14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 1

Irradiation with Protons -Irradiation with Protons -IQC KarlsruheIQC Karlsruhe

IEKP - Universität Karlsruhe (TH)

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 2

Isochroncyclotron in KarlsruheIsochroncyclotron in Karlsruhe

• 26 MeV protons

• Frequency:

~33MeV

• Accessible

within 2 days

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 3

Irradiation AreaIrradiation Area• Cooling with Nitrogen

gas down to -50°C• Initial positioning by

laser pointer• Scanning with 1mm

row steps (10cm/s)• Used proton current:

2 A• Irrad. of 120x120mm2

up to 1e14 p/cm2

takes 20min

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 4

During Irradiation ...During Irradiation ...

Cold box with proton beam spot on mylar window

Scanning speed up to 250 mm/s !

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 5

Homogeneity of ScanningHomogeneity of Scanning

Scan Area

Area of Interest

Autoradiography picture

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 6

Fluence EstimationFluence Estimation

• Beam current I in p/s

• Calculate ratio of hits inside homogeneous area to total hits

• F = I * * t / Ahomogene

• Get time t for irradiation

• Adjust speed to have integer no. of scans

Teststructure

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 7

Fluence MeasurementFluence Measurement

• Ni foils behind teststructures in homogeneous area• Measure specific activity of 57Ni line with Ge-

Spectrometer• Extrapolation to activity at 3.77 days after irrad.

(T1/2 = 35.6h = 1.483 days = 2.14 days)

• Calibration factor for 26 MeV protons:19.28 kBq cm2 / mg Ah

• 1 Ah = 22.5e15 protons

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 8

ComparisionComparision

1 2 3 40

2

4

6

8

10

12

14F

luen

ce [1

e14

p/cm

2 ] Ni analysis Estimation from BS2 current

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 9

Speed CalculationSpeed Calculation

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 10

Current ControlCurrent Control

• Beam current monitored during irradiation

• Data saved to disk

• On-line integration of current

• Beam and scanning automatically stopped if

current out of limit (e.g. 10%)

• Insert aperture to get more stable low current

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 11

Biasing schemeBiasing scheme• After 10 years LHC we expect a current of upto 1µA per strip at 1M 1V potential at p-implant

• Bias of 1V during irrad. and both AC and biasring on ground gives 1V over diel.

• Used bias voltage for safety reasons (voltage drop in power lines) : 12 V

14.3.2002 1.Irradiation Workshop - Karlsruhe

A. Dierlamm, IEKP 12

Next IrradiationsNext Irradiations

• Hybrid• Optohybrid• Module

• We will provide the hybrids with power,

clock, I2C-pulses and reset.• The module will be under bias.