Emittance meter with CEM

Initially we had an Allison type emittance meter

s

-100V

SCANNER CURRENT

± V

gL

beam

L = 70 mmg = 4 mmV = ± 1000 V (KEPCO)

Limitations• Could not take a scan for beam currents

below 1 nA• between 1-3 nA one had to use reverse

bias to take a scan.

Upgrade: CEM incorporation

Two modes of operation• Channeltron: Low beam intensity~10pA• Faraday cup: Beam intensity > 1nA

L = 50 mmg = 2mmV = ± 1000 V (KEPCO)

Emittance meter with CEM

Emittances at low intensities:

116Cd at 20 kV Intensity= 15 pA, Scalar time = 0.25 s

e = 3.86 mm mrad

225Ra at 20 kV Intensity=13000 cps, Scalar time= 2s

e = 4.2 mm mrad