Who am I?

●Daniel John Kirby●Carnegie Mellon Physics Class of 2013●In Hall A June-July 2012

Task: Implement systems to make FASTBUS readout faster (using

CODA)

The Goal: Reducing Deadtime

Main Sources of Deadtime Conversion

Readout

Mathematical Model

Tasks to Implement

Multiblock Readout

SFI sequencing

Event Blocking and Parallel Buffering

Module Buffering

Sparsification

Library Implementation

Sparsification

Event Blocking Illustrated

Thanks to Dave Abbott for this idea.

Increasing the Buffer Depth

Parallel Buffering

Split TDC buffer into two distinct buffers.Readout and trigger acceptance can happen

concurrently

Sequential vs. Parallel Buffering

Looking Forward: Parallel Module Buffering

Reduces effective trigger rate.Thanks to Igor Rachek for original concept.Thanks to Bryan Moffit for help improving this diagram.

Effect of Module Buffering

Acknowledgements

Once again I'd like to extend special thanks to:

Bogdan Wojtsekhowski Bryan Moffit Dave Abbott Igor Rachek

Magnetic Field in Gas Cherenkov Counter By: Austin Milby, Menchville High School, class 2013

Physics is COOL!

Magnetic Field in Gas Cherenkov Counter Introduction

WHAT: Shielding of PMT’s from magnetic field generated by BigBite

WHY: Magnetic field can cause electrons in PMT to change direction and bend away from dynodes, resulting in skewed data

HOW: By implementing a magnetic shielding box for use in the Cherenkov Counter, we can reduce the presence of the magnetic field around the PMT’s which will result in more accurate data

Study done by SLAC found that Y-orientation of PMT is most severely affected by magnetic field.

Need field to be bellow 1 Gauss!

Detector of the BigBite spectrometer in A1n experiment

I am working with magnetic shielding of the PMT for the Gas Cherenkov counter

BigBite magnet and the field components

Field components are of 5-10 GaussAt PMT the field need to be reducedto the level of 0.5-1 Gauss

Bz component, Gauss

By component, Gauss

Bx component, Gauss

-100cm 100cm

-100cm 100cm

-100cm 100cm

7

2

-2

10

5

1

-1

-2.5

-4

(through center of Cherenkov Counter)

The layout of the PMTs in the counters

Design of Magnetic Shielding Box being considered for use in detector. It will be placed in green area on picture.

Mirror

PMT face

Center of counter where data on previous slide was obtained

BigBite Magnet and the Field Components (2)

(Data taken along purple line)

Bx component, Gauss

By component, Gauss

Bz component, Gauss

(Along surface of PMTs)

100cm -100cm

100cm -100cm

100cm -100cm

Magnetic Shielding

Black box outlines location of PMTs in shielding box.

PMT faces

NOTE: Data taken with external field of 20 Gauss and current in compensation coil set at 120 amps