7T general info & troubleshooting

Overview page for 7T related information

General safety aspects

• differences with 3T

Useful commands at console

(might move to separate page accessible to all users)

• permproc stop|start all stop|start all processes (NB including data transfer!).
• start_stop_procs.pl stop also stops background processes. Needed in case of hardware reset in service room.
• Communication with PRIDE (e.g. for image-based shimming): PrideXS_XML. In case of error Access denied, no SW key pressed, kill process pridexsproc_win_cs.exe in Task Manager.
• Export raw data: use gt pack 'n go utility
• Location shim parameters: E:\Export\PRIDE\shimtool\linear_shim.txt

Changed default settings

• Control parameter Reconstruction: Noise clip factor 1,2,3: 0.001. Avoids noise clipping of phase to -pi in case the SNR is too low.
• Increased maximum average power to 20: max_avg_pow: 20 in mpgcoil_mtx_tr.i, add file to patch folder to apply.

Power off and power on sequence(s)

CDAS

• Reset CDAS: turn off green switch. Wait 5 seconds. Turn red switch. Wait 5 seconds. Turn on in reverse order.

Main System

• Power off sequence: 1. scan computer. 2. CDAS. 3 Power gradient (right) and System (left), see Leiden document (original in scstaff)
• Power on sequence: in reverse order

Compressors

Procedure testing/resetting compressors Helium pump: 2 small cubic devices in the far right corner. The green light on the left device should be flashing. Check messages on small LED-displays: scroll with arrow up/down buttons. Should all be OK, not ERR. Temperature of tubes should be below room temperature (i.e. cold). To reset: press OFF. You should hear it switching off. Wait, and press ON, again hearing it switching on. To hard reset: Press OFF. Wait. Turn small black switch from I to O. Wait. Turn back to I. Wait. Important: press ON to turn the compressor back on.

Common malfunctions

• table
• coldhead compressors
• gradient amplifiers

Philips contacts (?)

Cor Romijn Anton ? Merel ?