극저온 광음극 고에너지 극초단 전자회절(UED) 펨토초 번치 펄스 압축 및 RF 편향 공동(Deflecting Cavity) 지터 보상 C# SIMD 서보

3. Zero-Allocation C# SIMD 펨토초 번치 압축 서보 구현

RF 편향 스트리킹 카메라의 전자 스팟 영상 프로파일을 초고속 분석하여 번처 RF 진폭과 펨토초 위상 천이기를 10,000 Hz로 능동 잠금하는 C# .NET 9.0 엔진입니다.

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

namespace ZeliDesk.Quantum.UltrafastDiffraction
{
    public readonly ref struct UedBeamTelemetry
    {
        public readonly float StreakedSpotFwhmMicrons; // Spot width on screen
        public readonly float BeamEnergyMev;           // e.g. 3.05 MeV
        public readonly float ElectronChargePerBunchPc;// Charge ~ 0.15 pC
        public readonly float RfPhaseErrorDegrees;     // Phase jitter
        public readonly float PhotocathodeLaserPowerMw;

        public UedBeamTelemetry(float spotUm, float eMev, float qPc, float phaseErr, float pLaser)
        {
            StreakedSpotFwhmMicrons = spotUm;
            BeamEnergyMev = eMev;
            ElectronChargePerBunchPc = qPc;
            RfPhaseErrorDegrees = phaseErr;
            PhotocathodeLaserPowerMw = pLaser;
        }
    }

    public ref struct UedServoCommands
    {
        public float BuncherCavityVoltageKv;
        public float RfPhaseShifterDegrees;
        public float ReconstructedPulseDurationFs;
        public float TemporalResolutionFs;
        public bool Sub10FemtosecondAchieved;
    }

    public static class UltrafastElectronBunchCompressionEngine
    {
        private const float DeflectorCalibrationMicronPerFs = 12.8f; // 12.8 um/fs streak speed
        private const float UnstreakedBeamSpotMicrons = 45.0f;        // Static beam size

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void OptimizeBunchCompression(
            in UedBeamTelemetry telemetry,
            ref UedServoCommands output)
        {
            // 1. Reconstruct Temporal Duration from Streaked Spot Size
            // sigma_y^2 = sigma_y0^2 + (S * sigma_t)^2
            float totalSpot = telemetry.StreakedSpotFwhmMicrons;
            float staticSpot = UnstreakedBeamSpotMicrons;

            float netStreakSpotSq = MathF.Max(0.0f, totalSpot * totalSpot - staticSpot * staticSpot);
            float pulseDurationFs = MathF.Sqrt(netStreakSpotSq) / DeflectorCalibrationMicronPerFs;
            output.ReconstructedPulseDurationFs = Math.Clamp(pulseDurationFs, 4.0f, 250.0f);

            // 2. Closed-Loop RF Buncher Amplitude Servo
            // Optimum compression requires precise V_buncher
            float targetDurationFs = 7.5f; // Target 7.5 fs
            float durationError = pulseDurationFs - targetDurationFs;

            float baseBuncherKv = 185.0f; // Nominal ~185 kV for 3 MeV beam
            float buncherTune = durationError * 1.45f;
            output.BuncherCavityVoltageKv = Math.Clamp(baseBuncherKv + buncherTune, 120.0f, 250.0f);

            // 3. Laser-RF Timing Jitter Phase Servo
            float phaseCorrection = -telemetry.RfPhaseErrorDegrees * 0.85f;
            output.RfPhaseShifterDegrees = Math.Clamp(phaseCorrection, -15.0f, 15.0f);

            // 4. Overall Instrument Temporal Resolution
            // tau_total = sqrt(tau_pulse^2 + tau_jitter^2)
            float phaseJitterFs = MathF.Abs(telemetry.RfPhaseErrorDegrees) * 9.72f; // at 2.856 GHz, 1 deg ~ 0.972 ps = 972 fs
            float residualJitterFs = phaseJitterFs * 0.05f; // After closed-loop lock
            float totalResolutionFs = MathF.Sqrt(pulseDurationFs * pulseDurationFs + residualJitterFs * residualJitterFs);
            output.TemporalResolutionFs = totalResolutionFs;

            output.Sub10FemtosecondAchieved = (totalResolutionFs <= 10.0f);
        }
    }
}