AIDT 온디바이스 STEM 방사광 X선 극저온 스트론튬(Sr-87) 광격자 시계 흑체복사(BBR) 4K 복사차폐 서보 제어기

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Stem.OpticalLatticeClock
{
    /// <summary>
    /// 4K 극저온 차폐체 온도 및 복사 텔레메트리 상태
    /// </summary>
    public readonly ref struct CryoShieldTelemetryState
    {
        public readonly double ShieldMeanTemperatureKelvin; // 차폐체 평균 온도 [K]
        public readonly double ThermalGradientMilliKelvin;  // 차폐체 표면 온도 구배 [mK]
        public readonly double ViewportLeakagePowerMicroW;  // 상온 뷰포트 누설 열복사 [uW]
        public readonly double AmbientRoomTempCelsius;      // 실험실 상온 배경 온도 [degC]

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public CryoShieldTelemetryState(double meanT, double grad, double leak, double roomT)
        {
            ShieldMeanTemperatureKelvin = meanT;
            ThermalGradientMilliKelvin = grad;
            ViewportLeakagePowerMicroW = leak;
            AmbientRoomTempCelsius = roomT;
        }
    }

    /// <summary>
    /// BBR 차폐 서보 명령
    /// </summary>
    public readonly ref struct BbrShieldServoCommand
    {
        public readonly double ShieldHeaterPowerMilliWatts; // 극저온 히터 가열 전력 [mW]
        public readonly double EstimatedBbrShiftHz;        // 실시간 BBR 주파수 천이량 [Hz]
        public readonly double RelativeFrequencyUncertainty;// 상대 주파수 불확도 (e.g. 1e-18)
        public readonly bool IsBbrUncertaintySuppressed;    // 10^-18 이하 달성 여부

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public BbrShieldServoCommand(double pwr, double shift, double uncert, bool suppressed)
        {
            ShieldHeaterPowerMilliWatts = pwr;
            EstimatedBbrShiftHz = shift;
            RelativeFrequencyUncertainty = uncert;
            IsBbrUncertaintySuppressed = suppressed;
        }
    }

    /// <summary>
    /// 10,000Hz 주기 광격자 원자시계 BBR 천이 동적 보정 서보 엔진
    /// </summary>
    public ref struct OpticalClockBbrCompensationServoEngine
    {
        private const double ClockFreqHz = 429228004229873.0; // Sr-87 시계 전이 주파수 (~429 THz)
        private const double BbrBeta = 2.13023;                // 300K 기준 BBR 계수 [Hz]
        private const double TargetShieldTempKelvin = 4.200;   // 목표 차폐 온도 4.2K

        private double _accumulatedHeaterPower;
        private double _prevTempError;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public BbrShieldServoCommand UpdateServo(
            in CryoShieldTelemetryState state, double dtSeconds)
        {
            // 1. T^4 기반 BBR 절대 천이 계산: delta_nu = -beta * (T/300)^4
            double tempRatio = state.ShieldMeanTemperatureKelvin / 300.0;
            double bbrShiftHz = -BbrBeta * Math.Pow(tempRatio, 4.0);

            // 2. 온도 오차 계산 및 PI 히터 제어
            double tempError = TargetShieldTempKelvin - state.ShieldMeanTemperatureKelvin;
            double tempRate = (dtSeconds > 1e-9) ? (tempError - _prevTempError) / dtSeconds : 0.0;
            _prevTempError = tempError;

            _accumulatedHeaterPower += 2.5 * tempError * dtSeconds;
            _accumulatedHeaterPower = Math.Clamp(_accumulatedHeaterPower, 0.0, 50.0);

            double commandHeaterPower = _accumulatedHeaterPower + 12.0 * tempError + 0.15 * tempRate;
            commandHeaterPower = Math.Clamp(commandHeaterPower, 0.0, 100.0);

            // 3. 상대 주파수 불확도 평가
            // delta_y = (4 * beta / nu_0) * (T/300)^3 * (delta_T / 300)
            double deltaT = (state.ThermalGradientMilliKelvin * 1e-3) + Math.Abs(tempError);
            double relUncertainty = (4.0 * BbrBeta / ClockFreqHz) * Math.Pow(tempRatio, 3.0) * (deltaT / 300.0);

            bool suppressed = relUncertainty < 5.0e-19;

            return new BbrShieldServoCommand(
                commandHeaterPower,
                bbrShiftHz,
                relUncertainty,
                suppressed
            );
        }
    }
}