The laboratory of the Van de Graaff accelerator is devoted to basic and applied research in experimental nuclear physics. Applications include testing and calibration of radiation detectors and the development of analytical methods in related areas (material and surface analysis, high-energy physics, space-related research). The laboratory is part of the Institute of Experimental and Applied Physics (UTEF) of the Czech Technical University (CTU) in Prague. Besides serving as a source of light ions the facility serves namely as tunable source of mono-energetic neutrons in relatively wide energy range (100 keV - 19 MeV). Experiments are mainly performed with charged particles (p,d,4He) and fast neutrons (from D-T, D-D and p-T reactions). In addition to the accelerator, the laboratory houses two stations of discrete gamma rays (described below). Access to the accelerator, beam guides and experimental chambers as well as the ESA gamma-ray stations (links included below) is possible all year round (see contacts).

VdG_accel.png, 44kB FIG. 1: VdG accelerator and beam guides.

Light ion beams & tunable mono-energetic neutron sources

Continuous beams are provided as follows. Light ions can be also provided in low intensity (down to 10^3/cm^2/s). Neutrons of discrete energy (accuracy few %) are provided in the indicated ranges. The neutron sources are calibrated and monitored with active devices (liquid scintillator NE 213, 3He Bonner sphere) with online display and evaluation.

light ions monoenergetic neutrons
protons E = 0.2 - 2.2 MeV     I = 0.5 - 10 uA                     D-T: E = 14.1 - 18.9 MeV     Φ = 103-5 n/cm2/s
deuterons     E = 0.2 - 2.2 MeV I = 0.5 - 10 uA D-D: E = 2.5 - 5.7 MeV Φ = 102-4 n/cm2/s
4He E = 300 keV/u - 2.2 MeV/u I = ~ uA p-T:     E = 0.03 - 1.7 MeV Φ = 103-5 n/cm2/s
12C,14N (newly) E = 300 keV/u - 2.2 MeV/u I = ~ uA     

Accelerator beam guides

The accelerator is equipped with 5 operating beam guides on which experimental setups are mounted. Guides 0,P1,P2,P3 deliver charged particle beams, guides L2,L3 provide the neutron sources.

layout.png, 44kB FIG. 2: Layout of the VdG accelerator beam guides.

Experiments/techniques, vacuum chambers, installed detectors/monitors, DAQ readout electronics

Experimental setups are mounted on the 5 installed beam guides for a number of techniques (listed). Vacuum level is 10^-5 mbar. Most lines are equipped with turbo-molecular vacuum pumps. The laboratory is equipped with a range of coaxial cable lines for transmission of measured signals from the accelerator hall to the control room and specially to the DAQ and evaluation room including several Ethernet lines for intranet within (after registration with the network administrator) as well as for remote transmission of data over the Internet. The laboratory is also able to ensure, if necessary, supply of liquid nitrogen and liquid helium. We also provide dosimetric monitoring service with our own experiments dosimeters.

  • Analytical methods: PIXE, PIGE, RBS
  • Polarized neutron beam on polarized D target
  • Tagged neutrons
  • Reactions for astrophysics
  • Light ion irradiations
  • Dark-Matter experiment (X17)
        Detectors and radiation monitors  
  • Charged particle detectors: Si diodes
  • Liquid scintillator NE213 - neutron monitor
  • 3He Bonner sphere - neutron monitor
  • X-ray Ge detector
  • Gamma-ray HPGe detector
  • Pixel detector Medipix2, Timepix and Timepix3
  • Fission fragment ionization chamber
        Vacuum chambers 
  • ∅ = 80 cm (P2)
  • ∅ = 60 cm (P3)
        DAQ readout electronics
  • Spectrometric NIM chain for charged particles (NIM modules, MCA)
  • Fast spectrometric chain (resolution < 2 ns)
  • Multi-parametric DAQ system (CAMAC, ADC, TDCs, online disply software)
  • Integrated DAQ systems for online display of neutron monitors

Further facilities

The laboratory houses also the following independent facilities:

  • ESA Stationary wide dynamic range calibration gamma-ray station.
  • ESA Portable calibration gamma-ray station.
  • Am-Be neutron source (activity 10 GBq)
  • Gamma-gamma coincidence system equipped with two HPGe detectors
  • Polarization experiment for spin physics (polarized beam + polarized target)
  • Cryogenic system for ultra-cold experiments (20 mK)


The team of the laboratory:

  • Michael Solar (administrator)
  • Rudolf Sykora (scientific head, physics experiments)    
  • Stanislav Pospisil (former director of IEAP CTU)
  • Ivan Wilhelm (external adviser - polarization experiment)
  • Hugo Natal da Luz (physics experiments)    
  • Zdenek Kohout (experiments, tagged neutrons)
  • Tomas Slavicek (ESA gamma-ray stations)
  • Jan Broulim (Gamma-gamma coincidence system)
  • Jan Svejda (accelerator operator)
  • Jaroslav Cerny (beam guide operator)
  • Jaroslav Petrik (accelerator/beam guide support)

Beam schedule & Contact

Beam/source time schedule: 2022, 2021, 2020, 2019, 2018, 2017, 2016, 2015, 2014, 2013.

User/beam time *.DOC form or *.PDF form.

The laboratory is located in the campus Troja, Prague 8 (see map - entrance shown by red arrow). See also interactive map.

Visitors and interested users are referred to contact:


Direct research and primary results obtained by the operator of large research infrastructure

Results obtained by users at the VdG facility



The accelerator and the laboratory are operated and upgraded in frame of the research funding grant "VdG Research infrastructure" by the Ministry of Education, Youth and Sports of the Czech Republic (Contract No. LM2018108). The design and construction of the gamma-ray calibration stations were funded by research grants by the European Space Agency (ESA)  (ESA ESTEC Contract No. 4000103891/11/NL/CBi).

Last update: January 2022