Model SMM 770 Scanning Magnetic Microscope System
TRISTAN TECHNOLOGIES --Page
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Because of the local environmental noise (even inside a mu-metal shield), these
measurements show different noise levels than the results shown in Figure 3-3. It should be
noted that HTS SQUID sensors typically show a 10 - 30% variation from device to device.
Table 3-2 and
Table 3-2
summarize the main system’s parameters and SQUID performance
using a Tristan Technologies, Inc. iMC-303 iMAG
®
SQUID Controller.
Table 1 System Parameters
IFL-301-H S/N
2020
SQUID Mi10803
Channel 1
Gain X100
Slew Normal
Heat Time (1k R)
2 sec
Cool Time
99 sec
Triangle Amplitude
1.65 V
p-p
Bias% 35
Bias% 35
Mod% 12
Skew 18
Table 3-2:
SQUID performance tested with
iMAG
®
Gain
Slew
X100
Normal
x100
Slow
X50
Normal
Units
V/
Φ
o
0.95
0.95
Noise @5kHz
9.15
pT/
√
Hz
Bandwidth 22
kHz
Loop Locked
yes
yes
yes
Note – gains 1-50 are done with one feedback resistor and gains 100-500 are done with a different
feedback resistor. The Gain X100 and X50 have the same analog gain so that will have to be
manually accounted for when measuring data not through the software.
3.3.3 System Noise
The following spectra were taken of the complete SMM 770 system.
