Kentech Instruments Pulse Chopper System Manual Download Page 11

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Kentech Instruments Ltd., Unit 9, Hall Farm Workshops, South Moreton, Didcot, Oxon, OX11 9AG, U.K.

10th. July 1999

Figure 6

The head connected for testing

Figure 7

Gating off and looking for good extinction. Tested with a Kentech
Gated Optical Imager with a 1ns gating module

Summary of Contents for Pulse Chopper System

Page 1: ...shops South Moreton Didcot Oxon OX11 9AG U K 10th July 1999 Unit 9 Hall Farm Workshops South Moreton Didcot Oxon OX11 9AG U K Kentech Instruments Ltd Pulse Chopper System J99 10th July 1999 PLEASE REA...

Page 2: ...capacity is small careless use could result in electric shock It is assumed that this highly specialised equipment will only be used by qualified personnel The manufacturers and suppliers accept no re...

Page 3: ...ING THE TIMING OF THE CHANNELS 7 6 0 MOUNTING THE CELLS 9 6 1 PHYSICAL MOUNTING 9 6 2 ELECTRICAL MOUNTING 9 6 3 DC CONNECTIONS 9 Figure Captions Figure 1 The front panel 5 Figure 2 A plot of DC transm...

Page 4: ...ontrol controls the pulse voltage in approximately 20 volt steps from 210 volts to 470 volts All four channels are adjusted together This is effectively the voltage into a 50 load By mismatching the e...

Page 5: ...amplitude polarised at 90 to each other These travel at slightly different speeds in the excited medium and emerge with a relative phase shift of 2 In the unexcited medium there is no relative change...

Page 6: ...s easily obtained from the transmission obtained when the voltage is removed to the transmission when the voltage is applied Note that some power supplies will not discharge the cells when they are tu...

Page 7: ...ming 5 Once all the timings are noted use one in approximately the centre of the range as a reference and adjust all the others so that they are the same see section 5 3 Note the unit supplied is set...

Page 8: ...ot Oxon OX11 9AG U K 10th July 1999 Figure 4 Locating the timing adjusters View with bottom cover removed There are four white adjusters The adjuster at the top of thispicture closesttothe bottom pane...

Page 9: ...ght improve the risetime or not The further apart the cells are mounted the greater the timing for the second cell will have to be adjusted as it will have to be driven slightly later It is possible t...

Page 10: ...s Ltd Unit 9 Hall Farm Workshops South Moreton Didcot Oxon OX11 9AG U K 10th July 1999 1 11 12 13 14 15 16 17 18 19 2 3 4 5 6 7 8 9 10 Figure 5 Output pulse shape one of four channels 100voltsperdivis...

Page 11: ...Hall Farm Workshops South Moreton Didcot Oxon OX11 9AG U K 10th July 1999 Figure 6 The head connected for testing Figure 7 Gating off and looking for good extinction Tested with a Kentech Gated Optica...

Page 12: ...uth Moreton Didcot Oxon OX11 9AG U K 10th July 1999 Figure 8 Testing for long term extinction Showing that reasonable extinction persists to 30ns Figure 9 The gate off fall time Measured with a Kentec...

Page 13: ...13 Kentech Instruments Ltd Unit 9 Hall Farm Workshops South Moreton Didcot Oxon OX11 9AG U K 10th July 1999 Figure 10 The gate off fall time is measured at 728ps...