# Presentation: 268677

## Mu2e:How PPD is going to build this Experiment (or at least part of it)

- R. Ray
- Mu2e Project Manager
- 10/20/08

## Mu2e is a search for lepton flavor violation.  This means that one starts with one type of lepton (a muon in our case) and ends with a different type of lepton (electron) and there are no neutrinos around to balance the equation.
This can only happen at an observable rate if it is induced by new physics outside the Standard Model.

- Mu2e is a search for *lepton flavor violation*.  This means that one starts with one type of lepton (a muon in our case) and ends with a different type of lepton (electron) and there are no neutrinos around to balance the equation.
- This can only happen at an observable rate if it is induced by new physics outside the Standard Model.

*****N **** e****N*
*The muon converts to an electron in the field of a nucleus and emits a ~105 MeV electron. *

## Production

- Solenoid

- Transport
- Solenoid

- Detector
- Solenoid

- Proton
- Target

- Target
- Shielding

- Muon Beam
- Collimators

- Tracker

- Calorimeter

- Pions

- Electrons

- Muons

- Muon
- Stopping Target

- Particles are collected, transported, and
-  detected in solenoidal magnets

## Places where PPD could help

## R&D - L tracker prototype

- 5 mm diameter, 25 m thick walls, 2.6 m long.
- Operates in vacuum.
- Need to test straw deformation, leak rate, minimize noise on resistive pad readout,
- design low mass, low profile support structure/gas manifold and cabling scheme.
- Goal is to keep material out of path of electrons.

- Straws run in this direction

## Cosmic ray veto R&D

- Background from cosmic rays can severely limit the sensitivity of the experiment.  The goal is to reduce the cosmic ray flux by a factor of 10000 by both active and passive mechanisms.
- Surround Detector Solenoid with shielding and MINOS style extruded scintillator planes.

- We want to build a multi-layer
- test array to study light output
- and efficiency.

## Mechanical Designs

- Muon stopping target
- 17 disks, 0.02 cm thick spaced 5 cm apart along the detector solenoid axis.  Radii range from 8.3 cm upstream to 6.53 cm downstream.  Supports have to be designed very carefully to avoid backgrounds and e energy loss.
- Muon beam stop
- Absorbs energy of beam particles
- (mostly  and e) that reach the end
- of the detector solenoid while minimizing
- background to detector elements from 
- decays and capture and bremsstruhlung
- from e.  Complicated design of lead,
- stainless steel and polyethylene.

## Mechanical Designs (cont.)

- Absorbers
- Moderate protons and neutrons to reduce
- 	backgrounds and detector rates.
- Boron or lithium loaded polyethylene.
- Calorimeter mechanical support and cooling system

## Mechanical Designs (cont.)

- Detector support structures
- Three separate track systems are needed
- 	in moving the detectors and the rear
- 	closure of the cosmic ray shield.
- The support structure is similar for all three
- 	carts: a rigid rib-and-truss cage surrounding
- 	the detectors and riding on the rollers.
- Tracker support carries very little weight but must take the force from tensioning of the straws (FEA calculations needed).
- Calorimeter support carries 2.4 tons.
- Target/absorber cart carries very little weight but is 3.5 m long.
- Need a survey scheme.

## Electronics	

- Electronics

- Requirements:
- Amplitude and time information for all hits.
- Large dynamic range, to accommodate both electron hits and high ionization caused by low-energy protons.
- Low power consumption for the components operating in vacuum.
- Radiation hardness does not appear to be a concern.
- Limited space available.
- High reliability.
- Low cost, large channel count.

## Tracker Electronics

- Amplifier-shaper-discriminator chip required for front end of straw tubes.
- ATLAS ASD chip for thin gap chamber is a good starting point.
- Components mounted on support structure at large radius.
- Coolant flows through pipes attached to the support structure.
- Biggest concern is noise on the pad readout.
- Multi-channel pipelined, dead-timeless ASIC at the front end of the detector to read, digitize, and buffer hits.
- Functionality similar to the BaBAR ELEFANT chip.

## Calorimeter Electronics

- ~1800 crystals, each read out by 2 APDs
- Signals are amplified and shaped before being sent to calorimeter digitizing modules (CDM) where they are digitized.
- Command and control structure must also be developed.
- CDMs would also be used for cosmic ray veto.

## Slide 13