Shielding Leica Hybrid detectors

[Andrew Vaughan-2]

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Hi,

Does anyone have any advice for shielding the Hybrid detectors on Leica confocal microscope systems? I'm having a real problem with what I assume are mobile phone signals, sometimes coming from the room next door to the confocal. I have signs up telling people to turn off their phones or put them in flight mode but people forget because everyone has their phone on all the time these days. Also I'm beginning to suspect there are other signals that cause the interference but I've no way of telling. I saw there was a thread about this a few years ago called 'tin foil hats.' I kind of feel like I'm getting a bit paranoid myself.

Thanks,

Andrew Vaughan.

[Michael Giacomelli]

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Hi Andrew,

What kind of interference do you see?  What kind of experiments are you
doing when you see it (pure confocal, photon counting)?

I haven't used the hybrid detectors, but I have spent a lot of time
worrying about interference in fast ordinary PMTs for FLIM.  In my
experience cell phones are usually not a huge problem because the frequency
is a little too high (>700MHz) and the transmission power is quite low,
although with a fast enough hybrid detector you might be able to catch the
lower LTE bands.  You can check with a spectrum analyzer if you have one.

The biggest problem I've found with FLIM measurements has been FM radio
pick up, since the transmission power is often very high, and the
relatively low frequency means that they are efficiently amplified if they
leak into the tube's bias voltage.  If you have a small amount of RF
leakage into the system, or if you are using an amplifier that is only
marginally stable, you may find that seemingly random things introduce
bursts of RF interference into the system (door opening next door, truck
drives by, etc).

Mike



On Fri, Jun 10, 2016 at 5:38 AM, Vaughan, Andrew <[hidden email]>
wrote:

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> *****
>
> Hi,
>
> Does anyone have any advice for shielding the Hybrid detectors on Leica
> confocal microscope systems? I'm having a real problem with what I assume
> are mobile phone signals, sometimes coming from the room next door to the
> confocal. I have signs up telling people to turn off their phones or put
> them in flight mode but people forget because everyone has their phone on
> all the time these days. Also I'm beginning to suspect there are other
> signals that cause the interference but I've no way of telling. I saw there
> was a thread about this a few years ago called 'tin foil hats.' I kind of
> feel like I'm getting a bit paranoid myself.
>
> Thanks,
>
> Andrew Vaughan.
>

[Massimiliano Garre']

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Hi Andrew,

as far as I know sensitivity to interferences depends a lot also on the
position of the HyD detector; i.e. internal Hyd in an inverted microscope
are quite protected from mobile interferences and only in-room devices
should be avoided. In case of an upright microscope a HyD detectore should
be  more exposed; same probably in case of external detectors.
We experienced a long period of sudden interferences leading to fully
saturated images and the Leica Tech staff changed piece by piece all the
elements of the HyD device. It didn't work, but finally they discovered the
problem was a thin wire suffering from a weak contact.
If you have the possibility to acquire few images during the interference
you could send them the the Leica assistance and they should be able to
understand if the problem is due to an ether interference or to a different
electrical source (HyD digital power supply and defective grounding could be
responsible as well).

Regards

Max


On Fri, 10 Jun 2016 09:38:17 +0000, Vaughan, Andrew
<[hidden email]> wrote:

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>*****
>
>Hi,
>
>Does anyone have any advice for shielding the Hybrid detectors on Leica
confocal microscope systems? I'm having a real problem with what I assume
are mobile phone signals, sometimes coming from the room next door to the
confocal. I have signs up telling people to turn off their phones or put
them in flight mode but people forget because everyone has their phone on
all the time these days. Also I'm beginning to suspect there are other
signals that cause the interference but I've no way of telling. I saw there
was a thread about this a few years ago called 'tin foil hats.' I kind of
feel like I'm getting a bit paranoid myself.
>
>Thanks,
>
>Andrew Vaughan.

[Straatman, Kees (Dr.)]

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Hi Andrew,

We had a lot of problems with horizontal interference blobs/lines in our images using the HyD detectors. For sure some came from mobile phones because if there was an open day and we had visitors in the analysis room next door we could see this on the screen and when somebody forgot to switch of their phone we saw the same problem. However, we had also a lot of interference when there was nobody else around. Besides that some days were fine and some days were not and one detector seemed worse than the other. Because this, and we had some additional problems with the system as well, we got a new HyD detectors and suddenly the problems were gone. So my feeling is that there is a difference between HyD detectors and maybe that older versions have more problems than newer versions?

Best wishes

Kees


Dr Ir K.R. Straatman
Senior Experimental Officer
Advanced Imaging Facility
Centre for Core Biotechnology Services
University of Leicester
http://www2.le.ac.uk/colleges/medbiopsych/facilities-and-services/cbs/lite/aif

-----Original Message-----
From: Confocal Microscopy List [mailto:[hidden email]] On Behalf Of Vaughan, Andrew
Sent: 10 June 2016 10:38
To: [hidden email]
Subject: Shielding Leica Hybrid detectors

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Hi,

Does anyone have any advice for shielding the Hybrid detectors on Leica confocal microscope systems? I'm having a real problem with what I assume are mobile phone signals, sometimes coming from the room next door to the confocal. I have signs up telling people to turn off their phones or put them in flight mode but people forget because everyone has their phone on all the time these days. Also I'm beginning to suspect there are other signals that cause the interference but I've no way of telling. I saw there was a thread about this a few years ago called 'tin foil hats.' I kind of feel like I'm getting a bit paranoid myself.

Thanks,

Andrew Vaughan.

[Steffen Dietzel]

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Andrew, Michael,

maybe the cell phones in the US use different frequencies, but we surely
saw cell-phone related artifacts with HyDs on our SP5: Stripes in the
images that went away when everybody in the room switched the cell
phones off.

The worst interference we ever saw actually came from a pump with
integrated WiFi hotspot, (which allowed set-up of the pump via a tablet
computer) that was used about 2-3 meters away from the HyDs on a
neighboring microscope. So possibly a WiFi router in the hallway may
also not be a good idea.

Andrew, have you tried whether a tin hat actually helps?  For short
tests aluminum foil should do, for long term you'd rather not want to
block air flow for cooling.

Steffen


Am 10.06.2016 um 18:07 schrieb Michael Giacomelli:

> *****
> To join, leave or search the confocal microscopy listserv, go to:
> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
> Post images on http://www.imgur.com and include the link in your posting.
> *****
>
> Hi Andrew,
>
> What kind of interference do you see?  What kind of experiments are you
> doing when you see it (pure confocal, photon counting)?
>
> I haven't used the hybrid detectors, but I have spent a lot of time
> worrying about interference in fast ordinary PMTs for FLIM.  In my
> experience cell phones are usually not a huge problem because the frequency
> is a little too high (>700MHz) and the transmission power is quite low,
> although with a fast enough hybrid detector you might be able to catch the
> lower LTE bands.  You can check with a spectrum analyzer if you have one.
>
> The biggest problem I've found with FLIM measurements has been FM radio
> pick up, since the transmission power is often very high, and the
> relatively low frequency means that they are efficiently amplified if they
> leak into the tube's bias voltage.  If you have a small amount of RF
> leakage into the system, or if you are using an amplifier that is only
> marginally stable, you may find that seemingly random things introduce
> bursts of RF interference into the system (door opening next door, truck
> drives by, etc).
>
> Mike
>
>
>
> On Fri, Jun 10, 2016 at 5:38 AM, Vaughan, Andrew <[hidden email]>
> wrote:
>
>> *****
>> To join, leave or search the confocal microscopy listserv, go to:
>> http://lists.umn.edu/cgi-bin/wa?A0=confocalmicroscopy
>> Post images on http://www.imgur.com and include the link in your posting.
>> *****
>>
>> Hi,
>>
>> Does anyone have any advice for shielding the Hybrid detectors on Leica
>> confocal microscope systems? I'm having a real problem with what I assume
>> are mobile phone signals, sometimes coming from the room next door to the
>> confocal. I have signs up telling people to turn off their phones or put
>> them in flight mode but people forget because everyone has their phone on
>> all the time these days. Also I'm beginning to suspect there are other
>> signals that cause the interference but I've no way of telling. I saw there
>> was a thread about this a few years ago called 'tin foil hats.' I kind of
>> feel like I'm getting a bit paranoid myself.
>>
>> Thanks,
>>
>> Andrew Vaughan.
>>

--
------------------------------------------------------------
Steffen Dietzel, PD Dr. rer. nat
Ludwig-Maximilians-Universität München
Biomedical Center (BMC)
Head of the Core Facility Bioimaging

Großhaderner Straße 9
D-82152 Planegg-Martinsried
Germany

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