Radiation Sensors at High Temperature using Diamond Detectors

Transcription

1 Radiation Sensors at High Temperature using Diamond Detectors Peter R Hobson Particle Physics Group Department of Electronic & Computer Engineering, Uxbridge, UB8 3PH UK Single crystal diamond sensor at Brunel University London.

2 Motivation In the context of this talk High temperature is above about 170 C Two key application areas motivate the work discussed in this talk 1) Radiation monitoring near high temperature regions of nuclear power plant 2) Deep oil and gas well logging uhpht* definition in the UK has T > 166 C Key challenges are potentially different in these two applications 1) Long life (> ten years), high total dose, high temperature 2) Short life (< few thousand hours), moderate dose, high temperature + pressure + vibration [1] * Ultra High Pressure High Temperature (see DECC (2010) OT21410) [1] Proc IEEE Nucl. Sci. Symp. Conf. Rec. (NSS/MIC), 2010, pp

3 Outline of talk Diamond as a radiation sensor Recent results on diamond radiation sensors at high temperatures Recent results on other wide band-gap materials Prospects and challenges for the future 3

4 Diamond A wide band-gap material (E g = 5.5 ev). Electron and hole mobilities of about 4500 cm 2 V 1 s 1 and 3800 cm 2 V 1 s 1, respectively, in intrinsic, single-crystal CVD diamond at 293 K [2]. Can be doped p-type (B with 0.37 ev activation energy) or n-type (N with 1.7 ev activation energy). Rob Lavinsky, irocks.com CC-BY-SA-3.0 [CC BY-SA 3.0 ( via Wikimedia Commons Available in natural (type II relevant here), polycrystalline (pcvd) and mono-crystalline CVD. Different grades are commercially available heatsink, optical, electronic. [2] Isberg, J., et al., Science (2002) 297, 1670 By Kugel (Own work) [CC BY-SA 3.0 ( or GFDL ( via Wikimedia Commons 4

5 Diamond A great deal of research, motivated particularly by the challenges posed by the environment of the Large Hadron Collider at CERN, have demonstrated the generally excellent radiation tolerance of recent CVD diamond (e.g. RD42 collaboration [3]) Recent results from RD42 [4] indicate: Charge Collection Distance: routinely > 300 µm Average signal pulse height of pcvd diamond detectors irradiated up to the dose of neutrons cm -2 does not depend on the particle flux up to 10 MHz.cm -2 The successful operation of the first pcvd diamond planar pixel device in an LHC experiment [ATLAS Diamond Beam Monitor] [3] W. Adam, et al. [RD42 Collaboration]. Development of Diamond Tracking Detectors for High Luminosity Experiments at the LHC. Proposal/RD42 CERN/DRDC 94-21, Status Report/RD42, CERN/LHCC, 95-43, 95-53, 95-58, 97-03, 98-20, , , , , , , , , [4] Alexopoulos A. et al PoS Vertex 2016 (2017) 027 5

6 Recent results on diamond radiation sensors at high temperatures Some published (and some preliminary) results from Brunel University London. Some published results from the University of Surrey. Some published results from other groups. 6

7 This work was funded by EPSRC and was in collaboration with Micron Semiconductor Ltd (UK) via a linked TSB project [5] Our results shown here use single-crystal electronic grade CVD diamonds ( mm) sourced from Element Six. We worked with Schlumberger (92140 Clamart, France) to provide the down-hole oil well logging expertise. 2.0 mm C total = 3.1 pf C diamond = 0.5 pf R total > 200 GΩ 4004 Preamp 2021 Spectroscopy amp (4 s) 2048 channel MCA Readout electronics (Canberra) at room temperature Sensor exposed to alpha sources ( 241 Am, 244 Cm, 239 Pu) inside a vacuum chamber at < 10-5 mbar [5] High Temperature Radiation Hard Detectors (HTRaD): Grant EP/L504671/1 and TSB Project #

8 High temperature results - Brunel Conductive epoxy: Duralco 120 from Cotronics Corp. PCB: 1mm thick Rubalit 708S from CeramTec GmbH. Cable: 50Ω coaxial rated at 250 C Heating of the sensors was accomplished using a copper block with an attached AlN heater element and Pt-100 thermometer within the chamber. This was attached by multi-way vacuum feedthrough to an external temperature controller (Lakeshore 331). Electronic readout of the system was carried out by connecting internally with coaxial cable to vacuum feed-through connectors. 8

9 Brunel results ~ 20 C Simulations shown used FLUKA 2011 [6]. Graphs are as shown in reference [7]. [6] FLUKA: a multi-particle transport code A. Ferrari, P.R. Sala, A. Fasso`, and J. Ranft, CERN (2005), INFN/TC_05/11, SLAC-R-773 [7] A. Metcalfe et al 2017 JINST 12 C

10 Brunel results ~ 20 C to 250 C V bias V bias Preliminary analysis: Four nominally identical sensors gave CCE ~ 99% up to T = 200 C Alpha peak energy resolution better than 1% up to 200 C 10

11 Other studies on diamond at elevated temperatures mm 2 Ag contacts 4 4 mm 2 Pt contacts Energy in kev 241 Am source [8] [8] Hodgson M et al, Meas. Sci. Technol. 28 (2017) [9] Pilotti R et al, JINST (2016) C mm 2 Pt contacts, +200 V bias [9] 11

12 Other studies on diamond at elevated temperatures A number of other recent studies have also shown the potential of diamonds to operate as radiation detectors at elevated temperatures. For example: Masakatsu Tsubota et al [10] reported operation of a reconditioned DDL diamond with Ru Schottky and TiC/Pt ohmic contacts up to a temperature of 250 C. At lower temperatures (200 C) a CCE of 96.9 % and an alpha particle energy resolution of 3% at 5.5 MeV was demonstrated. Amit Kumar et al [11], using 5 5 mm 2 diamonds from IIa Technologies Pte, demonstrated that with Cr/Au contacts an alpha particle energy resolution of 2% at 5.5 MeV was obtained at 300 C [10] Masakatsu Tsubota et al, NIM A 789 (2015) 50 [11] Amit Kumar et al, NIM A 858 (2017) 12 12

13 SiC radiation sensors SiC is a wide band-gap semiconductor (E g = 3.23 ev for 4H-SiC) Many applications for high power electronics (Schottky diode, JFET, MOSFET) and commercial products available from ST, Infineon, Cree etc. I will discuss data from work at University of Surrey [12, 8] [12] Ambubakar Y M et al, IEEE Trans Nuc Sci 62 (2015) 2360 Reverse bias leakage current of 4H-SiC Schottky diode 13

14 SiC radiation sensors Stability with time for peak and FWHM of 241 Am signal at 100 V bias [12] 14

15 SiC radiation sensors 241 Am source temperature effect on count rate for two different SiC sensors [8] 15

16 Prospects and challenges for the future The positive message is that diamond (and probably SiC) have been demonstrated to be radiation sensors which will operate at temperatures in excess of 200 C. Work relating to CERN LHC experiments confirm the excellent quality and radiation tolerance of commercially available CVD diamond. Most published work has concentrated on measuring high energy alpha particles as many applications are aimed at neutron detection direct with 12 C or via 10 B or 6 Li converters depending on the neutron energy range. Stability of response has been shown over moderate (~1 day) time periods. However we are still trying to understand polarisation effects, the different responses with different contact metals, different surface preparation techniques, the use of epi layers (or not) on SiC and indeed self-bias (or not). 16

17 Prospects and challenges for the future High temperature packaging, and the ability to operate for long periods (years) and for some applications the need to survive very high shock is still to be demonstrated. However the really big issue is the challenge to make low noise front-end electronic amplifiers which will also operate at these elevated temperatures! Passive components and a few operational amplifiers are now commercially available (though op-amp life limited to ~ 2000 hours at 200 C), but the development of a low-noise JFET or bi-polar high temperature pre-amp is an essential next stage. Some UK-based work at Sheffield University and University of Sussex, for example, on semiconductor materials such as InGaP, AlGaAs etc. is promising. I am sure that developers of 3D diamond sensors (in the UK Manchester & Oxford) will be soon testing them at elevated temperatures. 17

18 Acknowledgements Many thanks to my Brunel, Micron Semiconductor and Schlumberger (Clamart) collaborators.* Thanks also to Annika Lohstroh (University of Surrey), Michael Hodgson (BECQ) and Ricardo Pilotti (ITER) for permission to use their published figures. diamond studies received support from EPSRC under grant EP/L504671/1 Diamond sensors arising from the Brunel University/Micron Semiconductor collaboration are commercially available from: Micron Semiconductor Ltd., Lancing, BN15 8SJ UK * Alex Metcalfe, George R. Fern, Terry Ireland, Ali Salimian, Jack Silver, David R. Smith Gwenaelle Lefeuvre and Richard Saenger 18