HKS detector package

The HKS detector package is designed to identify K$^+$s from p, $\pi^+$, e$^+$ backgrounds and to measure their momentum with a resolution of 2 $\times 10^{-4}$. In order to realize the requirements, the HKS detector package consists of drift chambers, time-of-flight walls, aerogel Cerenkov counters, and water Cerenkov counters. Table 11 summarizes the HKS detector package and their parameters.

表 11: Detectors for the E01-011 experiment

Nomenclature	Size	Comments
Drift chamber
HDC1	$30^H \times 120^W \times 2^T cm$	xx'uu'(+30 deg)vv'(-30 deg)
		5 mm drift distance
HDC2	$30^H \times 120^W \times 2^T cm$	xx'uu'(+30 deg)vv'(-30 deg)
		5 mm drift distance
Time of flight wall
HTF1X	$30^H \times 125^W \times 2^T cm$	7.5$^W$ cm $\times$ 17-segments, H1949
HTF1Y	$30^H \times 125^W \times 2^T cm$	3.5$^W$ cm $\times$ 9-segments, H1949
HTF2X	$35^H \times 170^W \times 2^T cm$	9.5$^W$ cm $\times$ 18-segments, H1949
Cerenkov counter
HAC1	$35^H \times 180^W \times 30^T cm$	n = 1.055 hydrophobic aerogel
		16 $\times$ 5" PMT
HAC2	$40^H \times 135^W \times 30^T cm$	n = 1.055 hydrophobic aerogel
		16 $\times$ 5" PMT
HWC1	$35^H \times 180^W \times 3^T cm$	10$^W$ cm $\times$ 18-segments, H1161
HWC2	$35^H \times 180^W \times 3^T cm$	10$^W$ cm $\times$ 18-segments, H1161
		Water with wavelength shifter

Detail description of each detector is given in following subsections.