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Picosecond Precision Heavy Ion Detector for Λ Hypernuclei Lifetime Studies

Simon Zhamkochyan, Sergey Abrahamyan, Amur Margaryan, Hayk Elbakyan, Aram Kakoyan, Samvel Mayilyan, Artashes Papyan, Hasmik Rostomyan, Anna Safaryan, Gagik Sughyan, Narek Margaryan, Garnik Ayvazyan, John Annand, Kenneth Livingston, Rachel Montgomery, Patrick Achenbach, Josef Pochodzalla, Dimiter Balabanski, Satoshi Nakamura, Ani Aprahamian, Vanik Kakoyan

TL;DR

This work presents a novel heavy ion detector for direct measurements of heavy $\Lambda$ hypernuclei lifetimes using a circular RF scanning Radio Frequency Timer that translates event timing into spatial hits on a position-sensitive detector. The design emphasizes efficient suppression of prompt background and clear separation of delayed decays from hypernuclear lifetimes (approximately $200$ ps) via delayed-fission signals. Laboratory tests with alpha sources and RF-synchronized lasers demonstrate a baseline time resolution near $12$ ps and the detector’s ability to resolve lifetime-like spectra, while graphene studies show lifetime tails analogous to hypernuclear decays. Monte-Carlo simulations predict a practical lifetime measurement precision around $10$ ps under realistic experimental conditions, supporting feasibility for upcoming experiments with RF-driven electron, photon, or proton beams.

Abstract

In this paper, we present the design and preliminary performance evaluation of a new heavy ion detector for direct measurements of heavy Λ hypernuclei lifetime. The detector employs the previously developed 10 picosecond resolution Radio Frequency (RF) Timer, which converts the temporal information of incident particles into spatial coordinates of secondary or photoelectrons on a position-sensitive detector by means of circular RF scanning in the 500-1000 MHz range. Here, we report the detector design to achieve efficient suppression of accidental background and effective separation of prompt reaction products and delayed events from Λ hypernuclei decays, results of test studies carried out with RF synchronized laser as well as preliminary results obtained by using alpha particles. Dedicated Monte-Carlo simulations have been performed to estimate the detector's performance under realistic experimental conditions at RF-driven electron, photon, or proton beams. The results confirm the feasibility of the proposed design and provide a basis for upcoming experimental measurements, based on the delayed fission detection.

Picosecond Precision Heavy Ion Detector for Λ Hypernuclei Lifetime Studies

TL;DR

This work presents a novel heavy ion detector for direct measurements of heavy hypernuclei lifetimes using a circular RF scanning Radio Frequency Timer that translates event timing into spatial hits on a position-sensitive detector. The design emphasizes efficient suppression of prompt background and clear separation of delayed decays from hypernuclear lifetimes (approximately ps) via delayed-fission signals. Laboratory tests with alpha sources and RF-synchronized lasers demonstrate a baseline time resolution near ps and the detector’s ability to resolve lifetime-like spectra, while graphene studies show lifetime tails analogous to hypernuclear decays. Monte-Carlo simulations predict a practical lifetime measurement precision around ps under realistic experimental conditions, supporting feasibility for upcoming experiments with RF-driven electron, photon, or proton beams.

Abstract

In this paper, we present the design and preliminary performance evaluation of a new heavy ion detector for direct measurements of heavy Λ hypernuclei lifetime. The detector employs the previously developed 10 picosecond resolution Radio Frequency (RF) Timer, which converts the temporal information of incident particles into spatial coordinates of secondary or photoelectrons on a position-sensitive detector by means of circular RF scanning in the 500-1000 MHz range. Here, we report the detector design to achieve efficient suppression of accidental background and effective separation of prompt reaction products and delayed events from Λ hypernuclei decays, results of test studies carried out with RF synchronized laser as well as preliminary results obtained by using alpha particles. Dedicated Monte-Carlo simulations have been performed to estimate the detector's performance under realistic experimental conditions at RF-driven electron, photon, or proton beams. The results confirm the feasibility of the proposed design and provide a basis for upcoming experimental measurements, based on the delayed fission detection.
Paper Structure (6 sections, 5 equations, 9 figures)

This paper contains 6 sections, 5 equations, 9 figures.

Table of Contents

  1. Introduction
  2. Heavy Ion Detector Concept and Design
  3. Laboratory Tests
  4. Fission Yields and Secondary-Electron Production in the Context of $\Lambda$-hypernuclear Lifetime Experiment Feasibility
  5. Expected lifetime measurement performance: Monte-Carlo simulations
  6. Summary

Figures (9)

  • Figure 1: The schematic of the Heavy Ion Detector. 1 - target, 2 - accelerating electrode, 3 - magnet, 4 - collimator, 5 - electrostatic lens, 6 - deflector, 7 - RF synthesizer, 8,9 - deflected electrons, 10 - PSD, 11 - accelerator's RF system.
  • Figure 2: Schematic of the position sensitive detection system.
  • Figure 3: Scanned secondary electrons generated by alpha particles from the plutonium source.
  • Figure 4: Laboratory test setup for RF-synchronized photon measurements.
  • Figure 5: Left: Circularly scanned photoelectron image on the PSD. Two runs are overlaid: the RF-Off case shows a central spot used for calibration; the RF-On case produces the circularly scanned image, which can be translated into time information. Right: Corresponding phase distributions in nanoseconds. Top: gold layer; bottom: monolayer graphene.
  • ...and 4 more figures