Transcript Diodes
Summer Student Presentation Radiation Monitoring with commercial p-i-n diodes BPW34F Summer Student Project of Kim Temming Supervisors: Michael Moll Maurice Glaser Friday, 3rd of September By Kim Temming 1 Outline purpose of my project diode BPW34F / BPW 34 how to measure radiation with this diodes? history of my measurements irradiations first setup measurements / results problems new setup measurements first results problems first conclusions outlook Summer Student Presentation Kim Temming 2 Purpose of my Project investigate the possibility to use commercial BPW 34 p-i-n diodes as dosimeters for LHC experiments and irradiation facilities advantages commercial product: low costs (1.60 €) robust and easy to handle large fluence range (1012 – 1015 p/cm2) measuring NIEL (displacement damage) disadvantages needs qualifying temperature & fluence dependence annealing readout scheme commercial product (no influence on production) Summer Student Presentation Kim Temming 3 Diode BPW34F / BPW34 commercial SI-pin-diode / cheap BPW34 photosensitive from 400nm to 1100nm (BPW34F: 950nm) applications: IR remote controls photointerruptors control and drive circuits BPW34 - photosensitive area + BPW34F Summer Student Presentation Kim Temming 4 How to measure radiation? increase of voltage with fluence for constant current when biased in forward direction Summer Student Presentation Kim Temming 5 My Work: Irradiations 102 diodes were irradiated with 24 GeV/c PS proton beam 50 BPW34F from USA 1.0 E15, 0.5 E14, 0.3 E14, 1.0 E14, 0.5 E13, 0.3 E13, 1.0 E13, 0.5 E12, 0.3 E12, 1.0 E12 (all in p/cm2) 22 BPW34F from MALAYSIA 1.0 E15 ppcm2, 1.0 E14 p/cm2 BPW34 Siemens, BPW34 Osram and BPW34FS each 5 pieces 1.0 E13 p/cm2 each 5 pieces 1.0 E14 p/cm2 irradiations successful in limits of 20% discrepancies to wanted fluence (+ca. 8% errors on values) Summer Student Presentation Kim Temming 6 First Setup aluminium box / completely dark (diodes are sensitive to daylight!) Keithley 2400 set current / read voltage sensor for temperature inside box / 2 cm beside diode sensitivity: 0.1 degree celsius labview program option for constant current option for pulsed current displays graph: voltage time Summer Student Presentation Kim Temming 7 Measurements / results first setup VI measurements of all samples before irradiation current between 0.1 A and 1 mA results of VI measurements before irradiation: nearly all samples show same characteristic all differences between samples become larger with higher current diodes before irradiation 0.6600 voltage (V) samples from Siemens: old (some years) vary more than 20% samples siemens 0.5600 U at 100nA (V) 0.4600 U at 1muA (V) U at 10muA (V) 0.3600 U at 100muA (V) 0.2600 U at 1mA (V) 95 88 81 74 67 60 53 102 43 36 29 22 15 8 1 0.1600 sample number Summer Student Presentation Kim Temming 8 Measurements / results first setup dependence of the voltage on readout frequency and readout pulse length 10 samples together irradiated with 1.0 E14 protons/cm2 applied current: 1 mA pulse length varying between 1 ms and 1 s pulse to pulse time between 60 s and 3 s Results of dependence on readout frequency & pulse length Summer Student Presentation value voltage dependent on the number of diode different colors show different pulse-to-pulse time voltage (V) not very sensitive to pulse length (except of constant current) not at all sensitive to time between pulses but differences of more than 20 % between the different diodes 11.5 11 10.5 10 9.5 9 value voltage delay 60 s value voltage delay 10 s value voltage delay 3s 13 15 17 19 number of diode Kim Temming 9 Measurements / results first setup dependence on readout current ONE diode irradiated with 1.0 E14 protons/cm2 pulse to pulse 3 s, pulse length varying current varying between 1 A and 100 mA Results of dependence on readout current 18.1 16.1 14.1 12.1 10.1 8.1 6.1 4.1 2.1 0.1 (voltage <-> applied current) for different pulse lengths 18 0.001 mA 0.01 mA 0.1 mA 1 mA 10 mA 100 mA 16 voltage in V voltage in V voltage to pulse length 14 pulse length 1 ms pulse length 10 ms pulse length 100 ms pulse length 1000 ms pulse length 3000 ms (cc) 12 10 8 6 4 2 1 10 100 1000 10000 pulse length in ms Summer Student Presentation 0 0.001 0.01 0.1 1 10 100 current in mA Kim Temming 10 Problems of first setup diodes are very sensitive to temperature measured voltage depends very much on the temperature of diode temperature is measured 2 cm away from diode / isolated by plastic and air possible sources of temperature differences changes of room temperature (air condition!) touching of diodes opening of box necessary to control temperature of diode very exactly Summer Student Presentation 22.4 temperature another possible explanation: diodes show peltier effect cooling down by applying current temperature - voltage 22.2 22 21.8 21.6 21.4 9 Kim Temming 9.5 10 10.5 voltage 11 11.5 12 11 New setup peltier element below socket of diode regulates temperature of diode to exactly 19.3 0.01 degree celsius temperature read out by small temperature sensor (operated with Keithley 2410) readout of diode still with Keithley 2400 temperature displayed on web with webDAQ/100 Summer Student Presentation Kim Temming 12 Measurements with new setup ONE diode irradiated with 1.0 E14 protons/cm2 always same end value with constant current first no room temperature effects (outside box) visible because of the good temperature shielding over night / weekend measurements irradiated diode non irradiated diode very temperature stable resistor measurements: applied current: 100A, constant current temperature measured inside and outside the box with 2 digits voltage measured with labview-program and Keithley 2400 Summer Student Presentation Kim Temming 13 First results (new setup) irradiated diode: voltage still depending on temperature but very sensitive not irradiated diode: same results but less amplitude 1 k Ohm resistor Summer Student Presentation Kim Temming 14 Problems of temperature / Keithleys not completely clear yet: effect of temperature in diode? effect of room temperature in Keithleys? limit of keithley accuracy! Summer Student Presentation Kim Temming 15 First conclusions before irradiations: all diodes very close together, only few discrepancies on readout voltage after irradiation: diodes show discrepancies of up to 20% on readout voltage diodes very temperature sensitive temperature needs to be controlled best readout scheme: current: 100 A pulse length: 1 ms pulse to pulse: ~ 3s (not very sensitive) Summer Student Presentation Kim Temming 16 Outlook continue measurement more different devices (to get statistics) more sensitive temperature control dependence on the readout temperature for fluences 1.0 E12...E15 p/cm2 from –10 C to +30 C dependence on the fluence 1.0 E12 p/cm2 up to 1.0 E15 p/cm2 annealing of samples in oven 40, 60. 80, 100 degree celsius End Summer Student Presentation Kim Temming 17