Difference between revisions of "Fixed array: design"

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= Light guides for broadband hodoscope =
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= Scintillators for broadband hodoscope =
  
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material: UVT acrylic <br>
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material: EJ-228 <br>
  
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length: 150 mm <br>
+
height: 33mm (3mm slotted into bottom face of LG)<br>
 
thickness: 6mm <br>
 
thickness: 6mm <br>
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width: 22x 22mm, 18x 16mm, 24x 10mm, 185x 8mm
+
width: 22x 21mm, 18x 16mm, 24x 10mm, 17x 8mm, 58x 5mm, max. 36x 4mm, max. 67x 3mm <br>
 +
(the max. numbers account for positioning of the microscope with coh.edge at 9.1 to 7.9 GeV).
  
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=== Concept: ===
+
= Light guides for broadband hodoscope =
  
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* The counters are positioned vertically, hanging from top with 30mm high scintillators (SC) centered at the focal plane.
+
(update 4/22/2013)<br>
  
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* The 15cm long light guides (LG) are fixed by two horizontal comb-like aluminum bars, i.e. two bars with comb-like slits of 8mm width separated vertically by 10cm, in which the wrapped LGs are (gently) pushed. The slits are cut away at such angles that the SCs face in the direction of the electron trajectory.
+
material: UVT acrylic <br>
  
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* To ensure an accurate angular alignment of the SCs, the LGs have the same thickness (6mm) as the SCs. This also simplifies also the control of the gluing process because these 2 faces are visible while pressing the SC onto the LG. SCs of larger width (22, 16, 10, 8mm) will fit exactly onto the LG's face, the smaller SCs (5, 4, 3mm) will be centered onto the 8mm wide face of the LG by means of a mask.
+
cylinder (diameter: 22.2mm, length: 100 mm) <br>
 +
(6mm wide and 3mm deep slot on bottom face)<br>
  
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* LGs with larger cross section than the SC are more difficult to make light tight at the corners without using many layers of tape, which might obscure the upper part of the SC.
+
=== Concept: ===
  
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* The upper 3cm of the LGs are cylindrical tops of 1" (2.54cm) diameter. The LG bars will be fixed in a 3mm deep slot in the center of the bottom face of the cylindrical top. The cylindrical top will lay (loosely) on the comb-like support, thus prevents the counters to sag.
+
* The counters are positioned vertically, hanging from top with 30mm high scintillators (SC) centered at the focal plane.
  
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* The top face of the LG will be connected to the photocathode of the 1" PMT (Hamamatsu R9800) via a silicone cookie. PMT and cylindrical top of the LG will be covered by a 0.25mm thick mu-metal foil.
+
* NEW: 10cm long light guides (LG) are fixed by a nylon collar bolted to a horizontal 1/2" aluminum plate. The screw holes in the al. plate are drilled at positions that ensure that the SCs face in the direction of the electron trajectory. The bottom face of the LG is slotted (width 6mm) to fit the thickness of the SC (ensuring that the SC are accurately glued to the LG).
 +
 
 +
* The top face of the LG will be connected to the photocathode of the 1" PMT (Hamamatsu R9800) via a silicone cookie (or air gap). PMT and top part of the LG will be covered by a mu-metal cylinder.
  
 
* The back face of the PMT should be covered by a light tight paint such that voltage divider and preamplifier do not have to be tightly covered.
 
* The back face of the PMT should be covered by a light tight paint such that voltage divider and preamplifier do not have to be tightly covered.
  
 
<br>
 
<br>
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[[File:counters6.73-8.0GeV.gif]]
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[[File:pmt.gif]] &nbsp; &nbsp; [[File:LG+collar.gif]]
 +
 
 +
<br>
 +
[[File:Ncounters6.73-8.0GeV.gif]]

Revision as of 11:37, 22 April 2013

Scintillators for broadband hodoscope

material: EJ-228

height: 33mm (3mm slotted into bottom face of LG)
thickness: 6mm
width: 22x 21mm, 18x 16mm, 24x 10mm, 17x 8mm, 58x 5mm, max. 36x 4mm, max. 67x 3mm
(the max. numbers account for positioning of the microscope with coh.edge at 9.1 to 7.9 GeV).

Light guides for broadband hodoscope

(update 4/22/2013)

material: UVT acrylic

cylinder (diameter: 22.2mm, length: 100 mm)
(6mm wide and 3mm deep slot on bottom face)

Concept:

  • The counters are positioned vertically, hanging from top with 30mm high scintillators (SC) centered at the focal plane.
  • NEW: 10cm long light guides (LG) are fixed by a nylon collar bolted to a horizontal 1/2" aluminum plate. The screw holes in the al. plate are drilled at positions that ensure that the SCs face in the direction of the electron trajectory. The bottom face of the LG is slotted (width 6mm) to fit the thickness of the SC (ensuring that the SC are accurately glued to the LG).
  • The top face of the LG will be connected to the photocathode of the 1" PMT (Hamamatsu R9800) via a silicone cookie (or air gap). PMT and top part of the LG will be covered by a mu-metal cylinder.
  • The back face of the PMT should be covered by a light tight paint such that voltage divider and preamplifier do not have to be tightly covered.


Pmt.gif     LG+collar.gif


Ncounters6.73-8.0GeV.gif

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