[time-nuts] Fw: Helium and MEMS oscillators don;t mix well

David Witten wittend at wwrinc.com
Thu Nov 1 17:08:35 EDT 2018


Ok, one last try:

>From AuntMinnie.com, free but subscrip[tion-based newslettter for clinical
radiologists and related staff:


November 1, 2018 -- A second imaging facility is reporting problems with
Apple devices that appear to be related to the operation of the center's
MRI scanner. Nearly 10 late-model Apple iPhones and Watches were
permanently disabled at a Delaware center after it ramped down its MRI
magnet.

CNMRI is an imaging facility in Dover, DE, that specializes in neurology
and sleep medicine. It operates a 1.5-tesla MRI magnet and also performs
studies such as polysomnography, nerve conduction, and home sleep studies,
according to Dr. Robert Varipapa, a neurologist at the center.

In mid-October, field service engineers from an imaging OEM arrived and
ramped the magnet down and then back up again. Immediately thereafter,
staff members at the center who owned Apple devices with wireless charging
reported that their devices were disabled. Approximately eight or nine
devices were affected, according to Varipapa.

Only newer-model Apple products such as the iPhone 8 and iPhone 10 were
affected, he added. Those with older models didn't experience any problems,
nor did staff with Android phones.

The Delaware center's experience is similar to that of an Illinois hospital
that also reported conflict
<https://www.auntminnie.com/index.aspx?sec=sup&sub=mri&pag=dis&ItemID=123398>s
between its MRI scanner and iPhones. That site reported that nearly 40
iPhones stopped working after the installation of a new MRI scanner. The
problem was attributed to helium gas that may have leaked during the
installation and found its way into the mechanical workings of the phones.

But there are also crucial differences between the Illinois incident and
the experience at the Delaware center. For one thing, the Delaware site
never experienced a helium leak, to Varipapa's knowledge. Also, while the
Illinois site reported problems with Apple models at the iPhone 6 level and
above, in Delaware the problem was restricted to newer models with wireless
charging -- no iPhone 6 devices were affected, Varipapa told AuntMinnie.com.

Finally, at the Illinois hospital, some of the iPhones began working again
after the helium inside the devices apparently dissipated. At CNMRI, all of
the smartphones were permanently disabled, and staff had to get new ones.

Varipapa said CNMRI's physicist told him that the center's experience is
not an uncommon one. The physicist has heard that some field service
engineers tell staff members to place smartphones in their cars' glove
boxes when MRI magnets are being serviced, he said.


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