We study the 4–200 keV spectral and temporal behaviour of the low mass X-ray binary 4U 1820–30 with INTEGRAL during 2003–2005 .
This source as been observed in both the soft ( banana ) and hard ( island ) spectral states .
A high energy tail , above 50 keV , in the hard state has been observed for the first time .
This places the source in the category of X-ray bursters showing high-energy emission .
The tail can be modeled as a soft power law component , with the photon index of \simeq 2.4 , on top of thermal Comptonization emission from a plasma with the electron temperature of kT _ { e } \simeq 6 keV and optical depth of \tau \simeq 4 .
Alternatively , but at a lower goodness of the fit , the hard-state broad band spectrum can be accounted for by emission from a hybrid , thermal-nonthermal , plasma .
During this monitoring the source spent most of the time in the soft state , usual for this source , and the \gtrsim 4 keV spectra are represented by thermal Comptonization with kT _ { e } \simeq 3 keV and \tau \simeq 6 –7 .