JAMES F. JAKOBSEN GRADUATE FORUM 2003

STUDY ON CMS HF LIGHT-GUIDE SYSTEMS IN UNIVERSITY OF IOWA

ByFIRDEVS DURU

DEPARTMENT OF PHYSICS AND ASTRONOMY

OUTLINE

• LHC projectCMS experimentHF Calorimeter

• Light Guide Tests on:Materials (Al Mylar and HEM )

Shapes ( straight , tapered )Radiation hardness

LHC PROJECT

• LHC (Large Hadron Collider) is an accelerator

• The LHC will be built on the France-Switzerland border west of Geneva

• Will start running at 2007

LHC

• 14 TeV (Center of Mass Energy) proton-proton collisions at every 28 ns. • High Luminosity (1034 cm2s-1).

Raw Data: 1000 Gbit/sRaw Data: 1000 Gbit/s

5 TeraIPS5 TeraIPSEvents:

10 Gbit/sEvents:

10 Gbit/s

10 TeraIPS10 TeraIPS

Controls: 1 Gbit/s

Controls: 1 Gbit/s

To regional centers 622 Mbit/s

To regional centers 622 Mbit/s

CMS networks, farms and data flows

Remote control rooms

Remote control rooms

Controls: 1 Gbit/sControls: 1 Gbit/s

CMS EXPERIMENT

• CMS (Compact Muon Solenoid) detector has been designed to detect cleanly the diverse signatures from new physics by identifying and precisely measuring muons, electrons and photons over a large energy range and at high luminosity.

• The main physics interests:Standard Model (SM) Higgs boson Minimum Supersymmetric Standard Model (MSSM) Higgs bosonsGluino, squark searches.

CMS DETECTOR

Length : 21.6m Diameter : 14.6m

Weight : 14500 tons Four main parts: Magnet, Muon

system, tracking, calorimeter

CMS detector

HF Calorimeter

• 11 m away from interaction point

• Identification of very forward jets from heavy Higgs production

• High radiation region (~1 Grad of radiation field near beam pipe)

• Quartz fibers (QQ, QP)

• Iron as absorber

• LIGHT GUIDES

• PMT’s

HF Calorimeter

Constructed parts of HF Cal

PURPOSE OF THE LIGHT GUIDE TESTS

• Test the effect of the light guides on the uniformity of the PMT Signal by measuring the X-Y uniformity and attenuation[Optical properties – mixing]

• Comparison of the tapered light guides vs. non-tapered ones.

• Comparison of the different types of reflective materials (HEM, Al Mylar)

• Test the effect of radiation on two materials

LIGHT GUIDE TEST SETUP

Setup (the box where the light is produced)

Setup (the box where the light guide stands)

X uniformity without light guide

Y uniformity without light guide

X and Y uniformities with Al Mylar light guide

X-Y uniformities with HEM (straight) light guide

Light guide ratio comparison(HEM Straight / Al Mylar)

Results obtained in the test beam

TWO DIFFERENT SHAPES

X-Y uniformities with HEM (tapered) light guide

Light guide ratio comparisonHEM – (Straight / Tapered)

RADIATION TESTS

• Source: Cs137 at 9k Currie

( University of Iowa Hospitals and Clinics, Radiation Laboratories )

• 5 different irradiation levels:

2Mrad, 4Mrad, 6Mrad, 8Mrad, 10Mrad

Irradiated/non-irradiated ratio (HEM)

• Bullet 2mrad

• Box 4mrad• Triangle 6mrad• Star 8mrad• Circle 10mrad

Irradiated / non-irradiated ratio (Al Mylar)

Output reduced by 15-17% after radiation

CONCLUSION

• Better results with HEM

PMT X-Y uniformity improves and goes to a plateau when HEM reflecting material is used

• No significant difference between tapered and straight light guides

• No radiation damage was observed for HEM

Output decrease in irradiated Al Mylar