DTL1 conditioning starts

The Drift Tube Linac (DTL) section of the ESS linac will accelerate the proton beam from 3.6 to 90 MeV,
that is about 40% of the speed of light. When fully operational, it will be the most powerful drift tube
linac in the world.

The copper drift tubes inside DTL1 (Image: F. Grespan/INFN)

The drift tube linac is a sequence of accelerating gaps, allowing protons to gain energy each time they
pass through a gap. The gaps are alternated with tubes, where the particles are shielded from the RF
field, and they simply drift. This is why it is called a drift tube linac.
Why do we want the beam to drift inside the tubes?
Because the RF field periodically reverses its polarity, and we need to make sure that the beam meets
the field always at the polarity giving acceleration.
The five DTL tanks are an in-kind contribution of INFN to ESS. Designed by INFN-Legnaro and INFN-
Torino, all the parts are produced and separately tested in Italy. Then everything is shipped to ESS and
assembled and tuned by INFN staff in a dedicated workshop located in the G02 gallery.

The DTL workshop at ESS (Image: F. Grespan/INFN)

After all the checks have been passed, it is time to inject “RF fuel” in the engine, starting the conditioning and then beam commissioning, to test the design performances. The first tank, DTL1 is now starting this last phase.INFN is involved with ESS in all stages of the DTL, from design to installation, from RF conditioning until beam commissioning. I must say that the collaboration is fantastic, with teams working very enthusiastically together on many fields!

The DTL1 installed in the tunnel (Image: F. Grespan/INFN)