#### Muon Tracker 

**Overview:** The purpose of the PHENIX Muon Arms is to enable the study
of vector mesons decaying into dimuon pairs, to allow the study of the
Drell-Yan process, and to provide muon detection in heavy flavor decays
all as part of both the relativistic heavy ion and spin physics programs
of PHENIX. Each muon arm must both track and identify muons, as well as
provide good rejection of pions and kaons; therefore, both a Muon
Tracker (MuTr) and a Muon Identifier (MuID) are needed. Each arm of the
Muon Tracker is comprised of three stations of tracking chambers,
mounted inside an end-cap muon magnet. Stations 1 and 2 have three
chamber gaps, with two cathode planes read out in each gap, and Station
3 has two chamber gaps. A survey system for monitoring chamber positions
in real time is an integral part of the tracking system. Two different
construction techniques are being used for the tracking chambers: the
first and last stations are constructed using honeycomb panels with
cathode strips on the inside surfaces and the central stations are
constructed as stacks of wires and etched foils attached to aluminum
frames. The Muon Tracker Front End Electronics comprises Front End
Modules (FEMs), each organized as a collection of 6U-size Eurocards
communicating over a common backplane. The approximately 100 chassis
containing about 200 FEMs needed to read out the cathode strips for each
Muon Arm are mounted inside the Muon magnet via a framework that is
independent of the detector mounts. The framework also provides
distribution manifolds and channels for all services run to both the
detectors and their front-end electronics, while keeping all
non-detector elements outside the Muon Arm acceptance.

Muon Tracking System Manager (Detector Council): M. Brooks (LANL)

Muon Tracking Mechanics Subsystem Manager: D. Lee (LANL)

Muon Tracking Electronics Subsystem Manager: D. Mischke (LANL)

Muon Tracking Chief Mechanical Engineer: W. Sondheim (LANL)

Muon Tracking Chief Electrical Engineer (analog): M. Cafferty (LANL)

Muon Tracking Chief Electrical Engineer (digital): S. Robinson (LANL)

Muon Tracking Electronics Chief Mechanical Engineer J. Archuleta (LANL)

Muon Tracking Integration Contact: W. Sondheim (LANL)

Brookhaven Production Factory Manager: R. Towell (LANL)

Muon Tracking Simulation Computing: M. Brooks (LANL)

58 Participants: Faculty/Staff (21), PostDocs (5), Engineers (20),
Students (6), Support (6)

10 Institutions: BARC, Korea U., Kyoto U., LANL, Louisiana State U., New
Mexico State

U., ORNL, RIKEN, U. New Mexico, Yonsei University

**Mechanical Progress:** The LANL, BNL, UNM, and NMSU factories are
completely ready for construction activities. After some severe
procurement delays due to problems at vendors we have begun construction
of the frames for station 2 and the panels for station 3. Station 1
procurements are arriving and drill jigs and the drill jig base panel
have been received. Although the production schedule has slipped badly
we still predict that the last octants will be delivered within a couple
of weeks of previous schedules. Pictures of the state of the factories
at the end of August follow. Figure 1 shows a picture of one of the
first cathode planes to arrive at the UNM factory. Figures 2-4 show
pictures of the LANL factory which is responsible for gluing the anode
and cathode

![](media/image1.png)

Figure 1. A picture of the first Station 1 cathode plane that has
arrived at the UNM factory.

![](media/image2.jpeg){width="5.497222222222222in"
height="4.129861111111111in"}

Figure 2. A photograph of the vacuum bag tables, with an anode wire
plane (foreground) and cathode plane (background) in the process of
being glued together.

![](media/image3.jpeg){width="5.502083333333333in"
height="4.1194444444444445in"}

Figure 3. A picture of an anode frame, on the glue table at the LANL
factory.

![](media/image4.jpeg){width="5.502083333333333in"
height="4.126388888888889in"}

Figure 4. A picture of a cathode frame, pinned to an outer chamber frame
at LANL.

![](media/image5.png)

Figure 5. The vacuum bag glue tables at the BNL factory which are used
to glue the station 3 panels together.

![](media/image6.jpeg){width="5.496527777777778in"
height="4.122222222222222in"}

Figure 6. The station 3 winder in the clean tent at BNL.

frames of station 2 together and stretching, gluing and etching the
cathode planes for station 2. Figure 2 is a picture of the vacuum bag
tables (in use) which are used to hold the pieces of the cathode and
anode frames together while they are being glued and Figures 3 and 4
show the first anode and cathode planes that have been produced at the
LANL factory. Figure 5 shows the vacuum bag tables at the BNL factory
which are used to glue the Station 3 panels together and Figure 6 shows
the BNL factory clean tent, where the station 2 and 3 anode wire planes
are wound, and the complete station 2 and 3 chambers are assembled and
tested.

Magnet infrastructure and scaffolding designs are complete and will be
in production after reviews are completed. A new calibration technique
involving pulsing a few anode wires was tested and shown to preserve the
resolution of 90 microns on a station 2 prototype chamber. This new
technique was incorporated into the design of the anode boards. After
studying the tracking performance without anode wires it was decided to
increase the number of stereo views in the cathodes for station 1 and 2.
The present scheme has stereo views of 11.25º, 7.5º, and 3.75º (with
respect to the non-stereo cathodes) for each octant at station 2 and
11.25º, -11.25º, and 6º for each octant in station 1. A new nonflammable
gas mixture consisting of Ar:CO~2~:CF~4~ was studied with the station 2
prototype chamber and the prototype cathode amplifiers and found to
operate quite well. We have adopted this new gas mixture as the baseline
gas.

The chamber gas system has progressed to a conceptual design that is now
under review. This system is now being directed by personnel from
RIKEN/Kyoto and will go into production when the review process is
complete. The gas system is a recirculating gas system designed to
preserve the expensive CF~4~ gas. The alignment system is also now under
the direction of RIKEN/Kyoto. The hardware designs for this system are
being completed and the components have been specified.

**Electronics Progress:** The design of the in-magnet mechanics for the
Muon Tracker Front-End Electronics (FEE) has been completed, reviewed
and released for fabrication by the AMC at NMSU. Prototype boards for
the FEE modules have been completed and are being tested. These include
the controller card (digital portion of the FEE), cathode readout card
(contains the preamplifier and AMU/ADC), and backplane. Figure 7 shows
the prototype CROC board, connected to a prototype backlplane, in a
prototype chassis. Figure 8 shows the same CROC board connected to a
test chamber which was built for FEE testing. The test chamber uses the
same anode and cathode PC boards that are being used for the Station 3
chambers, and is electrically the same as the final chambers will be.
Tests of the CROC with this test chamber are currently underway. The
boards to interface with the PHENIX fast signals (fiber-optic) are in
layout. The production cathode preamp chips have been ordered and an
automated test stand for these chips is under development. Planning is
underway for procurement, testing, and installation of the full FEE
system for the South Arm. This includes power, services, and ancillary
systems. The system for calibrating the gain and linearity of the
cathode channels will be designed soon.

![](media/image7.jpeg){width="7.0in" height="5.252777777777778in"}

Figure 7. A picture of the prototype CROC board, connected to a
prototype backplane.

**Computing Progress:** The muon tracker software was modified so that
it could find tracks with high efficiency in Central Au-Au collisions,
with no anode readout and the current configuration of cathode stereo
and non-stereo planes. The majority of the code has been ported to C++
and all code modifications that were necessary to write out Phenix Raw
Data Format (PRDF) events were made (PRDF is identical to real data
events). Code needed to write out Data Summary Tapes (DSTs), which will
be used for real data analyses as well as Monte Carlo analyses, was also
added. We participated in both PHENIX Mock Data Challenges and examined
the performance of picking out J/ tracks mixed in with central Au-Au
events by analyzing the DSTs that were written out. Work is underway to
write and read calibration and geometry information to/from the official
PHENIX Database, and to upgrade the software to be more object-oriented
now that the PHENIX software framework provides more support for this.

![](media/image8.jpeg){width="5.0in" height="6.666666666666667in"}

Figure 8. A picture of the prototype CROC board connected to the test
chamber, with the expected 24" cable.