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Target Status Report

Target Status Report. Lara Howlett University of Sheffield. Contents. A look at the specs Reminder of Prototype plans Meetings with ISIS engineers Testbeam plans Status of electronics, readout and radiation studies Plans / Timescale. Updated Specs.

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Target Status Report

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  1. Target Status Report Lara Howlett University of Sheffield

  2. Contents • A look at the specs • Reminder of Prototype plans • Meetings with ISIS engineers • Testbeam plans • Status of electronics, readout and radiation studies • Plans / Timescale

  3. Updated Specs • Frequency 1-3 Hz. Higher may be possible but we may be limited by heating • Target will dip into the beam by 5-10mm • Only the intersection of the beam in the last 1ms is useful • We wish to intersect as little beam that is not useful as possible

  4. Updated Specs 2.05ms 4.4mm

  5. Updated Specs 2.75ms 7.4mm

  6. Updated specs 3.35ms 9.8mm

  7. Overview of Prototype • The prototype is currently being built and is expected to be ready by the end of the month • The design consists of a a magnetic shuttle to which the target rod is attached • This sits inside a series of coils which are driven in 3 phase

  8. Prototype ~8 cm

  9. Target Mechanism

  10. Meetings with ISIS • Several very useful meetings have taken place with engineers from ISIS • These have been very useful for beginning to look at • Safety issues • Vacuum issues • How the target mechanism will be mounted • A first set of engineering drawings have also been produced by Stephanie Yang

  11. Outcomes • The diaphragm springs will most likely be replaced by ceramic bearings • The target will be mounted on a replacement for the current A frame to reduce vibrations transmitted to the beam pipe by the target • The possibility of replacing the inductive measurement system with an optical system is under investigation • The possibility of mounting the target using nested bellows with a gate valve which would allow the target to be completely removed from the beam in case of failure is being investigated

  12. Schematic

  13. Status of Electronics • The electronics consists of two separate integrated circuits • Control logic • Current controller

  14. Control Logic Position Decoder/Switching Sequencer OpticalIsolators Hex-Bridge Electronic 3 Phase Motor Switch (6 MOSFETS) Hall Switches (Position Sensors) ACTUATOR

  15. Current Controller Active Current Control Position Decoder/Switching Sequencer PWM @ 19.5 kHz User Set Current (8-Bit Resolution) Current Transducer Hex-Bridge Electronic 3 Phase Motor Switch (6 MOSFETS)

  16. Future Plans • To test this prototype circuitry with the actuator in order to ascertain its performance • Development of a quadrature position sensing system (to replace the hall switches) – This will allow greater control of the switching due to improved position information. • To develop an interface that will allow the electronics to be controlled via a PC

  17. Radiation Studies • Simulations of radiation levels have continued • These now include the geometry of the target mechanism • Radiation levels in the magnet are extremely high

  18. Radiation studies Units : Grays/year/ Unit Density

  19. Status of Readout • Problems with the readout board were experienced which caused jumps in the counts which were read out • After long correspondance with the company who provided the board, and returning the board for tests twice the problem has been resolved • The readout system will therefore be ready to be used with the new prototype when it arrives • Sheffield will have a summer student who will be working on this in the coming months

  20. Test Beam Plans • There are plans to have the prototype ready for a test operation by December • This would involve intersecting a few ISIS beam pulses when the machine starts up in January • Measurements from the scintillators of the Glasgow group will hopefully allow us to gain a better understanding of how far into the beam we need to go and how the beam profile changes with distance

  21. Backup plans • In parallel with the work described two ‘backup’ plans are being investigated in the background • The use of a lever to move the actuator away from the target • The use of a cam to provide the motion

  22. Lever • Despite the hope that a lever would provide a mechanical advantage discussions with an engineer indicate that because of the low mass of the shuttle this is not possible • However the use of a lever would give the advantage of moving the electronics and magnets away from the radiation if this is necessary • The other advantage of this arrangement is that the target mechanism is isolated from the ISIS vacuum eliminating any possible problems of contamination

  23. Cam • The idea of a cam has also been investigated in the background so that in the instance that the em design does not produce the accelerations required a backup plan is in place. This would be used in conjunction with a lever

  24. Plans • Upcoming milestones: • Prototype should be assembled and ready for tests to begin mid July • Prototype should be sufficiently tested to put in the beam by Christmas • Data from beam tests should be used as input for final design

  25. Conclusions • Work towards the prototype is progressing and we expect to start tests in the coming weeks • Several successful meetings with ISIS engineers have taken place and these have been extremely useful in progressing with the design • Exactly how far we need to go into the beam has significant implications for the design, so we should pin this number down as much as we can

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