• High Gain of 10¹³ V/C
• Wide Operating Range from 250 Hz to 15 MHz
• Low Input Noise of 40 x 10^-21 C/√Hz and 700 pV/√Hz
• Ideal for AC Coupled Charge Sources like Pyro- and Piezoelectric Detectors, Tuning Fork Quartz Crystals and Length Extension Resonators
• Typical Applications are Atomic Force Microscopy (AFM) and Charged Particle Beam Monitoring

A charge amplifier is a current integrator producing an output voltage proportional to the charge collected at the amplifier input over a certain amount of time. Often a charge amplifier needs a reset mechanism to avoid an overload of the integration stage. The HQA-15M-10T was designed for AC modulated signal sources with no average DC background current. The charge in these applications is alternating positive and negative and therefore no separate reset is required for the HQA-15M-10T because the average current is zero. Any long term or temperature related drift is canceled by the AC coupled input stage inside the amplifier.

A charge amplifier produces an output voltage proportional to the charge collected at the amplifier input. In contrast, the output signal of a current amplifier (also called transimpedance amplifier) is directly proportional to the current at the amplifier input. Current is the derivative of charge over time. Therefore, the output signal of a current amplifier is the derivative of the output waveform of an equivalent charge amplifier.

The HQA-15M-10T was designed for AC modulated charge sources like tuning fork quartz crystals and length extension resonators. The input stage of the amplifier uses a very low noise and high gain design to achieve an excellent sensitivity establishing charge measurements down to the Pico and Femto Coulomb range. In contrast to some other amplifiers, the HQA-15M-10T does not use or require any cooling to achieve its performance leading to a much simpler and more compact design. The small-sized housing allows the use close to the signal source avoiding signal perturbations due to long cables. Finally, its wide working range from 250 Hz to 15 MHz is ideal for versatile use with a broad selection of signal sources.

• Atomic Force Microscopy (AFM)
• Charged Particle Beam Monitoring