# Presentation: 559261

## Preradiator

- Toshio Numao
*TRIUMF*

- May 18, 2004

## Scope of subsystem

- Measures -ray direction and energy loss
-     to constrain the kinematics of a kaon decay.
-           Chamber/Scintillator system
- Provides photon veto.
-           External PV
- Trigger source for positive identification
-     of signals.
-           Scintillator segmentation

## Specification from Physics

- Energy resolution  at 1GeV:                          2.5 %
- Timing resolution :                                       200 ps
- Position resolution :                                       5 mm
- Angle resolution of  rays :                       25mr
- Large total radiation length :                           2
- As thin as possible :                                         1 m
- Between 2 measurements :                           0.03 r.l.
- Well segmented :                                       4 x 10/plane
- All photo-tubes can easily be accessed for maintenance or have enough redundancy in readout.

## Mechanical specification

- Consists of 4 3.5x3.5m2 (2x2m2 active region) quadrants.
- Each quadrant has 8 modules (construction unit).
- A module has 8 alternating X,Y readout chambers,  9 scintillator, and thin radiator (Cu and Al) planes.
- Each combination (scintillator+chamber+radiator)
-       is 0.03 r.l. thick.
- A photon veto system that is mounted in the same support structure surrounds the active region of
-       the preradiator.
- Chamber electronics will be mounted outside the
-       photon veto system.
- All photo-tubes can easily be accessed for maintenance or have enough redundancy in readout.

- BEAM

## Preradiator Module Design (bottom quadrant)

- Front view

- Side view

- PMT

- Electronics

- Support stand

- Scintillator

- Chamber (X layer)

- Chamber (Y layer)

- WLS fiber

- Outside photon veto

- K0 beam

**Adapter**
**(16ch)**

- Cathode strip

**VETO**

**Anode Readout**
**(32 Cards) **

- Anode wire

- HV &
- Signal Gnd return

- Cathode Gnd return

***Computer***
***Farm***

**AMT-3**

**Cathode Readout **
**(32 Cards) **

- Anode/Cathode coaxial cable chamber
- Assembly (95Ω-Graphite low noise 1m)

**Module box (8 chambers, 9 Scint.)**

**Cathode**
**Adapter**
**(16ch)**

**VETO**

**Faraday Cage**
**(module structure)**

**Remote HV Control 16x12 HV**

**Module**
**Collector**
**(1 card)**

**NIOS**

- Slow Control
- Link (ETH)

- CTL

- System
- CLK

_**ETH Link**_
**(32 links)**

**NIOS**

**NIOS**

**Chamber**
**Collector**
**(8 cards)**

- Card Level

- Crate Level

- Module Level

**(96ch)**

**(96ch)**

**(4 links)**

**(4 links)**

**(8 links)**

**ADC**

**FPGA**

**FPGA**

**Current status of the readout system**

## Present status

- Scintillator     6-hole scintillator has been produced successfully.
-                                     Surface quality and dimension stability are being
-                                      improved.
- Chamber        5 prototype I, 2 prototype II, and 1 prototype III chambers
-                                      were constructed. 200-m resolutions have been obtained
-                                      for anode and cathode readouts. Tests for large angle track
-                                     are in preparation.
- Mechanical    A full scale mock-up is being constructed for the tests of
-                            mechanical stability. Stress calculations have been done.
-                            Cooling system is being designed.
- Electronics     Pre-amps for anodes and cathodes are being tested with
-                                     prototypes.  Cables and HV cards have been prototyped.
-                                     A prototype cathode readout board is being manufactured.
-                                     A design of a prototype anode board has been done.
- Photon veto   The default design is that of Calorimeter.

## Progress and milestones

-  3/2004    Complete prototype IIIc for cathode readout system tests.
-                   Full size mechanical mock-up.
-  5/2004    Complete large angle cathode resolution tests.
-                   Readout system integration prototype.
-  12/2004  Scintillator production for a module.
-  8/2005    Complete first chamber.
-  1/2005    Complete first prototype  module.
-                    2x96 channel electronics systems.
-  9/2005     Module test and analysis.
-  3/2006     Start chamber, scintillator production.
-  8/2006     First production module.
-  9/2008     Finish production and installation.

- Milestones

- Achieved

-  10 prototype chambers constructed. 200m resolution obtained.
-   Extruded scintillator successfully manufactured and tested.
-   Front-end electronics have been tested. HV board and cables prototyped.
-   Simulation for mechanical support successful. Heat expansion and other
-    issues developed.

## Changes from the last TDR

- Scintillator
-             thickness                        8 mm  9 mm
-             fiber  readout                 grooves on surface  holes
-             readout                           single-end  2-end
-             layout                             XYZ  XY
- Chamber                                fins  no fins
- Prerad/support                       fixed  independent
- Beam hole                             notch  horizontal slit
- Photon veto                           Pb on each layer separate
- Cathode readout                    SCA  fast ADC
- Number of channels
-             anodes                            84k  98k
-             cathodes                         64k  98k
-             pmt                                 1.2k  2.5k

## Justification and constraints

- Separate PV
-       Uniform energy calibration.
-       Better energy resolution.
-       Enough radiation length.
- Two end readout
-       More light output.
-       Provides position info along the fiber.
-       Twice more PMTs  redundancy in PV.
-       Less acceptance around the beam.
- More electronics
-       More acceptance, especially if PV works as Cal.
-       Higher cost? Maybe not.

## Justification and constrains

- No fin geometry (pros)
-           No heat expansion diff.
-           Mechanical stability.
-           Simplifies construction.
-           More cathode charge.
- No fin geometry (cons)
-           Longer drift components.
-           Hanging wire ?
- One prototype constructed
-       and two more to come for
-       tests of basic characteristics.

## Open questions

- Simulation
-            Does the concept of a  separate PV work?
-              Can the PV be used as a calorimeter?
-              Wider horizontal cut-off in the beam region okay?
-              Does a thicker PR cause a wider shower?
-              De-multiplex all scintillators for neutron rejection?
- Access
-            How often do we need to access the PMTs?
-              How much redundancy is good enough?

## Integration issues

- PMT readout and “500 MHz” digitizer:
-          location...
-          trigger electronics?
- Air conditioned tent.
- Crane access: Conflicts with PV and Calorimeter?
- Support space: Conflicts with PV and Calorimeter?
- Access: Conflicts with PV and Calorimeter?
- Interference with the vacuum chamber
-        Position monitoring at the time of installation?

## Utility requirements

- Power for high-current LVs, and HVs
- Proper ground
- Cooling system
- Dry, cool  “air”
- Air conditioning

## Space requirements

- On the experimental foor
-       (module width) x 4 + 2m  16m
-       70 racks for LV and HV PSs
- Place for final assembly
-       Relatively clean and air conditioned
-       with crane access, and high enough entrance
-       and ceiling (5 m).
- Place for testing
- Storage space
- Place for flipping
-       6m x 6m (minimum)

## Resouces

- D. Bryman        UBC                           co-spokes person
- T. Numao          TRIUMF                    coordinator
- R. Henderson    TRIUMF                    mechanical
- N. Khan             TRIUMF
- C. Lim               TRIUMF
- P. Amaudruz     TRIUMF                    electronics
- J.P. Martin         UOM
- C. Ohlmann       TRIUMF
- M. Constable     TRIUMF
- R. Bula              TRIUMF
- J. Cresswell      TRIUMF
- J. Ives                UBC                           student
- S. Begin             UBC                           student
- Need a designer and a mechanical engineer.

## Safety

- Chamber gas:Ar(50)+Ethane(50):flammable
- Dry “air” (N2) to chamber perimeter:
- Cooling: High pressure “air”
- Chamber HV: concealed
- LV high current: each board/crate with fuses.
- Mechanical safety
-      Stability
-      Access from bottom
-      Crane access
- Scintillator: combustible
- Other materials (cables,...)

## Crane requirement

- There are 32 modules (mechanical unit):
-  Size of module: 350-370 x 350-370 x 15 m.
-  Weight of module:  1.5 t.
-  At the time of installation,
-        top and bottom modules will be carried
-        by a crane to the pit; either fixed onto the
-        support structure.
-  At the time of storage or testing, crane access
-        is desirable.