Intermittency in a turbulent low temperature gaseous helium jet

We analyse experimental velocity measurements on the axis of a low temperat ure gaseous helium jet. From independent increments arguments, we reproduce the behaviour of structure functions. We show where this approach fails an d how the intermittency phenomenon is a small correction. The physical argu ments under the multiplicative cascade models for this intermittency imply an acceleration of this cascade close to the dissipative range, which we ar e able to evidence. This acceleration could be responsible of the apparent Extended Self Similarity between structure functions of various orders.