NMR/MRI
GaAsFET Preamplifiers

For over fifteen years, Advanced Receiver Research has produced low noise figure Gallium Arsenide amplifiers for nuclear magnetic resonance/magnetic resonance imaging applications. These amplifiers are an outgrowth of our standard receive only preamplifier product line that have been optimized for this application. Careful lot selection and screening of the GaAsFET devices has proven to be an essential process in delivering these low noise figure amplifiers - especially at the lower frequencies. Recently, we have added low magnetic versions (referred to as low mag) for many of the frequency ranges. In the low mag versions the powdered iron and ferrite cores are replaced with suitable air wound equivalent parts making these preamplifiers suitable for placement closer to or within the magnet. Supply voltage: 8 - 28 Vdc regulated. Current consumption: 25 mA. Connectors: BNC standard with certain other types available. Price: standard nmr/mri $157.45; low mag nmr/mri $167.45. Delivery: 1 week or less. Listed below are some of the frequency ranges for which we have built preamplifiers. If you don’t see exactly what you need please call as chances are good we can supply you with a custom preamplifier.

Center Frequency

2.3
3.3
4.2
6.2
8
8.5
13
15
16
21.3
21.4
23.6
25.8
26.3
30
33.8
34.5
38
42.5
43
44
50
50.7
51.3
51.7
54
58
64
68.8
70
71
72.1
75
75.3
76
76.7
80
85
90.1
91
95
95.2
97
97.3
100
110
111
114.9
115
120
120.5
125
125.7
127
127.7
128
132.3
137.9
147
150
160
169.2
170
188.3
200
202.4
207
212
300
340
380
400
630.6

N.F

0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.6

Gain

26
26
26
26
26
26
26
26
26
26
26
26
26
26
26
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
24
22
22
22
22
20
20
20
18
16

Low mag version

no
no
no
no
no
no
no
no
no
no
no
no
no
no
no
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
yes
no

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