Göttingen 2012 – scientific programme

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T: Fachverband Teilchenphysik

T 66: Halbleiterdetektoren: Strahlenhärte und neue Materialien

T 66.9: Talk

Thursday, March 1, 2012, 18:45–19:00, ZHG 001

Charge collection of scCVD diamond at cold to ultra-cold temperatures — •Hendrik Jansen¹, Heinz Pernegger¹, Vladimir Eremin², and Norbert Wermes³ — ¹CERN, Switzerland — ²IOFFE — ³University of Bonn

For the new series of triplet magnets, the Beam Instrumentation Group seeks a detector concept for a Beam Loss Monitor that provides full functionality at ultra-cold temperatures (1.9 K). A fast response time, excellent radiation hardness, long durability and reliability, good SNR, and a broad dynamic range are all critical properties. An obvious candidate for the detector material is single-crystal Chemical-Vapour-Deposited (scCVD) diamond.

A set-up for Transient Current Technique (TCT) measurements for CVD diamonds at ultra-cold temperatures has been put in place at CERN. Helium cooling allows for temperatures down to 1.9 K. Am-241 and Sr-90 sources provide ionizing radiation. Broad-band read-out electronics and a current-sensitive amplifier enable measurement of the transient current.

We will present results of measurements of the temperature dependence of fundamental diamond quantities such as carrier drift mobility and velocity, total charge yield, lifetime and detrapping time constants, and trapping energy levels. Furthermore, the difference between MIP-signals and α-signals is shown and important results for possible detector operations are derived. A model capable of explaining parts of the data - the plasma effect with associated recombination, trapping and detraping - will be presented for scCVD diamonds.