24/10/2015Sheffield University 1 Target Electronics Recap - Decision has been made to rebuild the target electronics control system so that it is upgraded from being an expert system to fully turn-key. Fundamentally the aim is to have a system that can be fully controlled via a PC interface and will fit into the MICE EPICs framework. We are going to use a FPGA board that was designed at Imperial to be a general purpose controller. Plenty of I/O for control purposes and a USB interface to provide the link for soft control / DAQ. 4 USB DAQ PCB boards have been manufactured and there are now (at least) 2 fully functional USB DAQ boards. One is now at Sheffield and the others are at Imperial. Software Drivers for the PC side of the USB interface and the VHDL code to run the USB chip on the USB DAQ board have already been written and tested. These were provided by Matt Noy.

24/10/2015Sheffield University 2 USBDAQ USB Mini- B 1.2V Regulator 2.5/3.3V Regulator Cypress SX2 USB Interface Differential / Single Ended User IO Single Ended User IO 1M Gate Spartan 3 FPGA 4Mb PROM

24/10/2015Sheffield University 3 Target Electronics James Leaver is using these drivers to create the software that will run the PC/board interface. Communication between the board and a host PC has now been established. Paul Smith is currently learning VHDL so that a replica (with improvements!) of the digital components in the present target electronics can be synthesised onto the FPGA. It is expected to be a couple more weeks before he is in a position to start translating the current target hardware over to the FPGA. There will be a requirement for several analogue boards to be interfaced to the USB DAQ board. Some of these boards will represent upgrades to the analogue electronics currently operating in the target controller and there is the possibility that it may be possible to establish the complete target DAQ through the FPGA board and USB interface. All these boards will need designing from scratch as current boards are incompatible with the USB DAQ.

24/10/2015Sheffield University 4 Planning Once P. Smith is in a better position to appraise the details of how the current hardware can be synthesised onto the FPGA a more formal and detailed plan will be drawn up between James and Paul outlining both the stages of the upgrade process and the intended improvements to the target control system. Broadly speaking the process can be broken down into: –Synthesize current digital system (effectively replicating its current function). –Ensure that the replicated system can be fully controlled via a GUI interface and establish bi-directional data flow to the controller. –Create Daughter boards for Analogue IO. –Integrate Target DAQ (if possible) - will require additional daughter boards. –Add a standalone interface to USB DAQ board so it can be fully controlled independently of the host PC.

24/10/2015Sheffield University 5 Target Shaft Lengthening In redesigning the target support and shaft the target shaft has been effectively moved 10mm further into the beampipe. This has been done to increase the depth to which the target can penetrate the ISIS beam, thereby giving the opportunity to increase the beamloss that the target produces for MICE. However the consequence of this is that the target now will sit10mm further into the beampipe when it is not being actuated; effectively it will sit 18 mm below the top of the beampipe in ‘hold’ mode. (The current limit on the travel of the target will not allow the target to be levitated any higher than this as the allowable travel has not been changed from the last target) It is not known whether the change in the targets hold position will cause problems with the target scraping the ISIS beam at injection as it has not yet been possible to profile the beam cross section at injection at the location of the target.

24/10/2015Sheffield University 6 Target Shaft Lengthening If the beam does scrape the target at injection and ISIS consider this as being problematic then the target’s hold (levitated) position can be raised to the position that the previous target was held at by altering the stops on the target frame. If this is necessary then the maximum beamloss produced by the target will then be limited to the levels that have been observed over the past year’s running. If beam scraping at ISIS injection is a problem but it is shown that the target needs to penetrate further into the ISIS beam then the solution will be to extend the travel of the target mechanism. However this is a MAJOR upgrade.