β- & β/γ-Spectrometer

HPGe, NaI or thick plastic scintillator in combination with beta-sensitive (gas or very thin plastic scintillator) detector all in a sandwich lead shield.

Application for nuclear sample mesurements

  • Beta and Beta/Gamma spectrometry systems for sample measurements.

  • As central E-detectors for spectrometry plastic scintillators but also NaI & HPGe detectors can be used, both for simultaneous gamma spectrometry also.

  • In combination with a high beta-sensitive thin plastic scintillator or gas detector used as dE-detector for very high beta separation.

For National and international organizations and companies in

  • Environmental, health and food surveillance and laboratories

  • Universities, research centers, nuclear medicine

  • Industry- and nuclear technology

  • Dismantling, consulting, waste management

  • Civil defense, emergency response, border, safety, security and access control

Beta Spectrometry Systems

Important Highlights:


  • Using one of the ISuS dE-detectors beta particles can be separated almost perfectly from photons.

  • Separation factors of more than 1000 are realizable


  • Related to a 2π-source emission geometry using a Sr/Y-90 source in equilibrium about more than the half  of it.

Lower Limit of Detection (LLD)

  • Depends naturally on the selected detection system, the source geometry & sample preparation and of the nuclide matrix in the sample. LLD's down to 3 mBq/g sample weight are attainable.

Example for dE Detector Data:

  • Gas flow -detector (standard: Methane, or other Gas)

  • Geometry: about 16 mm thick, ~ 70 or 120 mm sensitive inner diameter, Outer diameter: 98 as well as 160 mm

  • Type: Transmission-Detector

  • Beta-sensitivity: down to about 50 keV

  • Beta/Gamma Separation Power: about 1000

Substantial Advantages
Using point sources, filter samples or thin Petrie-shells with as lower self-absorption as possible

  • then no chemical sample preparation is necessary

  • then the filters sample can be used close on a detector endcap,

  • for liquids sources mostly an evaporation is sufficient

Beta and/or photon spectra can be detemined depedent from the system configuration.


Pure Beta-Spectra

The linear spectra show the perfect beta distributions of 3 Sr/Y-90 filter samples (down to 10 mBq) measured with a plastic scintillation detector system. The low energy Sr-90 and the high energy Y-90 distribution is shown in the spectra and can be separated.



  • 128 mBq (pink)

  • 50 mBq (magenta)

  • 10 mBq (red)

  • background (black)


and down:

with background subtraction


​Sr/Y-90 source measured with a HPGe decetor without lead shield (black) and in beta-coincidence with a gas detector direct in front of the HPGe endcap (red). It shows the pure beta-distribution (red) through the perfect beta selection of the gas detector in log-mode.


Determine the lowest level Beta/Gamma-Activities with minimum of sample preparation “simultaneously” by Beta- and Photon-Spectrometry


β- & β/γ-