研究目的
Investigating the stability and transferability of the ultrastable low-noise current amplifier (ULCA) between two laboratories for precise current measurements.
研究成果
The ULCA trans-resistance gain ATR was stable at the 10-7 level during inter-laboratory transfers when the temperature did not drop below 15 °C. Measurements of 1 MΩ traceable to the QHR at NPL and PTB agreed within a relative combined uncertainty of ~6×10-8.
研究不足
The first transfer showed a relative change of ~6×10-7 in RIV, possibly due to the lower minimum temperature (12 °C) experienced by the ULCA during this transfer. The sensitivity of RIV to transportation effects was noted, with a shift of 1×10-7 observed when moving the unit between two laboratories at NPL.
