Spacepix3

Pixel sensor for radiation monitoring and dosimetry.

Motivation

The SpacePix3 monolithic active pixel sensor, fabricated in 180nm silicon on insulator (SOI) CMOS technology, is a novel ASIC for space radiation monitoring and developed by the Czech Technical University in Prague. SpacePix3 is a High Voltage Monolithic Active Pixel Sensor (HV-MAPS) with an application-specific integrated circuit (ASIC) capable of measuring flux and deposited energy in pixels, distinguishing between different types of radiation. The main purpose of the detector is to monitor radiation in space because it is important to know about space weather, which is influenced by solar activity and poses a risk to human health, space infrastructure and terrestrial power systems, and terrestrial energy systems. In addition, the detector can be used for dosimetry and radiation visualisation, making it a particle tracking detector or a radiation camera. It can therefore be used in many more applications, such as medical radiation monitoring, and can also be modified to achieve neutron detection sensitivity.

The functional block diagram of the SpacePix3 ASIC.

Functionality The detector is capable of detecting and differentiating between protons, electrons and heavy ions. Its active sensor area is 3.84 × 3.84 mm², the pixel matrix is arranged in a 64x64 square array with 60 μm pitch, which allows the spatial resolution. The signal range of the pixel front-end amplifier is 1-80 ke-, extended up to 30 Me- via a backside channel. Diodes integrated into the grip wafer in each pixel are biased at -150 V, creating a depleted layer approximately 35 μm deep. An incident particle generates a charge pulse, which is converted into a voltage pulse by the charge-sensitive amplifier. The maximum voltage stored by the peak detector hold circuit is digitised using an on-chip 10-bit asynchronous column SAR ADCs. Two readout interfaces are available, 400 MHz LVDS and 50 MHz SPI. Total current consumption is 31 mA from a 1.8 V supply in SPI mode. Project Goals The Spacepix3 ASIC will be used for radiation monitoring on future space missions, in medical radiation facilities and in the laboratory. In addition, a dosimeter concept will be developed and a new spatially resolved gamma camera will be tested. It is also planned to combine the technology with other existing inhouse detector concepts to develop new concepts.

Functionality

The detector is capable of detecting and differentiating between protons, electrons and heavy ions. Its active sensor area is 3.84 × 3.84 mm², the pixel matrix is arranged in a 64x64 square array with 60 μm pitch, which allows the spatial resolution. The signal range of the pixel front-end amplifier is 1-80 ke-, extended up to 30 Me- via a backside channel. Diodes integrated into the grip wafer in each pixel are biased at -150 V, creating a depleted layer approximately 35 μm deep. An incident particle generates a charge pulse, which is converted into a voltage pulse by the charge-sensitive amplifier. The maximum voltage stored by the peak detector hold circuit is digitised using an on-chip 10-bit asynchronous column SAR ADCs. Two readout interfaces are available, 400 MHz LVDS and 50 MHz SPI. Total current consumption is 31 mA from a 1.8 V supply in SPI mode.

Project Goals

The Spacepix3 ASIC will be used for radiation monitoring on future space missions, in medical radiation facilities and in the laboratory. In addition, a dosimeter concept will be developed and a new spatially resolved gamma camera will be tested. It is also planned to combine the technology with other existing inhouse detector concepts to develop new concepts.

Navigation

Spacepix3

Direct Links 2