E852 Documentation: Detector Positions

This page is designed to be a repository of information on the positions of detectors for E852.

1995 Survey (postscript)

Target Center

X Position = .560" (1.4224 cm)
Y Position = 0.0" (0.0 cm)
Z Position = 70" (177.8 cm)
Source: Survey Log dated 12-22-94 (TA)

CsI

X Position = .560" (1.4224 cm)
Y Position = 0.0" (0.0 cm)
Z Position of downstream end = 84.139" (213.713 cm)
Source: Survey Log dated 12-22-94 (TA)

LGD

Z Position on front face = 280.475" (712.407 cm)
Source: Eric Scott (TA)

EV/BV

X and Y Position varies. Must be determined from motor readout.
Z Position = 274.93" (698.32 cm)
Source: Measurement by Todd Adams

Coordinates For Target,DEA and LGD
A note on positioning before 1994 run

Detector positions for 1997 run (proposal)

MPS magnet will be set at 3/4 field during 1997 run. As a result some elements will be shifted from their positions in 1995 run.

There are 2 possible scenarios:

  1. Beam is parallel to the target at its center; normals to TDX4 and LGD have ~3mrad angle with MPS center line (variant I);
  2. TDX4 and LGD are perpendicular to MPS center line; beam has ~3mrad angle at the target center (variant II).

The calculations below were done for 18.25 GeV/c beam and for 1' hydrogen target.

95 run97 run (Var.I)97 run (Var.II)
.was not usedwas used
MPS magnet rotation angle, mrad32.8(max)29.032.8(max)
Beam angle at the target center, mrad-4.50.03.7
X of beam at the target center, cm1.421.662.33
Beam angle at DEA center, mrad-24.1-14.9-11.1
X of beam at DEA center, cm-0.260.761.89
X of DEA center to shadow LGD, cm~ -3.5-1.170.04
Beam angle at LGD mid-depth, mrad-43.6-30.4-26.6
X of beam at LGD mid-depth, cm-18.0-11.5-8.6

Variant II seems to be the better choice.

Note: Variant II was chosen for 1997 running.

Positions of C9 and H9 for the 1997 run (actual).