DMAPS Research and Development programme
Built on the previous experience of planar silicon sensors development within the Particle Physics group at Liverpool, we are doing R&D on novel Depleted Monolithic Active Pixel Sensors (DMAPS). These sensors have been adopted for the pixel tracker for the Mu3e experiment and are under consideration for several LHC experiments.
DMAPS are position sensitive detectors in industry standard CMOS processes. These sensors are extremely attractive for experiments in particle physics, as they integrate the sensing element and the readout electronics in a single layer of silicon. This removes the need for interconnection with complex and expensive solder bump technology to a readout chip, which results in faster turnaround times and lower production costs when compared to traditional planar silicon sensors. Given its huge potential, DMAPS can become the sensor technology of choice for the next generation of experiments in particle physics.
To cope with the large doses of radiation expected at particle physics experiments, DMAPS can be in a variant of standard CMOS processes that is called High Voltage-CMOS (HV-CMOS). So far, we have investigated three different commercial HV-CMOS processes in three technology nodes. These are Austria Micro Systems (ams) in the 0.35 μm and 180 nm nodes, TSI Semiconductors in the 180 nm node and LFoundry in the 150 nm node. Together with our international collaborators, we have designed, submitted for fabrication and evaluated several prototype detectors. These include the first large area detectors (~ 2 cm x 2 cm) for the Mu3e and ATLAS experiments (MuPix8, H35DEMO and ATLASPix1), and more generic oriented R&D prototypes to pursue improved position accuracy, timing resolution and radiation tolerance (RD50-MPW1 and RD50-MPW2).
We are focused on different topics related to the R&D of DMAPS:
- Sensor simulation at the physics level with TCAD
- Sensor and readout electronics design with Cadence
- Control and acquisition systems
- Sensor characterization
Layout of a 50 µm x 50 µm DMAPS pixel, the smallest pixel to date with all the readout circuitry embedded in the sensing area of the pixel, included in the RD50-MPW1 prototype and co-designed by Liverpool.
One of our PhD students doing charge collection efficiency measurements of a DMAPS prototype to study the radiation tolerance of these sensors in the cleanrooms in Liverpool.
Photograph of the MuPix8 prototype for the Mu3e experiment mounted on its carrier board [photo credit Niklaus Berger]. This experiment will search for the decay of a muon to three electrons. Any measurement of this decay would be a clear sign of new physics. The Mu3e requires tracking detectors with very low mass (50 μm thin) and excellent timing resolution (< 0.1 ns), which at present can only be achieved with DMAPS.
Members of the group
Academic and Research Staff:
- Gianluigi Casse
- Joost Vossebeld
- Sven Wonsak
- Matthew Franks (PhD, joint appointment with Fondazione Bruno Kessler, Italy)
- James Gooding (PhD)
- Sam Powell (PhD)
- Chenfan Zhang (PhD, joint appointment with Fondazione Bruno Kessler, Italy)
- Matthew Buckland (PhD, co-supervised by CERN CLICdp group, thesis)
- Lingxin Meng (PhD, co-supervised by University of Geneva, ATLAS group, thesis)
- Daniel Franklin (MSc)
- Liam Kelly (MSc)
- Phillip Marshall (BSc)
- E. Vilella et al., Report on recent activities in HV-CMOS detectors for Mu3e, ATLAS and RD50, J. Instrum. 13 (2018) C07002.
- E. Vilella et al., First results on the ATLAS HL-LHC H35DEMO prototype, J. Instrum. 12 (2017) C05001.
- E. Vilella et al., Prototyping of an HV-CMOS demonstrator for the High Luminosity-LHC upgrade, J. Instrum. 11 (2016) C01012.
For more information, and opportunities to work with this group please contact Eva Vilella.