing TTL and/or analog outputs
  • bMCA-S: spectrometry through HV cable and USB connection to the computer. Technical data like bMCA-U.