Subject: Re: attaching Brandeis sensors
Date: Wed, 23 Mar 2005 16:49:46 -0800 (Pacific Standard Time)
From: Paul Mockett 
To: Kevan Hashemi 

Hi Kevan,

All three sensors indicated a small shift to lower temperature.
However they shifts were small and could be due to systematics. The
worst case where both glues were used a shift of only 0.07 degree was

We have some concerns about the possible affects of glue touching the
lead wires of the PT1000 temperature sensors from Brandeis. Glue can
vary in its conductivity depending on humidity, temperature, mixing
procedure and expiration date.

We were concerned about what appeared to be a few low readings we
observed. There appeared to be a possible 1.6 degree drop on one of
the BMC chambers and a 0.5 degree drop on a UW chamber. Subsequently
we tested three sensors by looking at their calibration change after
dousing the leads and sensor with glue. On one sensor we used super
glue (cyanoacrylate), a second DP460, and a third both glues. The
change in all three was a drop in temperature but very small, less
than 0.1 degree in the worst case of both glues used. But to be
cautious we adopted the following procedure.

We attach the sensor with super glue but are careful to keep the glue
away from the leads. We next cover the lead region with a narrow piece
of Mylar tape with acrylic adhesive. The sensor and tape are then
covered with DP460 being careful to not force glue under the Mylar

We tested the tape adhesive on a 2 cm pair of bare wires spaced ~1mm
apart. A resistance of greater than 10**10 Ωs was observed.

Cheers, Paul