BigBite Hadron Detector Status

Hall A Collaboration MeetingXiaohui Zhan

On behalf of the E05-102 collaboration

MIT

Jun 21, 2007

BigBite Hadron Package:

• First used in SRC experiment: consists of an auxiliary plane and a trigger plane.

• Now the frame is under modification(Glasgow): for both threshold pi and 3He(e,e’d) experiments.

Goal: excellent discrimination between deuteron, proton, and unresolved kaon and pion at low momentum region.

E

dE

1. Remove upper longitudinal beams

2. Remove bottom beams

3. Lower the slantedsupport beams

New Frame SRC Frame

5. Remove auxiliary plane, reuse the beams in step 2 to construct the base

6. Add 4 newlongitudinal beams

4. Add cross steal beams to mount the wire chamber

7. Add bracketsto mount the shielding

Modification Inventory:

1. 100x100 Al EXTRUSION MA1-5-02-02/1050 x42. T BOLTS M8 A35-60 x203. T BOLTS M8 A35-20 x124. MOUNTING BRACKET A30-40 x165. MOUNTING BRACKET A30-00 x46. DOUBLE EXTRUSION NUT x127. UNIVERSAL CONNECTOR WITH BASE 50 A20-90 x12

Note: additional 4 pieces are added as support when the frame is tilted backward, so that we can lift the wire chambers straight up. Two steel bins which are used to hold the back wire chamber will be made by Jlab machine shop.

E-E Trigger plane• Consist of 24 scintillator bars• Dimension: 500x86x3 mm3 (E) 500x86x30 mm3 (E)• PMT test was done: higher HV was applied compared to SRC experiment• 56 PMTs have bad connection from light guide, they were taken off and being fixed…

Electronics Schematic Design (Bryan Moffit):• PMT signal flow diagram.• Rack setup and cable map• VDC read out not ready, but will be the same as that being used for the electron package.

Thanks to Glasgow technician group working on the frame modification:

We will be ready for the full package test when the updated wire chamber arrives!