Combining the strengths of UMIST and The Victoria University of Manchester Conny Hansson, Supervisor: Prof. Robert. J. Cernik Funded by EPSRC Materials Science Centre University of Manchester

Combining the strengths of UMIST and The Victoria University of Manchester Groups Advanced Characterization Techniques Group School of Materials, University of Manchester The development of the rapid tomographic energy dispersive diffraction imaging system, rTEDDI for short. The HEXITEC consortium ( A collaboration between Manchester University, Durham University, Surrey University, Birkbeck College and the Rutherford Appleton Laboratory The development of materials, interconnection technology and readout for imaging CdZnTe detectors

Combining the strengths of UMIST and The Victoria University of Manchester What is rTEDDI Limiting factors of the current rTEDDI system The ERD2004 detector Measurements and Results Consequences of the results and the development of the HEXITEC detector

Combining the strengths of UMIST and The Victoria University of Manchester What is rTEDDI ?

Combining the strengths of UMIST and The Victoria University of Manchester - T omographic E nergy D ispersive D iffraction I maging Single Voxel TEDDI Disadvantages: Long exposure times (exceeding16-20Hrs) Examples of 3d TEDDI images Barnes et al (Birkbeck) Cernik et al (Manchester)

Combining the strengths of UMIST and The Victoria University of Manchester rTEDDI realised 2 MK 1.2 Collimator Si Detect or Sample Sample holder and moving stage White beam Thin fan beam MK1.2 Femto-second laser drilled W collimator array coupled with a pixelated (300µm pitch) energy resolving detector (ERD2004) L. Tunna, P. Barclay, R.J. Cernik, K.H. Khor, W. ONeill, P. Seller, Meas. Sci. Technol. 17 (2006) P. Seller, W.J. Gannon, A.D. Holland, G. Iles, B.G. Lowe, M.L. Prydderch, S.L. Thomas, R. Wade, SPIE, EUV, X-ray and Gamma-ray Instrumentation for Astronomy IX, San Diego, CA, USA, (1998) July, vol

Combining the strengths of UMIST and The Victoria University of Manchester rTEDDI: proof of concept Obtained at Stn. 7.6 SRS Daresbury Labs. For thin samples R.J. Cernik, K.H. Khor, C. Hansson, J. of the Royal Soc. Interface 5 (2007) Useful areas: strain distribution scanning material identification (spatially resolved)

Combining the strengths of UMIST and The Victoria University of Manchester Limiting factors of the current rTEDDI system

Combining the strengths of UMIST and The Victoria University of Manchester Current limitations 1. rTEDDI is currently limited to thin samples due to the low detection efficiency of Si at energies above ~20keV 2. Any pixelated detector used in the rTEDDI system must be able to handle high countrates ( ((hits/pixel)/second) for higher flux beamstations.

Combining the strengths of UMIST and The Victoria University of Manchester The ERD2004 detector P. Seller, W.J. Gannon, A.D. Holland, G. Iles, B.G. Lowe, M.L. Prydderch, S.L. Thomas, R. Wade, SPIE, EUV, X-ray and Gamma-ray Instrumentation for Astronomy IX, San Diego, CA, USA, (1998) July, vol

Combining the strengths of UMIST and The Victoria University of Manchester SCH04 MAC04 Pre-Amp Shaper Peak H. Comp. MAC04 SCH04 Crystal bump bonded to 16x16 array of pre- amplifier (MAC04). MAC04 wire bonded to two 1x128 arrays of shaping, peak hold and comparator circuits (SCH04). The ASIC is read out using a DAQ system consisting of a NI card controlled by software written in the LabVIEW environment Structure and reset schemes of the ERD2004

Combining the strengths of UMIST and The Victoria University of Manchester Measurements and Results

Combining the strengths of UMIST and The Victoria University of Manchester Np daughters Am-241 Cd&Te escape peaks In order to increase the energy range efficiency of the detector the 300µm Si crystal was substituted for a 2mm thick CZT crystal Flood Field irradiation setup Spectral response of EDR2004 using CZT to flood field irradiation irradiation by a Am-241 dial source Substituting Si for CZT

Combining the strengths of UMIST and The Victoria University of Manchester Countrate measurements Deadtime measurements (T reset measurement) Conclusions: DAQ system prevents the clocking frequency needed to obtain countrate requirements of rTEDDI Countrate limitations

Combining the strengths of UMIST and The Victoria University of Manchester CP CP-1 CP+1 CP+7 CP+8 CP+9 CP-9 CP-8 CP-7 Charge sharing correction tests Addition: Highest energy value pixel of the two is awarded the full charge and set as the central pixel for comparison with next event pixel. The lowest value pixel is set to zero. Discrimination: All charge shared events are set to zero. By targeting simultaneous hits on neighbouring pixels two charge sharing correction scripts where developed and compared

Combining the strengths of UMIST and The Victoria University of Manchester Charge sharing correction tests Conclusion: Charge sharing correction has poor result on this detector. Addition which is the ideal correction for rTEDDI since it does not throw away events is not valid due to the electronic cut-off

Combining the strengths of UMIST and The Victoria University of Manchester As a consequences of the ERD performance we have designed a specific ASIC for HEXITEC

Combining the strengths of UMIST and The Victoria University of Manchester HEXITEC Detector developed: Clocking frequency of 5Mhz Rolling shutter read-out (no electronic cut-off) Receiving prototype Sep. The HEXITEC detector and further work First experiments to run the rTEDDI system on thick samples using a high energy station in the beginning of next year MTPVT grown CZT available from Durham University at the end of the year.