The VEPP-3 electron-positron storage ring


The VEPP-3 storage ring (perimeter: 74.4 m, injection energy: 350 MeV, maximal energy: 2000 MeV) was built in 1967-1971 and modernized in 1986-1987.

Main applications:

  • booster for the VEPP-4M collider;
  • synchrotron radiation production for users;
  • X-ray lithography and LIGA-technologies;
  • nuclear physics experiments using an internal gas target.

The experiments successfully finished:

  • generation of coherent optic radiation by the VEPP-3 electron beam ("Optic clystron");
  • gamma-quantum beam production by Compton back-scattering (ROKK-2 facility).

Electrons or positrons are injected from the "Positron" injector with 1 Hz rate. Maximal stored electron beam current is 500 mA, storage rate is 2-5 mA/min. Maximal electron beam current accelerated up to 2 GeV is 160 mA, acceleration time is about 4 min. Maximal stored positron beam current is 50 mA, storage rate is 0.04 mA/min.

The VEPP-3 layout in the PDF format is  here.

Design lattice functions in the PDF format are  here.

Main parameters

Perimeter74.39 m
Revolution frequency4030.0 kHz
Beam energy

0.35 GeV
1.80 GeV
2.00 GeV
Momentum compaction factor0.071
Betatron tunes, horizontal/vertical5.10/5.20
Damping factor, horizontal/vertical/longitudinal 0.93/1.00/2.07
Admittance, horizontal/vertical138/26 mm·mrad
Aperture in semi-rings55x24 mm2
Accelerating RF system 8 72
Frequency8.06 MHz72.54 MHz
Harmonic number218
Number of cavities11
Maximal amplitude voltage per cavity20 kV800 kV
Maximal RF generator power20 kW150 kW
Cavity transit factor 0.85
Design beam parameters E = 350 MeV E = 2000 MeV
Damping time of
  ver. betatron oscillation
  hor. betatron oscillation
  phase oscillation

820 ms
870 ms
390 ms

4.0 ms
4.3 ms
2.0 ms
Horizontal emittance0.009 mm·mrad0.292 mm·mrad
Beam size (betax=betay=5.5 m, D=1.2 m)
  hor. betatron
  hor. phase
  hor. total
  ver. (at 10% coupling)

0.225 mm
0.150 mm
0.270 mm
0.027 mm

1.270 mm
0.870 mm
1.540 mm
0.154 mm
Energy spread dE/E, r.m.s.0.0125 %0.072 %
Bunch length, r.m.s.23.5 cm9.1 cm
Energy loss per turn0.21 keV246 keV (with wiggler)
Synchronous phase174.9°150.4°
Synchrotron tune0.0004 (1.77 kHz)0.0066 (26.7 kHz)
Separatrix width
  dXsep (D=1.2m)

6.33 mm

30 -220°
7.71 mm
Beam life time0.5-1.0 hour4-6 hour