Evaluating the Effective Segregation Coefficient in High-Purity Germanium (HPGe) Crystals for Ge Detector Development in Rare-Event Searches

Fuente: arXiv
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Main Authors: Chhetri, S., Mei, D. -M., Bhattarai, S., Budhathoki, N., Warren, A., Dong, K. -M., Panamaldeniya, S. A., Prem, A.
Format: Preprint
Published: 2025
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author Chhetri, S.
Mei, D. -M.
Bhattarai, S.
Budhathoki, N.
Warren, A.
Dong, K. -M.
Panamaldeniya, S. A.
Prem, A.
author_facet Chhetri, S.
Mei, D. -M.
Bhattarai, S.
Budhathoki, N.
Warren, A.
Dong, K. -M.
Panamaldeniya, S. A.
Prem, A.
contents The performance and scalability of rare-event physics experiments depend on large-volume, detector-grade high-purity germanium (HPGe) crystals with precise control of impurity segregation during growth. We report a detailed study of impurity distribution in a single Czochralski-grown HPGe crystal produced at University of South Dakota (USD). The crystal was sectioned longitudinally into 37 segments, enabling the first high-resolution and systematic mapping of dopant profiles along the length of a detector-grade HPGe boule. Hall-effect measurements were used to extract impurity concentrations for boron (B), aluminum (Al), gallium (Ga), and phosphorus (P) in each segment. From these data, we determine effective segregation coefficients ($K_{eff}$) and initial melt concentrations ($C_0$) for the dominant dopants and compare them with classical Burton-Prim-Slichter expectations. The results provide quantitative insight into impurity transport and melt-solid partitioning under realistic detector growth conditions. These findings inform process-optimization strategies for HPGe crystal pulling, improve impurity control along the boule, and support the reliable fabrication of large, low-background HPGe detectors for next-generation rare-event searches.
format Preprint
id arxiv_https___arxiv_org_abs_2511_20879
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Evaluating the Effective Segregation Coefficient in High-Purity Germanium (HPGe) Crystals for Ge Detector Development in Rare-Event Searches
Chhetri, S.
Mei, D. -M.
Bhattarai, S.
Budhathoki, N.
Warren, A.
Dong, K. -M.
Panamaldeniya, S. A.
Prem, A.
Instrumentation and Detectors
Applied Physics
The performance and scalability of rare-event physics experiments depend on large-volume, detector-grade high-purity germanium (HPGe) crystals with precise control of impurity segregation during growth. We report a detailed study of impurity distribution in a single Czochralski-grown HPGe crystal produced at University of South Dakota (USD). The crystal was sectioned longitudinally into 37 segments, enabling the first high-resolution and systematic mapping of dopant profiles along the length of a detector-grade HPGe boule. Hall-effect measurements were used to extract impurity concentrations for boron (B), aluminum (Al), gallium (Ga), and phosphorus (P) in each segment. From these data, we determine effective segregation coefficients ($K_{eff}$) and initial melt concentrations ($C_0$) for the dominant dopants and compare them with classical Burton-Prim-Slichter expectations. The results provide quantitative insight into impurity transport and melt-solid partitioning under realistic detector growth conditions. These findings inform process-optimization strategies for HPGe crystal pulling, improve impurity control along the boule, and support the reliable fabrication of large, low-background HPGe detectors for next-generation rare-event searches.
title Evaluating the Effective Segregation Coefficient in High-Purity Germanium (HPGe) Crystals for Ge Detector Development in Rare-Event Searches
topic Instrumentation and Detectors
Applied Physics
url https://arxiv.org/abs/2511.20879