Pictorial tour of the Fermilab 400 MeV Linac

The Linac Group exists in the Accelerator Division within the Proton Source Department. We take gaseous hydrogen from a little bottle, inject it into the ion source, make negatively-charged hydrogen ions and extract them from the source at about 18,000 electron volts (18 keV). The rest of the acceleration goes like this:

C-W
Pre-accelerator
Electrostatic accleration down the 750 kV potential difference to ground for a final kinetic energy of about 750 keV;
750 keV
Transfer Line
One transfer line is 10 meters long (H- line, "H-minus"), the other is 4 m long (I- line, "Eye-minus");
201 MHz
Drift Tube Linac
Accelerated in a 201.249 MHz drift-tube linac, though five large tanks, to 116 MeV; (This is a shot of the inside of Tank 2, which is, of course, normally closed up and under vacuum. The drift tubes, with the holes in the middle, are prominant. Also visible is a pumping port at the bottom, and the bulk tuner which emerges from lower left.)
Transition Section
No picture available
Compressed through a 4 m rf transition section to match the 201 MHz beam into the 805 MHz rf structure, and change the transverse focussing
805 MHz
Side-coupled Cavity
Linac
And finally through seven 804.996 MHz side-coupled cavity structures to the final energy of 401.5 MeV.


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