Transfer-Channel Unilac-SIS18 Chopper (TK7-Chopper)

Description

Background

A chopper in the the transfer channel from Unilac to SIS18 cuts, from the rather Long Unilac puls, the portion which will be injected into the SIS18. The chopper acts by an electrostatic field on the ion beam: An adjustable High Voltage pulse is applied which deflects the beam into the SIS18 injection. Puls length and pulse position have to be adjustable (pulse Position must correspond to the trailing edge of the SIS18 injection bumpers).

Beeing in operation for more than 25 years, the exisitng chopper power supply will be replaced in the SIS18 shutdown period 2015/2016. In addition, the pulse shaping trigger unit will be replaced too.

Hardware Interface

The interface to the control system will not be compatible to the Interface of the existing chopper. While the proposed new interface will provide similar functionality as the existing one, in several aspects it will differ.

Some characteristics of the proposed new interface:

• Interfacing will be by SCU-Bus slave cards in a SCU unit
• Standard digital I/O and ADDA-cards will be used
• The chopper puls will be definied by a pulse which is generated by an digital I/O card.
• The SCU-Bus slave Cards, in combination with FE control Software, will support some exception logig, as follows
  • Limit the chopper pulslength in case a profile grid is inserted in the beam path behind the chopper
    • Information whether a profiler grid is inserted will be provided by cable to one input in the SCU-Bus digitial I/O slave card.
  • The chopper puls must be terminated immediately when a spark in the SIS18 injection Septum is detected.
    • Information when a sparc occured is provided by cable to one input in the SCU-Bus digitial I/O slave card.
• Standard (general) SCU-Bus slave cards will be used, no components which are specific for the chopper will be foreseen.
• General means in the standard SCU-Bus slave cards will be forseen to support the exception logig, as listed above.
  • Implementation of the specific functionality of the exception logig will be by configuration of the cards only
  • no chopper-specific implementation in the SCU-Bus slave card hardware is foreseen

Property Layout

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