E906 Spectrometer Upgrade Overview

E906 Spectrometer Upgrade Overview

Paul E. Reimer

Experimental Approach

Impact on Fermilab

Magnet Coil Fabrication

Spectrometer Upgrades

211 December 2006 Paul Reimer E906 Sepctrometer Upgrade Overview

xtarget xbeam

Detector acceptance chooses xtarget and xbeam.

Fixed target ) high xF = xbeam – xtarget

Valence Beam quarks at high-x. Sea Target quarks at low/intermediate-x.

Drell-Yan scattering: A laboratory for sea quarks

E906

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Physics Requirements

Fundamentally want to measure and compare cross sections from a variety of targets as functions of di-muon Mass, x1, x2

Identify muons—hadron absorber and muon id wall Wide acceptance for desired muon kinematics

Resolve kinematics:

– Measure momentum of muons, reconstruct M, pL, x1, x2

– Depends on muon track reconstruction (through magnets)– Momentum measurement (2nd magnet strength)

Minimize background—muons from hadron decays– Absorber hadrons in dump and absorber before leptonic decay– Separate muon vertex—target vs. dump


E906 Spectrometer: Non-bend plane view

Trigger electronics

Scintillator Hodoscopes


Detector Resolution

Triggered Drell-Yan events

240 MeV

Mass Res.

0.04 x2

Res.


Basic Approach to Measuring Drell-Yan Scattering

Follow lead of pervious experiments: Proton beam on frequently interchanged targets 2 magnet spectrometer

– 1st magnet focuses muons into spectrometer– 2nd magnet provides momentum measurement

Beam dump within 1st magnet– Graded hadron absorber within 1st magnet to

prevent interact hadrons before decay

Target

1st magnet

2nd magnet

Final identificationTracking/Triggering

Stations


Spectrometer upgrade

Smaller Boost at 120 GeV than 800 GeV– Lorentz contract detector from 60 m to 25 m

E866

E906

– Requires new focusing magnet• Largest (non-Fermilab) part of upgrade

New Station tracking chambers for higher background rates

New Hodoscopes (material aging) New trigger (rates and flexibility)


M1 Magnet

New coils Reuse whole pieces of SM12

magnet yoke (SM12 was the 14.4 m dipole used by E866)


M1 Magnet Coil Fabrication Budget

Cost dominated by cost of conductor and coil ($1.3M of $1.6M)


Magnet Gantt Chart


Spectrometer Upgrade—Increased Rates

Significantly higher instantaneous luminosity in E906

(10£beam intensity) Smaller boost ) larger chance for mesons to decay before

interaction in beam dump

Solutions: Replace Station 1 Drift Chambers with MWPC’s (WBS 2.2.1—

Colorado) More flexible trigger (still modeled after E866, but in FPGA rather

than LeCroy units) (WBS 2.3—Rutgers) Double ended readout and mean timers on Station 3 and 4

hodoscopes (for single rf “bucket” resolution—19 ns) (WBS 2.1.1 and 2.1.3—Abilene)


Spectrometer Upgrades—Aging Equipment

E866 Station 3 and 4 scintillator dates from E605 in 1982 E866 Station 2 scintillator from 1989 upgrade—surplus material shows

significant crazing Large trigger efficiency corrections for some individual hodoscope

elements observed in E866 E866 Station1 of insufficient size for E906

Solution: Replace Scintillator with newer material

– Stations 1 and 2 recovered from HERMES muon hodoscope (WBS 2.1.2, Illinois)

– Station 3 and 4 new material (WBS 2.1.3, Abilene)


Spectrometer Elements Upgrade Budget

Primarily DOE/Office of Nuclear Physics with significant funds from NSF Key NSF contribution on TriggerKey NSF contribution on Trigger


Spectrometer Upgrade Gantt


Spectrometer Upgrade (cont.)


Contingency

Overall contingency ¼20%– Very standard techniques

Considered based on each WBS item, but held in commonheld in common– Technical—Existing design () Completely new design– Construction—Standard Techniques () New techniques/materials

Relatively standard techniques for all items– Schedule—Subsystem only () Critical Path

Schedule had minimal impact on contingency since delays were built into schedule.

– Additional contingency from outside factors (e.g. fluctuation of base aluminum conductor price, hydrocarbon price in scintillator)


Location FermilabOriginal

Meson East now used as Superconducting Cryo-Module Test Facility (SCMTF)

Alternatives Meson West

– Vertical bend spectro.—bends + into earth.

– 2nd magnet (SM3) must be assembled (but is available)

NM4 (KTeV)– Beam lime below grade allows a

horizontal bending spectrometer—bends + and - into earth

– 2nd magnet (KTeV) in hall– Nicer facility for physicists

Meson West

NM4 (KTeV)

Either location is acceptable to the collaboration

Fermilab is considering the impact of the experiment at both locations

In these talks, a vertical bend is assumed for historic reasons (i.e. E866/NuSea was that way)


Impact of E906 on Fermilab

Proton Impact:– 5 s slow extraction of 2£1012 protons/s each minute (possible

scheme) delivers requested protons within 2 yrs– Approx. 10% impact on neutrino production

Major Cost Drivers:– Beam Line– Cryogenics for liquid 1H and 2H targets– Assembly of Analysis Magnets

Lesser (but still significant) Items:– Detector Gas System– Electrical and Water Utilities for Magnets– Shielding– Magnetic Field Mapping Equipment– Utilities for electronics– Area Preparation


Summary of Overview

Experimental approach has been proven by previous Drell-Yan experiments (E866, E789, E772).– E906 Expects higher rates, but appropriate modifications (e.g.

Station 1 MWPC, double ended readout, trigger upgrade) have been made

M1 Magnet is the major construction cost driver on the part of DOE/Nuclear Physics– Economical reuse of SM12 yoke– Design underway w/budgetary estimates

Spectrometer upgrade requires only very conventional techniques– No technological show stoppers—uses well proven technology

Requires commitment from DOE/NP, Fermilab (DOE/HEP), NSF Realistic schedule could start data collection in 2 ½ years


Drell-Yan Acceptance

Programmable trigger removes likely J/ events

Transverse momentum acceptance to above 2 GeV

Spectrometer could also be used for J/, 0 studies

Documents

E906 Spectrometer Upgrade Overview