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First measurement Results from DANAE - Demonstrating DePFET RNDR on a prototype Matrix

by Alexander Bähr, Holger Kluck, Peter Lechner, Jelena Ninkovic, Jochen Schiek, Hexi Shi, Wolfgang Treberspurg, Johannes Treis

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Submission summary

Authors (as registered SciPost users): Alexander Bähr
Submission information
Preprint Link: scipost_202211_00018v2  (pdf)
Date accepted: 2023-03-27
Date submitted: 2023-01-09 08:55
Submitted by: Bähr, Alexander
Submitted to: SciPost Physics Proceedings
Proceedings issue: 14th International Conference on Identification of Dark Matter (IDM2022)
Ontological classification
Academic field: Physics
  • High-Energy Physics - Experiment
  • Nuclear Physics - Experiment
Approach: Experimental


In the search for dark matter particle candidates, the mass region below 1 GeV/c2 is relatively unprobed. Utilizing a low-noise silicon sensor as sensitive target material, we aim to study the event signature of recoils between dark matter candidates and bound electrons. As the deposited energy is only a few eV, a sensor capable of detecting these low signals is required. We present first measurements on a prototype pixel matrix. It is based on the RNDR DePFET principle and provides a deep sub-electron readout noise of 0.2 e- and below.

Author comments upon resubmission

  • “as sensitive target material “ -> “as a sensitive target material ”

  • “scattering of a Dark Matter particle on an electron is possible ” - please provide a ref. included reference to " R. Essig, M. Fernandez-Serra, J. Mardon, A. Soto and T. Volansky, Direct detection of sub-gev dark matter with semiconductor targets, JHEP 05 (2015), doi:10.1007/JHEP05(2016)046."

  • “The long-term objective of DANAE is” - can you explain what is DANAE (abbreviation, experiment, project)? abbreviation included.

  • “large volume silicon detector ” - dimensions will be useful here included in the text as (several grams of sensitive mass). Details will be fixed in the future

  • “-200°C” - provide in brackets the corresponding value in K done

  • “Next the collected signal is read out. For the readout …” - if it is possible avoid read out and readout close to each other. Now reads: "Next the collected signal is read out. For this, we implemented an n-fold trapezoidal weighting,"

  • Fig.2 provide more details for (b). caption now reades: "The slopes of the linear fits for different events from selected pixels is histogrammized. Most slopes are following a gaussian distribution with mean value close to zero. However, wings on both sides of the gaussian are present, indicating that the charge can increase or decrease during the readout."

  • “We selected events ” - “We have selected events ”

  • “In addition to the signal, charge can be generated by thermal excitation, leading to leakage current and, furthermore, charge can be generated during the switching of the DePFETs gate by impact ionization – similar to the effect known as spurious charge generation in CCDs [7].” - “charge can be generated” second time is not necessary. removed repetition

  • “This implant serves as transfer channel ” - > “This implant serves as a transfer channel ”

  • Fig. 3, I would use italic for colors. done

  • “neglect events” ?? changed to "filter events"

  • For the last section “summary” I would recommend to provide a comparison of achieved “low readout noise” to used by others. A few word on future plans would be interesting too. changed paragraph to : We presented first measurements on a small prototype DePFET RNDR matrix of 64×64 pixels. As anticipated, the matrix can provide low readout noise of 0.23e− at 100 repetitions and 0.14 e− at 800 repetitions, similar to skipper CCDs [9] but limited by charge generation as well as charge losses for this prototype. At this stage we can detect these events and remove them from the data. The limitations will be mitigated by an optimized technology and operation conditions for a next generation of RNDR DePFETs. Further qualification of the current device will also include more advanced readout schemes with sparse clear only every few frames, providing an incremental readout of the collected charge. In the long term we plan to assemble a RNDR based sensor array with a mass of several grams of sensitive volume.

Published as SciPost Phys. Proc. 12, 066 (2023)

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