1. News from Cracow on the forward tracking
J. Smyrski
Jagiellonian University, Cracow, Poland
Construction of a prototype straw module
Measurement of wire tension in straws
Simulations and optimization of the forward tracking
x-t relation in non-homogenous magnetic field
PANDA FWD Meeting, GSI-Darmstadt,

2. PANDA FWD Meeting, GSI-Darmstadt, 3.03.2009
Module: 2x 16 straws
printing board for RC elements
straws
printing boards for positioning
and grounding straws
gas in
out
PANDA FWD Meeting, GSI-Darmstadt,

3. Assembling modules in a detection plane
rotation center
support frame
double layer : vertical wires (0) and (0)
or inclined wires (+10) and (-10)
PANDA FWD Meeting, GSI-Darmstadt,

4. One tracking station with four double-layers
Two double layers
with vertical wires
Two double layers
with inclined wires
e.g. (+10) and (-10)
Two double layers
with vertical wires
PANDA FWD Meeting, GSI-Darmstadt,

5. Gluing the straws together
1 layer
2 layers
pressure 2 bars
droplets of glue
PANDA FWD Meeting, GSI-Darmstadt,

6. Transferring the module
frame
PANDA FWD Meeting, GSI-Darmstadt,

7. Mounting on the support frame
Module on the support frame
after removing the transfer frame
PANDA FWD Meeting, GSI-Darmstadt,

8. PANDA FWD Meeting, GSI-Darmstadt, 3.03.2009
plans
test the procedure of transferring and installing the modules on the support frame
measure the positions and deformations of straw (photo-modeler)
measurement of high voltage characteristics,
determination of the noise level
test of reliability of the electrical contacts to straws
PANDA FWD Meeting, GSI-Darmstadt,

9. Device for measuring wire tension
Principle of measurement:
generation of voltage pulse (30 V, 1 ms) through wire placed in magnetic field
measurement of frequency of dumped oscillations by observation of waveform
of induced current
PANDA FWD Meeting, GSI-Darmstadt,

10. Measurement of wire tension
Minimum field to measure signal frequency: ~0.5 T cm
PANDA FWD Meeting, GSI-Darmstadt,

11. Measurement of wire tension
20 μm Tungsten wire
L = 1.10 m
 =
PANDA FWD Meeting, GSI-Darmstadt,

12. Simulations of the forward tracking
Work of Ola Wronska
PandaRoot framework
Kalman filter
Detection efficiency (~98%)
and position resolution (~60μm)
based on the results of tests
of the Juelich straws
Momentum determination
using 3 pairs of the forward
tracking stations;
each station contains
4 double layers of straws
Bl = 2 Tm, p(μ) = 1.5 GeV/c
DC6
DC5
DC4
DC3
DC2
DC1
PANDA FWD Meeting, GSI-Darmstadt,

13. PANDA FWD Meeting, GSI-Darmstadt, 3.03.2009
Momentum resolution
PANDA FWD Meeting, GSI-Darmstadt,

14. PANDA FWD Meeting, GSI-Darmstadt, 3.03.2009
Main objectives
Main factor(s) limiting the momentum resolution,
Influence of the forward RICH on the tracking,
Required inclination of wires,
Required position resolution,
Required extension of active areas in the x direction.
PANDA FWD Meeting, GSI-Darmstadt,

15. PANDA FWD Meeting, GSI-Darmstadt, 3.03.2009
Variation of x-t relation in non-uniform magnetic filed of the dipole magnet (calculations with the GARFIELD)
track z x
straw
Gas mixture: 90% Ar + 10% CO2
Gas pressure: 2 bar
Sense wire voltage: V
variation of Bx
variation of By
PANDA FWD Meeting, GSI-Darmstadt,

16. PANDA FWD Meeting, GSI-Darmstadt, 3.03.2009
Stray field in the tracking stations before and after the dipole magnet
Components Bx, By, Bz of stray magnetic field within the active volumes of the tracking stations DC1, DC2, DC5, DC6 are smaller than 0.35 T
Variation of x-t relation along one straw and from straw to straw in one detection plane is smaller than 0.05 mm
DC 1 2 3 4 5
PANDA FWD Meeting, GSI-Darmstadt,

17. Non-uniform magnetic field inside the dipole magnet gap
Resulting corrections (of up to ~0.35 mm)
to x-t relation can be in principle calculated
using GARFIELD and applied as function
of x- and z-coordinate for each straw layer
PANDA FWD Meeting, GSI-Darmstadt,