SQUID Electronics

For rf SQUID readout, a novel JSQ Electronics V 5.0 is available. This new version features a quartz-controlled synthesizer with a frequency stability of about one ppm and an adjustable phase shifter for demodulation. The frequency stability of the synthesizer is several orders of magnitude better than that of previously used voltage controlled oscillators. Thus, temperature-dependent drift of working point adjustment is not an issue any more. The adjustable demodulation phase allows to compensate for variable length of the coaxial cable to the SQUID. The JSQ Electronics is operated and remote-controlled by means of a micro controller, the JSQ Tiger Controller. The working points of the SQUID sensors are stored in non-volatile memory. An auto-reset function can be activated, then a SQUID reset is performed automatically if the output voltage approaches the +/- 10V limit.

The JSQ Electronics V 5.0 is available with 1, 2 or 3 preamplifier units, one for each SQUID sensor. A heating option is available which allows to apply a heating current to the SQUID for a preset time in order to remove trapped flux from the sensor’s superconducting thin film. The JSQ Electronics V 5.0 can be operated either by the built-in touchpanel or by remote control from a computer.


adjustmentvia USB or RS232 bus
frequency450 ... 900 MHz
rf power -72 ... -118 dBm
max. slew rate >200,000 Phi0 / s
max. bandwidth 200 kHz
dynamic range up to +/- 240 Phi0 (+/- 800 nT)
output analog +/- 10V
feedback resistor 1 ... 20 kOhm (8 steps)
feedback capacitance 330 pF ... 100 nF (7 steps)
power consumption +15 V / 700 mA, -15 V / 400 mA
size 22mm × 83mm × 158mm
weight 700 g