Vignesh Sitaraman
d63a422a41
new folder: cross_section, this folder allows for cross section calculations for the ANASEN data, a readme and some example files are provided modified: run_tr.sh
81 lines
4.2 KiB
Python
Executable File
81 lines
4.2 KiB
Python
Executable File
"""The ANASEN detectors as they are now (Run A, 27Al campaign), for the geometric efficiency.
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geometric_efficiency.py reads everything about the detectors from here. Change a number here and every efficiency
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computed afterwards follows it.
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Sources:
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- Si and counter: anasen_detectability.py of ~/TALYS/al027_a_scripts_stoichgas_dedx0962_2026-10-08
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("detector geometry as used by TrackRecon.C"; counter radii from ClassPW.h)
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- beam tube and PCB hole: the author, 2026-10-15 (../scratch/reaction_efficiency_tube_2026-10-15)
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Geometry only: straight tracks from the vertex, no energy loss.
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"""
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import numpy as np
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# ---------------------------------------------------------------- silicon
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# QQQ3: the downstream annular detector
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QQQ_Z_MM = 105.0 # TrackRecon.C qqq_z
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QQQ_R_MM = (50.0, 100.0) # inner and outer active radius (16 rings: rho = 50 + 50/16 (ring + 0.5))
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QQQ_PHI_FRACTION = 4 * 87.0 / 360.0 # 4 quadrants x 87 deg of wedges
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# SX3: the barrel; only the four detectors TrackRecon.C builds events for, downstream half only
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SX3_R_MM = 88.0
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SX3_Z_MM = (-3.0, 72.0) # z_local + 75/2 - 3
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SX3_IDS = (1, 3, 7, 9)
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SX3_HALF_ANGLE = np.arctan(4 * 40.30 / (8.0 * 88.0 * np.cos(np.radians(15.0)))) # outer strip edge, each side
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SX3_PHI_FRACTION = len(SX3_IDS) * 2 * SX3_HALF_ANGLE / (2 * np.pi)
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PHI_FRACTION = {"qqq": QQQ_PHI_FRACTION, "sx3": SX3_PHI_FRACTION}
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# Si energy thresholds (MeV), TrackRecon.C reaction_ax_core si_ecut. Used only for the eps_si_thr column.
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SI_THRESHOLD_MEV = {"qqq": 0.45, "sx3": 0.6}
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# ---------------------------------------------------------------- proportional counter
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COUNTER_HALF_LENGTH_MM = 174.3
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COUNTER_RADII_MM = (32.0, 37.0, 42.0) # guard, anode, cathode (ClassPW.h)
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# ---------------------------------------------------------------- upstream apertures
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# (name, radius mm, z mm of the face that binds). A track from an on-axis vertex only moves away from the axis,
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# so an opening binds at its downstream end.
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APERTURES = (("beam tube", 16.0, -189.0),
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("PCB hole", 18.0, -174.3))
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# ---------------------------------------------------------------- hit rules
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# z_vertex in mm, theta = lab polar angle of the particle (radians). All return one True/False per track.
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def hits_silicon(det, z_vertex, theta):
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"""Does the straight track from z_vertex at angle theta reach the active silicon of `det` ("qqq" or "sx3")?
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Polar angle only: multiply by PHI_FRACTION[det] for the azimuthal coverage.
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A track that reaches the SX3 barrel's z range is counted as SX3, not QQQ."""
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s, c = np.sin(theta), np.cos(theta)
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with np.errstate(divide="ignore", invalid="ignore"):
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z_at_sx3 = z_vertex + SX3_R_MM * c / s # z where the track reaches the barrel radius
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on_sx3 = (z_at_sx3 >= SX3_Z_MM[0]) & (z_at_sx3 <= SX3_Z_MM[1])
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if det == "sx3":
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return on_sx3
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r_at_qqq = np.where(c > 0, (QQQ_Z_MM - z_vertex) * s / c, -1.0) # radius where it reaches the QQQ plane
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if det == "qqq":
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return (QQQ_Z_MM > z_vertex) & (r_at_qqq >= QQQ_R_MM[0]) & (r_at_qqq <= QQQ_R_MM[1]) & ~on_sx3
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raise ValueError(f"unknown detector {det!r}: detectors.py defines 'qqq' and 'sx3'")
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def crosses_counter(z_vertex, theta):
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"""Does the track cross the guard, anode and cathode radii inside the counter's length?"""
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with np.errstate(divide="ignore", invalid="ignore"):
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cot = np.cos(theta) / np.sin(theta)
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ok = np.ones(np.shape(z_vertex), bool)
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for r in COUNTER_RADII_MM:
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ok &= np.abs(z_vertex + r * cot) <= COUNTER_HALF_LENGTH_MM
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return ok
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def clears_apertures(z_vertex, theta):
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"""Does the track pass the beam tube and the PCB hole? Only vertices upstream of an aperture can be blocked
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by it: blocked when the track is farther from the axis than the opening's radius at the opening's z."""
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s, c = np.sin(theta), np.cos(theta)
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tan_theta = s / np.where(c > 0, c, 1e-9) # backward tracks from upstream never reach the detectors
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ok = np.ones(np.shape(z_vertex), bool)
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for _name, radius, z_face in APERTURES:
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ok &= ~((z_vertex < z_face) & ((z_face - z_vertex) * tan_theta > radius))
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return ok
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