Diagnostics

Diagnostic methods are used to get proper information on beam and possibly looping them into a feedback

Another current transformer is placed before SCDTL-1 entrance. 48 windings are wounded across a Vitrovac 1 cm inner diameter core and all the device is under vacuum.

A current transformer is also placed after each SCDTL structure. here a break is introduced in the vacuum pipe and the CT is in air.

Ad hoc amplifiers are used to increase the output voltage since the typical 1V/A natural sensitivity of the CT and the very low beam pulse current (200 - 1 uA) give rise to very low signals.

Scintillation screens and triggered Basler cameras are used to check the beam in air after 50 um Kapton window. Mainly beam center is evaluated and alignment of PMQs, or structure or EMQ is performed after these images.

Proton beam current is monitored by an amplified current transformers

Injector toroid is provided by the injector seller AccSys.and has a 2mA/V sensitivity. Other toroids are made by Bergoz and some in-house.

As an example, on the left this measurements are reported for the injector beam as function of DTL RF power, parametrized with EDTL variable used by the injector control system.

An analysis of these curves allow also to infer the Energy distribution of the beam.

Faraday cups are used to check current at the beam exit windows. These are generally made of 50 um Kapton foils.

For measuring beam energy several current measurements are taken by interposing in air, between foil and cup, a succession of pure aluminum thin calibrated sheets in order to check transmission versus aluminum thickness. .