1. SksMinus status 03
HB meeting
2008/5/02
白鳥昂太郎

2. Contents Around target SDC2 position SDC1 position SP0 position
Hyperball-J frame position
4He target
Beam line elements

3. SDC2 position Interference of preamp card. ⇒SDC2 to 50 mm upstream
Original SDC2 position
(it means the design position in the Geant4 simulation)
Interference of preamp card.
⇒SDC2 to 50 mm upstream
But, we can avoid to it by changing preamp arrangement.
New SDC2 position

4. Distance between SDC1 and SDC2
Original SDC2 position
Interference of preamp card.
⇒SDC2 to 50 mm upstream
The distance between SDC1 and SDC2 becomes 80 mm….
New SDC2 position

5. SDC1 position
Original SDC1 position
The distance between SDC1 and SDC2 is too small to install SP0.
⇒To change distance in which SP0 can be installed.
⇒Distance ~160 mm
New SDC1 position

6. SP0 position (cross section)
Interference (just 1 layer)

7. SP0 position (side view)
Very tight space for installing SP0 !

8. HBJ position (side view)
Not to insert SDC1 into Hyperball-J frame
⇒The position of HBJ frame becomes more upstream.

9. HBJ position (side view)
To insert SDC1 into Hyperball-J frame
⇒To install SDC1 as shown in the picture

10. Information1 Target⇔SDC2 : 575→525 (-50 mm)
SP0 space : 159 mm
SDC1⇔SP0 (between surface) : 7 mm
SDC2⇔SP0 (between surface) : 7 mm
Target position : Original→Realistic : -90 mm
Target position w/ HBJ frame: -130 mm
⇒less than -100 mm.

11. Acceptance by changing target position
Center : 112 msr
Down : 118 msr
Up : 107 msr
(up to 20 degree scattering angle)
⇒ ~0.5 % / 1 cm
○ : Target center
× : Downstream 100 mm
□ : Upstream 100 mm

12. Interference of SKS magnet refrigerator
Need to change the SP0 magnetic shield

13. W/ Beam line elements (FF+600mm)

14. W/ Beam line elements (FF+0mm)

15. Information2 Target ⇔Q magnet : 1900 mm
Q magnet⇔BDC3 : 400 mm (center)
Q magnet⇔BDC4 : 800 mm (center)
BDC4(surface)⇔Target : 1056 mm
BDC4(surface)⇔HBJ (surface) : 621 mm
BDC4(surface)⇔SDC1(surface) : 1272 mm

16. Summary
The position of the target has to be changed to the upstream direction.
Less than 100 mm
Space between beam line and Hyperball-J frame is large enough.
FF+600 mm is little larger than optimum space ?

17. Plan Frame design + Detector position arrangement
SP0 design (by Otani)
4He target
Arm design, full set size, etc.
SDC2 repair and PreAmp position arrangement