VdG accelerator laboratory IEAP CTU


The laboratory of the Van de Graaff accelerator is devoted to basic research in experimental nuclear physics, as well as activities related to the development and testing of radiation detectors and the application of analytical methods in other areas (high-energy physics, materials analysis). The laboratory is part of the Institute of Experimental and Applied Physics (UTEF) of the Czech Technical University (CTU) in Prague. The facility serves as tunable source of heavy charged particles (light ions) and quasi-monochromatic fast neutrons. Most of the activity is related to experiments with charged particles (p,d,α) and fast neutrons (from D-T and D-D reactions). In addition to the accelerator, the laboratory houses two stations of discrete gamma rays (listed 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).



Light ion beams & neutron sources

Continuous beams are provided as follows. Light ions can be provided also as secondary scattered beams with intensity of order 10^5/cm^2/s. The neutron sources are equipped with active neutron monitors (liquid scintillator NE 213, 3He Bonner sphere) with online display and evaluation.

light ions   fast 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.



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.


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

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 system for spin physics (polarized beam + polarized target)
  • Cryogenic system for ultra-cold experiments (20 mK)


The team of the laboratory is:

● Michael Solar (administrator) ● Petr Masek (DAQ, radiation monitors, experiments) ● Jan Svejda (accelerator operator) 
● Jaroslav Smejkal (scientific head, physics experiments)   ● Zdenek Kohout (experiments, tagged neutrons) ● Jaroslav Cerny (beam guide operator) 
● Stanislav Pospisil (former director of IEAP CTU)  ● Tomas Slavicek (ESA gamma-ray stations)  ● Jaroslav Petrik (accelerator/beam guide support)
● Ivan Wilhelm (external adviser - polarization experiment)  ● Jan Broulim (Gamma-gamma coincidence system)  


Beam schedule & Contact

Beam/source time schedule: 2019

User/beam time form.

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

Visitors and interested users can contact:


Direct research and primary results obtained at the VdG facility

  • Peltola T., Wu X., Kalliopuska J., Granja C., Jakubek J., Jakubek M., et al., "Characterization of Thin p-on-p Radiation Detectors with Active Edges" Nuclear Inst. and Methods A 813 (2016) 139-146.
  • Ulyanov A., Morris O., Hanlon L., Granja C., et al. „Performance of a monolithic LaBr3:Ce crystal coupled to an array of silicon photomultipliers“, Nucl. Instr. Meth. A 810 (2016) 107-119.
  • C. Granja, M. Solar, S. Pospisil, A. Owens, I. Wilhelm, Z. Kohout, P. Masek, J. Svejda, J. Cerny, J. Petrik: "Basic and applied research with tunable mono-energetic neutrons at Prague Van-de-Graaff accelerator ", Proc. XII Int. Topical Meeting on Nuclear Applications of Accelerators (AccApp 2015), American Nuclear Soc. (2016) in print
  • Granja C., Slavicek T., Kroupa M., Owens A., Pospisil S., et al., “Transportable Source of Gamma Rays with Discrete Energies and Wide Range for Calibration and on-site Testing of Gamma-Ray Detectors”, Nucl. Instr. and Methods A 771 (2015) 1–9
  • Jancar A., Kopecky Z., Dressler J., Veskrna M., Matej Z., Granja C., Solar M., “Pulse-Shape Discrimination of the New Plastic Scintillators in Neutron-Gamma Mixed Field Using Fast Digitizer Card”, Rad. Phys. Chemistry (2015) in print (doi:10.1016/j.radphyschem.2015.05.007)
  • F. Lehar, E. A. Strokovsky, C. Wilkins: Experimental Physics with Polarized protons, Neutrons and Deuterons, Textbook, Publisher Czech Tech. University (2015)
  • C. Granja, V. Kraus, S. Pospisil, V. Pugatch, V. Kyva, A. Okhrymenko, M. Pugatch, D. Storozhyk, Position-Sensitive Coincidence Detection of Nuclear Reaction Products with Configurable Array of Timepix Detectors, Proc. X L.A. Symp. Nucl. Phys. & Applications, Proc. of Science PoS (2014) 043.
  • J. Cernak, G. Helgesen, A.T. Skjeltorp, J. Kováč, J. Voltr, E. Čižmár: Magnetic properties of carbon nanodisk and nanocone powders, Physical Review B 87 (2013) 87.
  • Granja C., Kralík M., Kohout Z., Masek P., Pospisil S., Solar M., Šolc J., Vykydal Z., Owens A., Vacík J., Tomandl I., Chvatil D., Bem P., Krist P., Stursa J., Rypar V., "Neutron Sources for Test and Calibration of Neutron Detectors for Space Research", Amer. Inst. of Physics (AIP) Conf. Proc. 1423 (2012) 446-452.
  • Kroupa M., Granja C., Janout Z., Kralik M., Krejci F., Owens A., Pospisil S., Quarati F., Solc J., Vobecky M., "Wide Energy Range Gamma-Ray Calibration Source", J. of Instrumentation JINST 6 (2011) T11002.


Partial research and secondary results obtained at the VdG facility

  • C. Granja, S. Polansky, Z. Vykydal, S. Pospisil, A. Owens, K. Mellab, Z. Kozacek, M. Simcak: “The SATRAM Timepix spacecraft payload in open space on board the Proba-V satellite for wide range radiation monitoring in LEO orbit”, Planetary and Space Science (2016) in printhttp://dx.doi.org/10.1016/j.pss.2016.03.009
  • C. Granja, S. Pospisil, Quantum dosimetry and online visualization of X-ray and charged particle radiation in commercial aircraft at operational flight altitudes with the pixel detector Timepix, Adv. Space Research 54 (2014) 241-251.
  • X. Wu, J. Kalliopuska, M. Jakubek, J. Jakubek, A. Gadda and S. Eranen, Study of Edgeless Radiation Detector with 3D Spatial Mapping Technique, J. of Instrumentation JINST 9 (2014) C04004.
  • B. Hartmann, C. Granja, J. Jakubek, O. Jaekel, S. Pospisil, M. Martisikova, Ion fragmentation study in ion beam therapy based on particle track recognition with pixel detector Timepix and compact setup, Int. J. of Particle therapy IJPT (2014) in print


The accelerator and the laboratory are operated and upgraded thanks to the research funding grant "VdG Research infrastructure" by the Ministry of Education, Youth and Sports of the Czech Republic. The design and construction of the gamma-ray calibration stations were funded by research grants by the European Space Agency (ESA).