Fast Timing in Cosmic Rays

Simon Swordy - November 18th

Above the atmosphere

• mass identification

• trigger and charge measurement

• calorimeter albedo rejection

Ground based

• dual focus imaging systems

Mass id science

• Be9/Be10 - age of cosmic rays should show time dilation effects which map out the density of material traveled versus time. Need lorentz factors above ~2.

• He3/4 - material traveled as a function of lorentz factor -> required to find source energy spectra of He

• antiprotons - what do these do at high energy?

• anti-deuterium - is there any of this?

~3m

What is the maximum detectable for a TOF system with resolution t and a separation of 3m?

t(ps) max

100 7.1

30 12.9

10 22.4

3 40.3

• probably interesting for Be9/10 and anti-deuterium

• not much good for He3/4 (need 100 or so)

• works in a region where there are no good cherenkov radiators (n>1.01 n<1.1)

Calorimeter albedoproblem

CREAM-2004

albedo time ~several ns

pixel detectors would be muchbetter than paddles because oftransit time in paddles

Dual focal length cerenkov imaging

Primary, spherical1m dia, 4m focal

Detector,26x26cm1600 pixels

Fresnel lens1m focal

3m

1m

~ 18ns delay between images

- TrICE (Track Imaging Cherenkov Experiment)

U. Chicago - ANL

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50

1.5

3

4.5

6

7.5

9

10.5

12

13.5

15

Emission Angle (deg)

Tim

e D

elay

(ns)

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.50

1.5

3

4.5

6

7.5

9

10.5

12

13.5

15

Emission Angle (deg)

Tim

e D

elay

(ns)

Size of Direct Cherenkovspot -> nucleus Z

• Dual focal length system• 1st image wide angle includes shower-trigger• 2nd image higher resolution finds direct Cherenkov component -> ns resolution would be useful here

HOW MUCH?

For a NASA experiment on balloons 1 detector plane of 1mx1m could beup to $250k -> $25 per cm2

For an imaging cherenkov camera 0.6m x 0.6m could be $300k -> $80 per cm2

Probably needs to get below $100 per cm2 to be a contender.........