방사광 X선 극저온 나노프로브 고체 다이아몬드 NV 센터 단일 스핀 양자 자력계 광학 검출 자기 공명(ODMR) 서보 C# SIMD 엔진

3. Zero-Allocation C# .NET 9.0 AVX-512 SIMD NV 양자 자력계 서보

100,000Hz 주기로 APD 광자 계수 신호를 복조하여 마이크로파 주파수 신시사이저를 제어하고 국소 자기장을 계측하는 초정밀 실시간 서보 엔진입니다.

using System;
using System.Runtime.CompilerServices;
using System.Runtime.Intrinsics;
using System.Runtime.Intrinsics.X86;

namespace ZeliDesk.Stem.DiamondNv
{
    public readonly record struct NvApdTelemetry(
        float PhotonCountRateMegaCps,
        float CurrentMicrowaveFreqGhz,
        float PhotodiodeLaserRefMw,
        float CryoStageTempKelvin
    );

    public readonly record struct QuantumMagnetometerOutput(
        float MeasuredMagneticFieldMicroTesla,
        float ResonanceSplittingMhz,
        float CorrectedZfsGhz,
        bool ResonanceLocked
    );

    public ref struct DiamondNvMagnetometerServo
    {
        private const float GYROMAGNETIC_RATIO_MHZ_PER_MT = 28.024f; // 28.024 MHz / mT
        private const float NOMINAL_ZFS_GHZ = 2.870f;

        private readonly float _kp;
        private readonly float _ki;
        private float _integralErrPlus;
        private float _integralErrMinus;
        private float _freqPlusGhz;
        private float _freqMinusGhz;

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public DiamondNvMagnetometerServo(float kp, float ki)
        {
            _kp = kp;
            _ki = ki;
            _integralErrPlus = 0.0f;
            _integralErrMinus = 0.0f;
            _freqPlusGhz = NOMINAL_ZFS_GHZ + 0.015f; // 초기 추정
            _freqMinusGhz = NOMINAL_ZFS_GHZ - 0.015f;
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public QuantumMagnetometerOutput StepServo(ref readonly NvApdTelemetry telem, float dt, bool trackingPlusBranch)
        {
            // 1. 공명 형광 딥 기울기 에러 역산
            // 형광 기준치 대비 딥 깊이 (통상 10~20% 콘트라스트)
            float normPl = telem.PhotonCountRateMegaCps / MathF.Max(1.0f, telem.PhotodiodeLaserRefMw * 15.0f);
            float errorSlope = normPl - 0.85f; // 딥 저점 목표 0.85

            if (trackingPlusBranch)
            {
                _integralErrPlus = Math.Clamp(_integralErrPlus + errorSlope * dt, -0.05f, 0.05f);
                _freqPlusGhz += (_kp * errorSlope + _ki * _integralErrPlus) * dt;
            }
            else
            {
                _integralErrMinus = Math.Clamp(_integralErrMinus + errorSlope * dt, -0.05f, 0.05f);
                _freqMinusGhz -= (_kp * errorSlope + _ki * _integralErrMinus) * dt;
            }

            // 2. 공명 주파수 분폭 Delta f = f+ - f- 및 순수 자기장 도출
            float deltaFMhz = MathF.Abs(_freqPlusGhz - _freqMinusGhz) * 1e3f;
            float bMicroTesla = (deltaFMhz / (2.0f * GYROMAGNETIC_RATIO_MHZ_PER_MT)) * 1e3f; // uT
            float zfsGhz = (_freqPlusGhz + _freqMinusGhz) * 0.5f;

            bool locked = MathF.Abs(errorSlope) < 0.02f;

            return new QuantumMagnetometerOutput(bMicroTesla, deltaFMhz, zfsGhz, locked);
        }

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void BatchComputeZeemanSplittingSimd(ReadOnlySpan fieldsTesla, Span outSplittingsMhz)
        {
            float coeff = 2.0f * GYROMAGNETIC_RATIO_MHZ_PER_MT * 1e3f; // MHz / T
            var vCoeff = Vector256.Create(coeff);

            int i = 0;
            for (; i <= fieldsTesla.Length - 8; i += 8)
            {
                var vB = Vector256.LoadUnsafe(in fieldsTesla[i]);
                var vSplit = Vector256.Multiply(vB, vCoeff);
                vSplit.StoreUnsafe(ref outSplittingsMhz[i]);
            }
            for (; i < fieldsTesla.Length; i++)
            {
                outSplittingsMhz[i] = fieldsTesla[i] * coeff;
            }
        }
    }
}