Basel Universität
Departement Physik
Departement Physik



For details about us, click on a name.

  Michael Steinacher
Head of electronics lab
  Roberto Maffiolini
Electronics technician
  Andreas Tonin
Electronics engineer
  Werner Erni
Associate engineer in electronics
  Sascha Linder
Electronics technician
  Fabio Cimei


Below we provide information about some of our products.

  Product Optical Intensity Stabilization – OIS (SP 999)

For the intensity stabilization of lasers and other light-sources the Optical Intensity Stabilization can be used. The OIS is a tiny box containing an optical detector (PIN-photodiode and amplifier) a PID-controller, a stable reference value and a 50 Ohm driver unit. The versatile OIS-box can be mounted directly onto an optical table with an M4 thread. The large area (7 mm2) photodiode is mounted in the center of a 30 mm cage plate (SM1, CP02/M from Thorlabs) and has a bandwidth of 500 kHz. It is suitable for wavelengths in a range from 400 nm to 1'100 nm. User Manual

  Product LNHS I to V Converter Remote Control Interface (SP 983a)

It is recommended to install the Low Noise / High Stability I to V Converter (SP 983) as close as possible to the sample. Therefore the I/V converter is often located in a places hard to access during running experiments. This Remote Control Interface allows for the remote control of the gain and LP cut-off frequency via a flat-cable with a length of serval meters. Since the remote control inputs on the LNHS I to V Converter are galvanically isolated by optocouplers no ground loops can occur. The Remote Control Interface comes with a 2.8'' touchscreen for manual control and has a serial port (RS-232) for simple ASCII communication with a computer. User Manual

This Remote Control Interface is based on a single-board Raspberry Pi B+ computer running a Linux operation system.

  Product Low Noise / High Stability I to V Converter (SP 983)

The LNHS I to V Converter combines low input voltage noise with high stability and low drift input voltage (< ±0.2 μV/K). This combination is very important for measurements on samples at temperatures near the absolute zero. Commercial available I/V converters suffer from higher input voltage noise or lower input voltage stability over temperature. The gain can be selected in decades from 105 up to 109 V/A and the low-pass filter can be adjusted between 30 Hz and 100 kHz. These settings can also be done remotely by using the Remote Control Interface (SP 983a). At the maximum gain (109 V/A) the bandwidth is typical 1.6 kHz and at the minimum gain (105 V/A) reaches 600 kHz. By applying an external voltage the input offset voltage can be varied within ±100 mV.

The device can be equipped with two different J-FETs in the input stage:

PRO: Lower input current noise (significant in the 108 and 109 V/A ranges)
CON: Slightly higher input voltage noise. Smaller gain-bandwidth-product (68 MHz) increases output noise at large input-capacitances.

2) HIGH-GBWP: IF3602
PRO: Slightly lower input voltage noise. Lager gain-bandwidth-product (620 MHz) makes output noise significant smaller at large input-capacitances.
CON: Higher input current noise (significant in the 108 and 109 V/A ranges)
Data Sheet HIGH-GBWP

  Product Magnetic Field Stabilization (SP 962)

The Magnetic Field Stabilization allows fast and precise controlling/stabilization of the magnetic field at certain location of the experiment. By using a magnetometer (e.g. from Bartington) the actual magnetic field is measured and a Helmholtz-coil driven by an external low-noise current source is used to control the field. The device is installed between the magnetometer and the coil driver current source. For controlling/stabilization of all three space axes three such devices are needed. The PID controller can be adjusted by potentiometers on the front-panel. For fast and precise switching the magnetic field the device automatically changes between PID- and PD-controller, depending on the output voltage of the coil driver current source. This reduces the switching-time of the magnetic field without over/under-shooting by more than a factor two. Detailed Description (German)

  Product Analog Selector Switch (SP 944)

The Analog Selector Switch allows fast and low-glitch switching between two analog voltages in a range of up to ±10 V. To prevent from interferences and ground-loops the TTL-compatible control input is galvanically isolated by an optocoupler. The low noise performance combined with the low ON-resistance (<200 Ohm) and a charge-injection smaller than 1 pC makes this switch suitable for high-sensitive physics experiments. The device can be mounted directly to the BNC connectors on the front-panel of the LNHR DAC (SP 927) and allows fast switching (up to 100 kHz) between two different low noise output voltages. Data Sheet

  Product Low Noise / High Resolution DAC (SP 927)

The LNHR DAC is an eight channel voltage source with exceptional low noise performance and high resolution. It is designed to drive high-ohmic gates with ultra-stable voltages in fundamental physics experiments at cryogenic temperatures. For such experiments constant DC bias-voltages and high resolution sweep-voltages with very low fluctuations are mandatory. The output range of ±10 V, combined with the 24 bit resolution, allows adjusting the voltages with a step size of only 1.2 μV. The output voltage noise is below 1 μVRMS, measured in a frequency range of 0.1 Hz to 100 Hz. With its bandwidth of DC…70 Hz the LNHR DAC can be used for DC-biasing, for ramping/sweeping and for low frequency waveform generation. The device can be controlled locally by the rotary/push knob (encoder) or remotely by using the RS-232 interface. The actual voltages can be displayed on the LCD. User Manual

For fast switching between two output channels of the LNHR DAC use the Analog Selector Switch (SP 944). To generate precise voltages up to ±100 V use the HV-Amplifier (SP 908).

  Product HV-Amplifier (SP 908)

If the standard ±10 V voltages, generated from the LNHR DAC (SP 927), are too low the HV-Amplifier with a voltage gain of ten can be used. It has an output voltage of up to ±100 V with a maximum output current of ±70 mA. To prevent from ground loops, the analog in/out are floating and not referenced to the ground/earth carried by the 230 V mains. An analog voltage-indicator on the front-panel shows the actual output voltage. The device can be used to drive capacitive-loads such as piezo-electrical crystals. The bandwidth can be switched between 10 kHz and 100 kHz; this makes it compatible with the Analog Selector Switch (SP 944). Data Sheet

  Product Piezo-Motor Controller – PMC (SP 869)

The Piezo-Motor Controller offers the flexible and robust operation of up to eight slip-stick piezo-motors. It allows a bidirectional movement in up to eight axes (channels), whereas only one axis can be driven at the same time. The PMC can drive a wide range of piezo-motor capacitances up to 15 nF. The saw-tooth output voltage of the PMC has a fast back-jump (slip) rise/fall time of only 1 μs at a load-capacitance of 10 nF. This leads to efficient and reliable operation of slip-stick piezo-motors also at cryogenic temperatures. The applied saw-tooth voltage can be adjusted from zero up to ±400 V and the frequency from 1 Hz up to 4 kHz. The PMC can be operated by the Hand-Control Unit (SP 869a) or via a computer-control interface. User Manual