Th e project is supported by the Hungarian Scientific Research Fund (OTKA): T043145

The project is supported by the Hungarian Scientific Research Fund (OTKA): T043145TWEPP 2007 conference, Prague, 3-7 September 2007

Results and Consequences of Magnet Test and Cosmic Challengeof the CMS Barrel Muon Alignment System

Bencze, Gy. L.3,4, Béni, N.1, Imrek, J.2, Molnár, J.2, Novák, D.2,Raics, P.1, Sass, V2, Szabó, Zs.1, Székely, G.2 , Szillási, Z.1

More than 500 measurement cycles have been completed, the results can be summarized as follows:- The system worked correctly and provided results that could be interpreted.- The dynamic running scheme has proved to be very efficient leading to fully parallel operation of the board PCs.- A full cycle lasted about 100 minutes. This is already acceptable for future CMS operation, however, speed-up is foreseen.- Control of the operating muon chambers through the chamber DCS system went smoothly even at the maximum load of the channel.- A separate test has been made during the MTCC to check the operation of commercial Ethernet switch units in magnetic field. This test was also successful.- The resolution of the system in the most important phi-direction is ~20 micrometer, well below the specification. This enabled us to detect even thermal deformations due to the daily temperature oscillation.- The irreversible deformation (shrinkage) of the full barrel yoke during the first magnet operation as well as the elastic deformation under field during the changes of the magnetic field have been observed. The result is in good agreement with the preliminary finite-element calculations.

1 Institute of Experimental Physics, Debrecen University, Debrecen, Hungary H-40012 Institute of Nuclear Research (ATOMKI), Debrecen, PO BOX 51. Hungary H-40013 Institute of Particle and Nuclear Physics, Budapest, Hungary H-15254 CERN, CH-1211 Geneva 23, Switzerland.

Fig.1 Optical network of the Barrel Muon Alignment System

Wheel -2

Wheel -1

Wheel 0

Wheel +1

Wheel +2

Sector10

Sector11

Board PC (BPC)

PIConNET (PoN)

DT MiniCrate (MC)

DT XDAQsystem

5 MC

4 PoN + 1 PBC

2 BPC

8 PoN + 2 BPC

8 PoN + 1 BPC

8 PoN + 2 BPC

Main Workstation

Ethernetswitch DB

9 MC

Fig. 2 Part of the setup during the MTCC

Fig.3 Logical scheme of the MTCC setup

Fig.4 Flow diagram of the measurement cycle Fig.5 Data flow scheme

Fig.6 Daily thermal effects Fig. 7 Non-elastic shrinking of the barrel yoke

Dev

ice

Dev

ice

Dev

ice

Customprotocol

TCP/IP

PVSS

DIMConfiguration and

calibration data

measured dataJDBC

DetectorControlSystem

FSM

Devices:● MAB through BPC

- Cameras- LEDs- Temperature/Rel. Humidity

● Chamber LED sources (Forks) through PoN or XDAQ

Dev

ice

Dev

ice

LocalDB

Measurementcontrol (Java)

-Rigid structures (MABs, z-bars)

-Videocamera boxes (on the MABs)

-LED-holders (called forks) on the chambes

-Diagonal and z-LED holders (on the MABs and z-bars)

-Board computers (one for each MAB)

Barrelmuonchamber

MAB

MAB -1/9, DT 0/10/1R/Fork3/FLED1

Is it a barrelchamber LEDmeasurement?

Take next connectionfrom the list

Y

N

Y

Y

Y

Y

NN

N

Y

ReserveMAB of thegiven z-LED

Measure theconnection

(separate thread)

Are there anynon-measured connections?

Y

N

Set every connection as non-measured

N

N

STOPSTART

Get opticalconnection list

from DB

Y

End of singlemeasurement

thread

Opt

ical

line

isa

diag

onal

mea

sure

men

t

Repeatmeasurement

cycle?

Connection is already

measured?

Is the cam. MAB used by other

measurement?

Is the chamberused by other

measurement?

Is it a z-LED measurement?

N

Is the MAB used by other

measurement?

N

Reservechamber of the

given LEDReserve

MAB of thegiven camera

Set connectionto “under

measurement”

UnblockMAB of the

given z-LED

UnblockMAB of the

given camera

Y

N

N

Optical line is a diagonal measurement

Is it a barrel chamber LEDmeasurement?

Is it a z-LEDmeasurement?

Unblockchamber of

the given LED

Y

N

Set connectionto “bad

measurement” (+ errcode)

Was themeasurementsuccessfull?

Set connectionto “good

measurement”

Y

N

~15 μm

~2.7 mm

MAB +3/11, ZLED3, MTCC phase 1

~ 2.9 mm

MAB +3/11, ZLED3, MTCC phase 2

Fig. 8 Elastic shrinking of the barrel yoke