Abstract
P-type point contact (PPC) high-purity germanium detectors are an important technology in astroparticle and nuclear physics due to their superb energy resolution, low noise, and pulse shape discrimination capabilities. Analysis of data from the Majorana Demonstrator, a neutrinoless double-β decay experiment deploying PPC detectors enriched in Ge76, has led to several novel improvements in the analysis of PPC signals. In this work we discuss charge trapping in PPC detectors and its effect on energy resolution. Small dislocations or impurities in the crystal lattice result in trapping of charge carriers from an ionization event of interest, attenuating the signal, and degrading the measured energy. We present a modified digital pole-zero correction to the signal energy estimation that counters the effects of charge trapping and improves the energy resolution of the Majorana Demonstrator by approximately 30% to around 2.4 keV full width at half-maximum at 2039 keV, the Ge76 Q value. An alternative approach achieving similar resolution enhancement is also presented.
| Original language | English |
|---|---|
| Article number | 045503 |
| Journal | Physical Review C |
| Volume | 107 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2023 |
Funding
This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under Contracts/Awards No. DE-AC02-05CH11231, No. DE-AC05-00OR22725, No. DE-AC05-76RL0130, No. DE-FG02-97ER41020, No. DE-FG02-97ER41033, No. DE-FG02-97ER41041, No. DE-SC0012612, No. DE-SC0014445, No. DE-SC0018060, No. DE-SC0022339, and No. LANLEM77/LANLEM78. We acknowledge support from the Particle Astrophysics Program and Nuclear Physics Program of the National Science Foundation through Grants No. MRI-0923142, No. PHY-1003399, No. PHY-1102292, No. PHY-1206314, No. PHY-1614611, No. PHY-1812409, No. PHY-1812356, No. PHY-2111140, and No. PHY-2209530. We gratefully acknowledge the support of the Laboratory Directed Research & Development (LDRD) program at Lawrence Berkeley National Laboratory for this work. We gratefully acknowledge the support of the U.S. Department of Energy through the Los Alamos National Laboratory LDRD Program and through the Pacific Northwest National Laboratory LDRD Program for this work. We gratefully acknowledge the support of the South Dakota Board of Regents Competitive Research Grant. We acknowledge the support of the Natural Sciences and Engineering Research Council of Canada, funding reference number SAPIN-2017-00023, and from the Canada Foundation for Innovation John R. Evans Leaders Fund. This research used resources provided by the Oak Ridge Leadership Computing Facility at Oak Ridge National Laboratory and by the National Energy Research Scientific Computing Center, a U.S. Department of Energy Office of Science User Facility. We thank our hosts and colleagues at the Sanford Underground Research Facility for their support.
| Funders | Funder number |
|---|---|
| Canada Foundation for Innovation John R. Evans Leaders Fund | |
| National Science Foundation | PHY-1003399, PHY-1812409, PHY-1206314, PHY-1614611, PHY-1102292, PHY-2209530, PHY-1812356, MRI-0923142, PHY-2111140 |
| U.S. Department of Energy | |
| Office of Science | |
| Nuclear Physics | DE-AC05-00OR22725, DE-AC05-76RL0130, DE-AC02-05CH11231, DE-SC0012612, DE-FG02-97ER41020, DE-FG02-97ER41033, DE-SC0022339, LANLEM77/LANLEM78, DE-FG02-97ER41041, DE-SC0018060, DE-SC0014445 |
| Oak Ridge National Laboratory | |
| Laboratory Directed Research and Development | |
| South Dakota Board of Regents | |
| Los Alamos National Laboratory | |
| National Energy Research Scientific Computing Center | |
| Natural Sciences and Engineering Research Council of Canada | SAPIN-2017-00023 |