发表机构
Department of Astronomy & Astrophysics, University of California, San Diego; Space Sciences Laboratory, University of California, Berkeley（天文学与天体物理学系，加州大学圣地亚哥分校; 空间科学实验室，加州大学伯克利分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出一种固定调制准直器架构，利用多栅格对四相解调及游标级联技术，实现无移动部件的伽马射线暴宽视场快速精确定位。
AI 中文摘要
快速、精确的伽马射线暴（GRB）定位需要硬X射线和软伽马射线能量下的连续宽视场成像。我们开发了一种固定（非旋转）调制准直器架构来应对这一挑战。一个双栅准直器，即放置在简单非成像光子计数探测器前方的一对对齐的周期性狭缝栅格，通过三角形条纹图案透射离轴源，其局部角位置（即源相位）通过几个具有固定相对相位偏移的栅格对中的同时计数率恢复，而非像经典旋转调制准直器那样通过机械旋转单个栅格对。这些计数率的四相解调稳健地消除了探测器本底和栅格泄漏，无需旋转。由于条纹图案在天空中重复，一个相位测量对应多个候选源位置；我们通过一系列逐渐变粗栅距的栅格级联来解决这一模糊性，从而在任意宽的视场上实现定位，推广了最初用于定位Sco X-1的双栅游标尺技术。这种游标级联技术降低了在宽视场上实现精细角分辨率所需的光子计数和栅格校准精度。通过正交级联推广到二维，所提出的架构实现了无移动部件、无时间调制且仅需简单光子计数探测器的宽视场定位，是支持时域和多信使天体物理学的简单、廉价、连续监测仪器的有前景候选方案。
英文摘要
Rapid, precise localization of gamma-ray bursts (GRBs) requires continuous wide-field imaging at hard X-ray and soft gamma-ray energies. We develop a fixed (non-rotating) modulation-collimator architecture to address this challenge. A bigrid collimator, a pair of aligned, periodic slit grids in front of a simple, non-imaging photon-counting detector, transmits an off-axis source through a triangular fringe pattern whose local angular position, the source phase, is recovered from simultaneous count rates in several grid pairs at fixed relative phase offsets, rather than by mechanically rotating a single grid pair as in the classical rotating modulation collimator. Four-phase demodulation of these count rates robustly cancels detector background and grid leakage without requiring rotation. Because the fringe pattern repeats across the sky, a phase measurement corresponds to many candidate source positions; we resolve this ambiguity over an arbitrarily wide field of view using a cascade of progressively coarser-pitched grid stages, generalizing the two-grid vernier-scale technique originally used to localize Sco X-1. This vernier cascade technique reduces the required photon counts and grid-calibration accuracy required to achieve fine angular resolution over a broad field of view. Generalized to two dimensions with orthogonal cascades, the resulting architecture achieves wide-field localization with no moving parts, no time modulation, and only simple photon-counting detectors, a promising candidate for simple, inexpensive, continuous-monitoring instruments supporting time-domain and multi-messenger astrophysics.
Comments19 pages, 4 figures, submitted to The Astronomical Journal
