BigBite Spectrometer Equipment

by

Douglas W. Higinbotham

BigBite Family of Experiments

• Threshold Pion Production (Hadron Package) {Cryo-Target}

• Transversity & d2 (Electron Package) {3He Target}

• Ay (HRS) & (e,e’d) (Hadron Package) {3He Target}

BigBite Infrastructure For Transversity

• Magnet Continues To Work Without Issue (one spare coil)

• Power Supply Has Had Only Minor Problems– Problem Tends To Be With Communication– We Rarely Change Field, So Not Big Issue– Technicians Have Tried To Fix This

• Extremely Tight Space To Get To 30 Degrees– New Right Foot Designed and Ordered– Work On Beam-line Area Needs To Be Done (Folts)

• GEN Field Clamp Extended• Re-use GEN Side Shielding • Add Better Internal Shielding (Multi-Experiment Problem)

BigBite Detectors For Transversity

• Three Full Wire Chambers– Send Middle Chamber To UVa During March– Designer Assigned– Upgrade Chamber Major Item For Review

• Trigger Scintillators• PreShower & Shower Detector

– Several PMTs Marginal (near 2kV) and Few Dead

– Either Buying 60 PMTs or 10 PMTs• NEW Gas Cherenkov Designed by Brad

– Major Item For Review– Asked JLab For 60k This FY For This Project

Wire-Chamber Electronics

• We have both VME and Fastbus! Though would need four more VME units for middle chamber read-out.

• 200 pre-Amp cards and associate equipment in production.

– Over 100 have been delivered.

– Rest In The Electronics Group’s Queue

• 40 more pre-Amp cards are being ordered.

• 210 needed for three 6 plane chambers (240 total order)

Electronics and Cables

• All experiments will share wirechamber electronics.• The pi0 & (e,e’d) experiments will be using mostly

their own NIM/CAMAC electronics.• d2 and Transversity NIM/CAMAC electronics

converging, BUT not yet finalized. – Brad is adding Cherenkov to trigger setup– Must be done in the coming week!– Albert Coming To Help Supervise Construction

Test Lab

• All BigBite experiments share the test lab space.– Douglas Manages The Space– Eugene Is Area Safety Warden

• Bertha Power Supply (440V) Needs To Be Moved To Test Lab– Single Source Of Power– Solves Outlet Problem and Hopefully Grounding Problems

• Safety Is Important– Some Items Need Safety Procedures– Procedures Needs Many Signatures

• Once GEP III Leaves, We Will Get Some Space Back• BUT, It Will Continue To Be Very Crowded

– Work Safely!