Elliptical Analysis for DM Cross-Section Calculation in Japan

Evaluation of the elliptical analysis in Japan to calculate DM cross-section Atsuhiro UMEMOTO

Scanning and Analysis Procedure of NIT 70nm 1stselection signal candidate selected by brightness cut 2ndselection Rescan candidates to get the track length and angle by elliptical fitting 3rdselection Background rejection by phase contrast imaging, plasmon super-resolution .. In this analysis, energy resolution (threshold) and angler resolution are determined by elliptical analysis.

Task of elliptical fitting Elliptical analysis has to - The relation between track length and ellipticity - The angler determination accuracy Underground experiment in 2016 Angler distribution with elli>=2 Current elliptical fitting makes an anisotropic angler distribution

Requirement to calculate the DM sensitivity Length of nuclear recoil ellipticity If we know the relation about all target nuclei, the threshold of track length (= recoil energy ) in NIT detector can be determined. To get the relation, I will compare a simulation with experiment data. simulation - SRIM + AgBr crystal structure of NIT + optical image by waveform tool the simulated image is analyzed by elliptical fitting Data - Carbon ion by ion implantation and CNO recoil by neutron Simulation Data Elliptical analysis works well and the understanding of NIT detector is promoted.

Requirement to calculate the DM sensitivity Length of nuclear recoil ellipticity If we know the relation about all target nuclei, the threshold of track length (= recoil energy ) in NIT detector can be determined. To get the relation, I will compare a simulation with experiment data. simulation Asada works Shiraishi works - SRIM + AgBr crystal structure of NIT + optical image by waveform tool the simulated image is analyzed by elliptical fitting Data - Carbon ion by ion implantation and CNO recoil by neutron Simulation Data Elliptical analysis works well and the understanding of NIT detector is promoted.

As a first step A simple track is simulated by WaveFormTool Fresnel diffraction Waveform function Wave propagation with lens effect N.A 1.4 510 nm Focal length 5 mm magnification x100

40 nm spherical particle (the distance is 260 nm) 51 pixel Accuracy of Image making 1.7 nm Number of pixel in calculation 16384 pixel Outpitch 55 nm/ pixel Elliptical analysis is applied to the simulated image. And the angle is rotated with 15 degree.

Elliptical analysis 1 Conventional elliptical fitting algorithm is used. - Blur filter (5 5) Low Path Filter (15 kernel size) Subtracted elliptical fitting - OpenCV library minor and angle major and angle 7 12 6.5 11 6 10 5.5 minor(pix) majr(pix) 9 5 8 minor major 4.5 7 4 6 3.5 3 5 0 15 30 45 60 75 90 105 120 135 150 165 180 0 15 30 45 60 75 90 105 120 135 150 165 180 angle angle

Result1 ellipticity and angle 3 2.5 2 ellipticity 1.5 ellipticity 1 0.5 0 0 15 30 45 60 75 90 105 120 135 150 165 180 angle Set angle 180 75 60 45 30 15 180 165 150 135 120 105 90 Angle 179.103 71.564 59.180 45.000 30.820 18.436 179.103 161.564 149.180 135.000 121.162 108.436 90.000 Angle 0.897 3.436 0.820 0.000 -0.820 -3.436 0.897 3.436 0.820 0.000 -1.162 -3.436 0.000 Minor 5.475 5.324 5.258 4.710 5.258 5.324 5.475 5.324 5.258 4.697 5.107 5.324 5.469 minor_rate 1.000 0.972 0.960 0.860 0.960 0.972 1.000 0.972 0.960 0.858 0.933 0.972 0.999 Major 9.877 10.206 10.584 10.895 10.584 10.206 9.877 10.206 10.584 10.977 10.731 10.206 10.025 major_rate 0.900 0.930 0.964 0.993 0.964 0.930 0.900 0.930 0.964 1.000 0.978 0.930 0.913 Ellipticity 1.804 1.917 2.013 2.313 2.013 1.917 1.804 1.917 2.013 2.337 2.101 1.917 1.833 elli_rate 0.772 0.820 0.861 0.990 0.861 0.820 0.772 0.820 0.861 1.000 0.899 0.820 0.784

Elliptical algorithm Elliptical analysis2 Bicubic Gaussian blur (9 9) LPF (15 kernel size) Subtracted elliptical fitting Elliptical analysis3 Bicubic Gaussian blur (9 9) LPF (15 kernel size) Subtracted moment fitting

Result2 major minor angle_minor angle_major 8 25 7 20 6 5 15 4 10 3 2 5 1 0 0 0 15 30 45 60 75 90 105 120 135 150 165 180 0 15 30 45 60 75 90 105 120 135 150 165 180 angle(degree) angle(degree) elli RATE angle_elli 105 3.5 3 100 2.5 95 Rate(%) 2 major 90 1.5 minor 85 1 0.5 80 0 30 60 90 120 150 180 0 angle(degree) 0 20 40 60 80 100 120 140 160 180 200 angle(degree) dr = 260 nm , elli = 2.808 ~3.097, 9.3 % Elliptical fitting is a shape analysis. The shape after image processing is not same in each angle.

Result3 angle minor angle major 7 6.8 19 6.6 18.5 6.4 18 6.2 17.5 minor 6 17 major 5.8 16.5 5.6 16 5.4 15.5 5.2 15 5 14.5 -90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90 14 -90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90 angle angle rate angle elli 1.1 3 1.05 2.5 <3.5 1 2 0.95 ellipticity rate 0.9 1.5 minor 0.85 1 major 0.8 0.5 0.75 0.7 0 -90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90 -90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90 angle angle

Several distance and angle dr=20, 40,..,260 nm d =15,30, .180 degree.

Result3 angle(degree) angle_ellipticity Angler resolution and distance 3.5 200 150 3 100 2.5 50 2 ellipticity 0 0 50 100 150 200 250 300 1.5 -50 distance (nm) 1 -100 -150 0.5 -200 0 -105 -90 -75 -60 -45 -30 -15 0 15 30 45 60 75 90 105 angle It has a good angler determination accuracy (< 3 degree @ distance is more than 80 nm) Ellipticity has a angler dependence if the brightness of event is low (dr = 260 nm , max brightness = 250, ellipticity = 2.88~ 2.79( 3 %) max brightness = 60, ellipticity = 2.75~ 2.95( 7 %)

Summary and prospect The understanding of elliptical analysis is important to decide the energy threshold and angler resolution in Dark Matter search I study the quality of elliptical analysis by using Waveform simulation. Prospect By using elliptical analysis3, I evaluate the track length and ellipticity. Experimental data, Carbon track, CNO recoil by neutron and dust are study soon.