Re: [AMMRL] AMMRL: Diverging behavior detected during shimming (Profile changed)

From: Spin-Doc <bert.heise_at_spin-doc.net>
Date: Wed, 5 Aug 2026 20:55:08 +0200
Hi,

Just a mini addition to Ken‘s question:
It doesn’t look like a (mechanically) shifted shim coil to me - this should induce
a pronouced asymmetry in the PFG profile (narrower on only one side). Your case looks more like a
change in the parameter-value-to-true-G/cm calibration, leading to a slightly lower gradient
strength than expected/previously, resulting in a generally narrower and taller profile.

Not completely impossible though that the PFG amp output has decreased a bit though - was it
maybe particularly warm in your lab? Some local labs here (yes, in Germany…) unfortunately
aren’t equipped with air conditioning, leading to lall kinds of interesting issues…

Cheers
Bert

-> Sent via mobile <-

Spin-Doc 
Magnetic resonance equipment, service, training & more
Dr. rer. nat. Bert Heise
Owner, applications scientist
Kiefernweg 13
58239 Schwerte
Germany
Mail: bert.heise_at_spin-doc.net
Phone: +49-171-5135315

Representing MestreLab software, Stelar relaxometers & Barthel HF amplifiers


_._,_._,_
Groups.io Links:

You receive all messages sent to this group.

View/Reply Onl= ine (#3660) | Reply to Group | Reply to Sender | Mute This Topic | New Topic
Your Subscription | Contact Group Owner |

_._,_._,_
Received on Wed Aug 05 2026 - 12:12:01 MST

This archive was generated by hypermail 2.4.0 : Tue Sep 01 2026 - 13:53:27 MST