Impact of charge trapping on the energy resolution of Ge detectors for rare-event physics searches

Mei, Dongming; Mukund, R; Wei, Wenzhao; Panth, Rajendra; Liu, J.; Mei, Hao; Li, Y.-Y.; Acharya, Pramod; Bhattarai, Sanjay; Kooi, Kyler; M., Raut,; Sun, Xiang-Yu; Kirkvold, Alex; Dong, K.-M.; Meng, Xianghua; Wang, G.-J.; Yang, Gang

doi:10.1088/1361-6471/ab9796

Cited by 18 publications

(17 citation statements)

References 80 publications

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“…The relationship between the trapping cross-section of charge carriers and the trapping length λ trap is described by the following equation 28,29 :…”

Section: Physical Modelmentioning

confidence: 99%

Dipole and Cluster Dipole States of HPGe Detectors at Cryogenic Temperature

Raut

Mei

Bhattarai

et al. 2023

Preprint

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This study investigates new technology for enhancing the sensitivity of low-mass dark matter detection by analyzing charge transport in a p-type germanium detector at 5.2 K. To achieve low-threshold detectors, precise calculations of the binding energies of dipole and cluster dipole states, as well as the cross-sections of trapping affected by the electric field, are essential. The detector was operated in two modes: depleted at 77 K before cooling to 5.2 K and cooled directly to 5.2 K with various bias voltages. Our results indicate that the second mode produces lower binding energies and suggests different charge states under varying operating modes. Notably, our measurements of the dipole and cluster dipole state binding energies at zero fields were 8.716+/-0.435 meV and 6.138+/-0.308$ meV, respectively. These findings have strong implications for the development of low-threshold detectors for detecting low-mass dark matter in the future.

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“…The relationship between the trapping cross-section of charge carriers and the trapping length λ trap is described by the following equation 28,29 :…”

Section: Physical Modelmentioning

confidence: 99%

Dipole and Cluster Dipole States of HPGe Detectors at Cryogenic Temperature

Raut

Mei

Bhattarai

et al. 2023

Preprint

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“…Research and development on zone refining of Ge ingots, growing them into high purity crystals and their characterization are being done at the University of South Dakota [26][27][28][29][30]. Also, we fabricate and characterize the Ge detectors made from the USD grown crystals for rare event searches [31][32][33][34]. After purifying Ge ingots to a level of ∼10 11 /cm 3 by zone refining [29], a single crystal can be grown through the Czochralski method [35].…”

Section: Production Of Charge Carriers Via Phonon Excitation and Ioni...mentioning

confidence: 99%

Low-Energy Solar Neutrino Detection Utilizing Advanced Germanium Detectors

Bhattarai¹,

Mei²,

Raut³

2021

Preprint

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We explore the possibility to use advanced germanium (Ge) detectors as a low-energy solar neutrino observatory by means of neutrino-nucleus elastic scattering. A Ge detector utilizing internal charge amplification for the charge carriers created by the ionization of impurities is a novel technology with experimental sensitivity for detecting low-energy solar neutrinos. Ge internal charge amplification (GeICA) will amplify the charge carriers induced by neutrino interacting with Ge atoms through emission of phonons. It is those phonons that will create charge carriers through the ionization of impurities to achieve an extremely low energy threshold of ∼0.01 eV. We demonstrate the phonon absorption, excitation, and ionization probability of impurities in a Ge detector with impurity levels of 3×10 10 cm −3 , 9×10 10 cm −3 , and 2×10 11 cm −3 . We present the sensitivity of such a Ge experiment for detecting solar neutrinos in the low-energy region. We show that, if GeICA technology becomes available, then a new opportunity arises to observe pp and 7Be solar neutrinos. Such a novel detector with only 1 kg of highpurity Ge will give ∼ 10 events per year for pp neutrinos and ∼ 5 events per year for 7Be neutrinos with a detection energy threshold of 0.01 eV.

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“…This model was applied to a-Ge contacts on HPGe detectors as well [38]. Leakage current is directly proportional to temperature as reported in these studies [18][19][20][21][34][35][36][37][38][39].…”

Section: I-v-t Characteristics and Cbh Measurementmentioning

confidence: 99%

“…Several papers have been published on the investigation of the CBH of rectifying contacts by studying the current-voltage (I-V) or capacitance-voltage (C-V) characteristics [18][19][20][21][22][23][24][25][26]. In this study, we have used the I-V characteristics at different temperatures.…”

Section: Introductionmentioning

confidence: 99%

Implication of the Temperature-Dependent Charge Barrier Height of Amorphous Germanium Contact Detector in Searching for Rare Event Physics

Panth¹,

Wei²,

Mei³

et al. 2021

Preprint

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The exploration of germanium (Ge) detectors with amorphous Ge (a-Ge) contacts has drawn attention to the searches for rare-event physics such as dark matter and neutrinoless double-beta decay. The charge barrier height (CBH) of the a-Ge contacts deposited on the detector surface is crucial to suppress the leakage current of the detector in order to achieve la ow-energy detection threshold and high-energy resolution. The temperature-dependent CBH of a-Ge contacts for three Ge detectors is analyzed to study the bulk leakage current (BLC) characteristics. The detectors were fabricated at the University of South Dakota using homegrown crystals. The CBH is determined from the BLC when the detectors are operated in the reverse bias mode with a guard-ring structure, which separates the BLC from the surface leakage current (SLC). The results show that CBH is temperature dependent. The direct relation of the CBH variation to temperature is related to the barrier inhomogeneities created on the interface of a-Ge and crystalline Ge. The inhomogeneities that occur at the interface were analyzed using the Gaussian distribution model for three detectors. The CBH of a-Ge contact is projected to zero temperature. The implication of the CBH at zero temperature is discussed for Ge detectors with a-Ge contacts in searching for rare-event physics.

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Impact of charge trapping on the energy resolution of Ge detectors for rare-event physics searches

Cited by 18 publications

References 80 publications

Dipole and Cluster Dipole States of HPGe Detectors at Cryogenic Temperature

Dipole and Cluster Dipole States of HPGe Detectors at Cryogenic Temperature

Low-Energy Solar Neutrino Detection Utilizing Advanced Germanium Detectors

Implication of the Temperature-Dependent Charge Barrier Height of Amorphous Germanium Contact Detector in Searching for Rare Event Physics

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