Deva user manual - ISIS

More documents

Recommendations

Info

$Single Crystal Diffraction: Shelx tutorial - ISIS$

DEVA Manual 26 9. Troubleshooting If you have to reset any equipment as described below, remember to tell your local contact as soon as possible – it may indicate that something is about to fail completely or needs repairing. 9.1. No muons (or far fewer than expected) First check: • The Frame Start light on the DTU module in the DASH2 TDC rack is lit - if not, the beam is off or there is no start pulse from the Cerenkov detector. Frame Start flashing means ISIS is at base rate (1/32 of 50Hz). • If Frame Start is present, is the computer reading back from the electronics? Type SHOW RUN • Is there any beam going to the other muon instruments? 9.1.1. Beam Off Check the proton beam current – the big display in the hall or the ISIS PPP Monitor program on the PC. The last hour graph on the ISIS web page only updates every 10 minutes. 9.1.2. Kicker The racks in the kicker control area (down the steps behind EMU) are: Momentum slit (do not touch) Beam slits for each instrument HV for Cerenkov (start pulse) detectors Kicker HV supply Kicker monitor scope Old UPPSET unit (not in use) Kicker main control panel Thyratron Separator HV supply If the kicker trips off, DEVA and EMU have no beam and MUSR will have a double pulse with twice the usual rate. Some lights will be lit on the control panel but the HV supply will be off. Instructions for resetting it are attached. Check with the other users before doing anything. The kicker status is indicated in the MCR – someone from the crew may reset it. 9.1.3. Beamline Magnets When one of these trips the beam may be lost completely or just reduce in rate and have a huge spot size. Magnets Q1-Q9, B1/2 and the Separator are common to all three beamlines. B1/2 goes off if any of the Muon Beam Off buttons are pressed, and the white lights will come on in all the areas. Warning: it is possible to press a button gently (accidentally) without it latching in yet trip the beam. Septum A and Q10A-Q12A are for the DEVA branch only. B is MUSR, C is EMU. The Switchyard magnets are normally off . The magnet supplies are located on the platform at the far end of the hall. Each position is labelled with the required current for that magnet. Reset1 Separat Q4 Q8 DEVA DEVA EMU Reset2 Q10A spare Q10C Q2 Q6 Q9 Helm- Septum Septum Q11A Q11B Q11C Q1 on/off on/off on/off holtz A C PLC on/off on/off on/off Q3/5 Q7 B1/2 Q12A Q10B Q12C spares spares spare SWY1 SWY2 Reset1: interlocks with reset buttons for Q1-Q9, B1/2 and the Separator supplies Reset2: interlock reset buttons for Q10A-Q12C, Septum, Switchyard and instrument magnets.
DEVA Manual 27 on/off: panel with ON and OFF buttons for the power supplies. spare: Spare supplies, not connected or powered up. (ISIS staff use only!) The PLC has status lights for the second group of magnets and for the shutters: the upper row of modules show inputs from various sensors and switches and the lower row is the outputs to enable the supplies. For interlocks the general rule is Lights ON = good, lights OFF = tripped. Farnell supplies: press the interlock reset buttons then the green ON button next to the power supply. It should not be necessary to touch the controls on the supply itself. Check it returns to the setpoint and the green “Output Enable” light is on. Danfysik supplies (septum): press the interlock reset buttons, then on the supply itself press OFF/Reset and then ON. Check the setpoint and readback values. The Separator electric field is provided by the Glassman unit in the rack next to the kicker. The usual value is 90kV. 9.1.4. Photomultipliers These are powered from the Lecroy HV supply in the cabin. Turn all channels on or off with the HV ON and HV OFF buttons. The Cerenkov start counter is supplied from the HV supply next to the slit controls – check the other instruments are counting data OK. 9.1.5. Beamline Vacuum This is monitored on the rack on the platform, above the target/kicker control area. Check that the vacuum in the beamlines is OK (about 10 -6 mbar or better) and that all the valves are open except for those labelled “vent” and “bypass”. The “line” valve in each branch of the beamline is linked to that instrument’s shutter. Do not attempt to open or close valves – ask your local contact or the MCR for advice. 9.1.6. RF triggering Is the data acquisition being triggered from the RF zero crossing – if so is it working properly? 9.1.7. Computer There may be muons but the computer is not reading back from the electronics. See below. 9.1.8. Blocker Closed ? The blue lights in the area will light if the blocker has been opened correctly. 9.2. Strange data 9.2.1. Light leaks On an asymmetry vs. time plot this gives asymmetry going to +100% or –100% at later times. If a detector develops a light leak (large background number of counts in the later time bins) turn its voltage off to prevent damage. 9.2.2. Beamline Magnets If a beamline magnet trips there may still be muons but the spot size could be huge and the asymmetry change to an implausible value. Reset it as above.
Page 1 and 2: DEVA Manual 1 DEVA User Guide J.S.
Page 3 and 4: DEVA Manual 3 1. Getting Started Th
Page 5 and 6: DEVA Manual 5 Profiles taken from t
Page 7 and 8: DEVA Manual 7 32 17 31 30 15 16 14
Page 9 and 10: DEVA Manual 9 2.8. Muon stopping ra
Page 11 and 12: DEVA Manual 11 This cryostat can us
Page 13 and 14: DEVA Manual 13 If the cryostat is s
Page 15 and 16: DEVA Manual 15 5. Data Acquisition
Page 17 and 18: DEVA Manual 17 Select from the menu
Page 19 and 20: DEVA Manual 19 6.4. Taking your dat
Page 21 and 22: DEVA Manual 21 previous cycle and s
Page 23 and 24: DEVA Manual 23 8. RF and other spec
Page 25: DEVA Manual 25 8.2.5. Setting up To
Page 29 and 30: DEVA Manual 29 • Set point too la
Page 31: DEVA Manual 31 10.3. Transport Trai

Deva user manual - ISIS

Create successful ePaper yourself

Delete template?

Save as template?