nanoPHYS’12 – December 17-19, 2012

K. Nakano, S. Miyasaka, K. Nagai and S. Obata (Department of Physics, Tokyo Institute of Technology)

Drift Chambers

12 cm

2 cm

Construction of New St. 3– Chamber

Performance Requirements

SeaQuest Spectrometer

Summary & Plan

Construction of Drift Chambers forDrell-Yan Measurement at FNAL SeaQuest

For Details & Commissioning Status … Poster by F. Sanftl

St. 3+ & St. 3– Chambers Structure – St. 3+ DC & New St. 3– DC

New St. 3– chamber is being constructed at FNAL toward the physics run.

Measuring Wire Tensions

Stretching Wires

Drift Property

Detection Efficiency

Hit distribution

Procedures

What’s Measured

• Muon pairs from Drell-Yan process• Momentum ~ 30 GeV/c Solid Iron:

Focusing

Magnet, Hadron

absorber and

beam dump

Iron Wall:

Hadron

Absorber

Station 1:

Hodoscope

array

Wire chamber

Station 4:

Hodoscope

array

Prop. tube

Station 2:

Hodoscope

array

Wire chamberLiquid H2, D2

& solid

targets

Station 3:

Hodoscope

array

Wire chamber

KTeV magnet:

Momentum

meas.

Proton

beam

120 GeV

Drell-Yan Process in Proton-Proton Reaction

• Front view

• Position & direction of sense wires• 6 planes• 14o tilt in U & V

• Cell structure

Guard wire

Sense wire

Field wire

Cathode wire

Muons

• Position resolution : 400 micron in horizon direction• Muons are bent in horizontal plane

• Rate tolerance : upto 1 kHz in wire length of 1 mm• Backgrounds due to muons from J/psi decay

>> Drell-Yan signals

Operation

• Gas : Argon (86%) + Methane (10%) + CF4 (4%)• HV : –2.4 kV (cathode & field), –1.4 kV (guard)

• Beam experiment for commissioning … March & April of 2012• Spectrometer upgrade … Now• Beam experiment for physics … Spring of 2013

Experiment Schedule

St. 3+ chamber has been tested• With the commissioning beam• With cosmic rays and a test chamber at Tokyo Tech

2012 02 Constructed the frame parts @ Japan

03 Transported the frame parts to Fermilab

06 Assembled the frame

07-10 Stretched all wires

11-12 Build & attach the Mylar windows / Start gas flow

2013 1-2 Build & attach the electronics for readout & HV / Start HV training

3 Test

4 ? Start the physics run

• Measurement with the commissioning beam

• With & without hodoscope hitsbeing matched

• GEANT4 simulation• Several mass ranges … J/psi,

D-Y near J/psi, D-Y w/ high mass, etc.

• To be compared with measurement• Dimuons from Drell-Yan, J/psi, Upsilons

• Measure the eigen frequency ( ) of wire free oscillation• External pulse w/ initiates the oscillation• Oscillation is detected as induced voltage• Amplitude gets maximum @

• Derive tension ( ) from by• • Accuracy: 0.5%

• 5,154 wires … 768 of sense wires & 4386 of other wires• Optimized procedure• 2 minutes/wire• 4 hour/shift x 2 shifts/day x 2 months

• Tension of wires• Adjusted by a metal block hanged• 75 gf for sense wires & 130 gf for other wires• Accuracy: 10% required & 5% (@ 3s) achieved!!

• SeaQuest measures Drell-Yan process, , in proton-proton reaction with 120 GeV proton beam at FNAL

• SeaQueast Japanese group constructs & operates two drift chambers at Station 3 (St. 3+, St. 3– )• The detail of the chamber characteristics are shown above

• St. 3+ chamber has been tested with the commissioning beam and with cosmic rays and test chamber at Tokyo Tech

• New St.3– chamber is being constructed at FNAL toward the physics run

SeaQuest Japanese group constructs & operates two drift chambers at Station 3 (St. 3+ & St. 3– )

• Wire• Sense : Au-W(Re), f30 mm• Others : Au-CuBe, f80 mm

• Measurement with test chamber & Ar:CO2 ( 80% : 20% )• Definition: efficiency of detecting one track by one plane

• Track coincidence of two scintillators covering 10 cm (5 wires) × 18 cm

• Efficient event one (or more) of wires in layerhas hit

• Efficiency ~ 100% within uncertainty at HV > 2.65 kV

• Spectrometer is being upgraded now for higher beam rate (× 10) in physics run• Detectors … St. 1 & St. 3– chambers• Beam … monitor & intensity stabilizer• Data acquisition … fast throughput

• A beam experiment for physics will start in Spring of 2013

• Measurement with test chamber & Ar:CO2 ( 80% : 20% )• Relation between drift distance & drift time

• Drift velocity ~ 30 micron/ns• Consistent with Garfield simulation

• Position resolution = event-by-event drift-time deviation 500 micron

Performance of St. 3+ Chamber

5 m × 5 m × 25 m