Development of Single Crystal Chemical Vapor Deposition Diamonds for Detector Applications

Transcription

1 Development of Single Crystal Chemical Vapor Deposition Diamonds for Detector Applications Contacts Project Summary H. Kagan, K.K. Gan, R. Kass Department of Physics, The Ohio State University R. Wallny Department of Physics and Astronomy, UCLA Progress in experimental particle physics depends crucially upon the ability to carry out experiments in high radiation areas. Existing tracking devices and monitoring systems are presently based on the mature silicon technology which functions very well in relatively low radiation environments but may fall short of what is required for future experiments. Hence new radiation hard technologies must be developed to fill this gap. Diamond is one such technology. With the commissioning of the LHC expected in 2009, and the LHC upgrades expected in 2013, all LHC experiments are planning for detector upgrades which require radiation hard technologies. Chemical Vapor Deposition (CVD) diamond has now been used extensively in beam conditions monitors as the innermost detectors in the highest radiation areas of BaBar, Belle and CDF and is planned for all LHC experiments. As a result, this material is now being discussed as an alternative sensor material for tracking very close to the interaction region of the super-lhc where the most extreme radiation conditions will exist. This proposal addresses the further development of the new material, single-crystal Chemical Vapor Deposition diamond, towards reliable industrial production of large pieces and new geometries needed for detector applications. The important points of the proposal are: Polycrystalline CVD (pcvd) diamond material has been demonstrated to be grown reliably by industry and has been measured to be more radiation hard than silicon. Several of the authors of this proposal pioneered the research and development of CVD diamond detectors and are world leaders in this technology. Polycrystalline CVD material inherently has grain boundaries and defects which limit the collected charge. Single-crystal CVD (sccvd) diamond has been grown (in small sizes) and solves many if not all of the issues associated with pcvd material. With the resources requested in this proposal, the following will be accomplished. Work with the two companies most advanced to develop a reliable method to grow larger area sccvd diamond. Develop and transfer the metalization techniques required for proper radiation hard operation of this material to industrial partners. Explore new geometries in sccvd diamond such as 3D structures.

2 Project Narrative Groups Requesting Direct Funding Applicants: Address: Harris Kagan, K.K. Gan, Richard Kass Dept. of Physics, The Ohio State University 191 West Woodruff Avenue, Columbus, OH Work Phone: kagan@mps.ohio-state.edu Applicant: Rainer Wallny Address: UCLA Dept. of Physics and Astronomy 475 Portola Plaza, Los Angeles, CA, Work Phone: wallny@physics.ucla.edu Funding Opportunity Announcement Number: DE-PS02-08ER08-31 DOE Program Office: Office of High Energy Physics Technical Contact: Dr. Howard Nicholson Contacts 1 Introduction Detectors and radiation monitors of future experiments will be situated in radiation environments several orders of magnitude harsher than those of any current detector [1]. At present detectors for tracking close to the interaction region are based on the mature silicon technology which functions very well in relatively low radiation environments. However, the practical limits on the radiation hardness of silicon still falls short of what is required for many future experiments. Hence new radiation hard technologies must be developed to fill this gap. Diamond is one such technology. In Table 1, we summarize the properties of diamond and, for comparison, those of silicon that are of interest when considering the material for use as a detector. The most distinctive feature of diamond is its large band gap, 5.5 ev. This large band gap along with the associated large cohesive energy are responsible for much of the radiation hardness of diamond. The large band gap also makes diamond an excellent electrical insulator. As a result, a large electric field can be applied without producing significant leakage current. Thus, there is no need for a reverse biased pn-junction and the diamond detector functions much like a solid-state ionization chamber. Diamond has two additional properties that compare favorably to silicon. Its smaller dielectric constant yields, for a given geometry, a lower detector capacitance and thereby, lower noise performance of the associated front-end electronics. In addition, even though diamond is 1

3 an electrical insulator, it is an excellent thermal conductor with a thermal conductivity exceeding that of copper by a factor of five at room temperature. This is important since a common problem with large detector systems is the management of the thermal load generated by the large number of electronic channels used in the detector readout. The handling of this thermal load would be simplified if the detectors were constructed from diamond since the diamond would act as a heat spreader. Although diamond appears ideal in many respects it does have a limitation: the large band gap which produces many of its outstanding properties also means that its signal size is at most half that of silicon for a given detector thickness in radiation lengths. This is somewhat compensated by lower front-end electronic noise due to diamond s nearly non-existent leakage current and diamond s lower capacitive load. Property Diamond Si Band Gap [ev] Breakdown field [V/cm] Resistivity [Ω-cm] > Intrinsic Carrier Density [cm 3 ] < Electron Mobility [cm 2 V 1 s 1 ] Hole Mobility [cm 2 V 1 s 1 ] Saturation Velocity [km/s] Mass Density [g cm 3 ] Atomic Charge 6 14 Dielectric Constant Thermal Expansion Coefficient [K 1 ] Thermal Conductivity [W m 1 K 1 ] Cohesive Energy [ev/atom] Energy to create e-h pair [ev] Radiation Length [cm] Spec. Ionization Loss [MeV/cm] Ave. Signal Created/100 µm [e] Ave. Signal Created/0.1% X 0 [e] Table 1: The physical properties of diamond and silicon at 293K [2]. 1.1 CVD Diamond The discovery of the growth of diamond using the Chemical Vapor Deposition (CVD) process allowed the consideration of large scale use of diamond detectors. In this process, a hydrocarbon gas, such as methane, is mixed with a large concentration of molecular hydrogen gas. The gas mixture is then excited by an energy source. The resulting reactive gas mixture is brought into contact with a substrate where carbon based radicals are reduced and the carbon atoms link together with single bonds (sp 3 hybridized orbitals) forming a diamond lattice. Raman spectroscopy and X-ray diffraction unambiguously show that the CVD films are diamond where the detailed structure (polycrystalline or single-crystal) depends on the substrate employed during growth. For the last ten years the RD42 Collaboration at CERN has worked to develop detectors based on polycrystalline CVD (pcvd) diamond [3]. They have succeeded in constructing detectors with feature sizes from µm to cm. They have measured the radiation 2

4 hardness up to fluences greater than hadrons per cm 2 and have found it to be sufficient to allow diamond detectors to operate for several years at the highest design luminosity of the LHC. Moreover, RD42 found that diamond detectors show no evidence of any damage from electrons and photons up to 1000 MRad. 1.2 Principles of Diamond Detectors In Fig. 1, we show the basic principle of using diamond as a particle detector. A voltage is applied across a layer of diamond a few hundred microns thick. When a charged particle traverses the diamond, atoms in crystal lattice sites are ionized, promoting electrons into the conduction band and leaving holes in the valence band. On average, 3,600 electron-hole pairs are created per 100 µm of diamond traversed by a minimum ionizing particle. These charges drift across the diamond in response to the applied electric field producing a signal that can be measured. Since there may be traps in pcvd material we use the term collection distance to denote the average distance the electron-hole pair drift apart. Over the last few years, the RD42 Collaboration has worked closely with Element Six Ltd. [4] and their spinoff Diamond Detector Ltd. [4] to achieve improvements in the charge collection and uniformity of pcvd diamond. This work has now resulted in large scale wafers of high quality diamond. In Fig. 2 we show recent polycrystalline CVD wafers ready for test with contacts placed at one centimeter intervals. A summary of the present status of pcvd diamond is listed below: Figure 1: A schematic view of a diamond detector. pcvd diamond from production reactors now regularly exceeds 250 µm charge collection distance in wafers with 12cm diameter. Research pursued by RD42 in conjunction with Element Six yielded pcvd diamonds with 300 µm collection distance. The radiation hardness of high quality pcvd diamond was tested up to p/cm 2. Pixel devices useful at the LHC for ATLAS were constructed including a full diamond AT- LAS pixel module utilizing the same FE-I3 electronics (IBM) and bump-bonding (IZM Berlin). This module achieved lower noise and threshold spread and comparable efficiency as a silicon module. pcvd diamond based beam condition monitors are now in use or planned for BaBar, CDF, ATLAS and CMS. The grains in pcvd material limit the spatial resolution, uniformity, and collected charge. 3

5 Figure 2: As-grown pcvd wafers ready for test with contacts at one centimeter intervals. 2 Single-Crystal CVD Diamond In last five years the first single-crystal diamonds grown by a chemical vapor deposition process [5] became available. The samples were synthesized with a microwave plasma-assisted CVD reactor using a specially prepared h100i oriented single-crystal synthetic diamond substrate. These diamonds were typically cm2 in area and 400 µm thick. This group using 2006 ADR funds [6], together with RD42 developed and tested this material. As a direct result of this work the thickness, size and quality of the sccvd diamonds having been increased. Member of our group have manufactured in this material strip detectors and pixel detectors, characterized them in test beams and measured the radiation hardness of this new material. To date, members of our group (in the previous ADR) have obtained the following results: The pulse height distribution for sccvd diamond is very narrow, Up to a diamond thickness of 770 µm full charge collection is observed, The largest area high quality diamond produced was just over 0.64 cm2, Strip and pixel detectors show charge collection and charge sharing as expected, Up to low fluences, sccvd and pcvd have the same damage constant. These results are discussed below. In Fig. 3 (a) we show the pulse height spectrum observed from a 450 µm thick single-crystal CVD diamond. We observe a collection distance consistent with full charge collection; most probable charge of 13,400e; FWHM of 4000e; and more than 10,000e separation between the pedestal and the beginning of the charge distribution. The FWHM/MP for these single-crystal CVD diamonds is approximately 0.3, about one third that of polycrystalline CVD diamond and about two thirds that of correspondingly thick silicon. In Fig. 3 (b) we show the most probable charge for sccvd diamond versus thickness of the material. A clear linear relationship is evident out to thicknesses of 770 µm. In Fig. 4 we show a photograph of the most recent sccvd diamonds which are approximately 1cm2 in size. These diamonds were characterized and made into strip and pixel detectors [7]. 4

6 (a) (b) Figure 3: (a) The pulse height distribution from a 450 µm thick sccvd diamond. The red and blue curves are the data for positive and negative bias applied to the diamond. (b) The most probable pulse height versus thickness for sccvd diamonds. Figure 4: Picture of the latest sccvd diamonds which our group tested. 3 Radiation Hardness Studies with CVD Diamond In order to obtain the most reliable irradiation results, together with RD42, our irradiation program consists of testing each sample prepared as a strip detector in a CERN test beam before and after irradiation of the samples. During the last three years we performed three irradiations of diamond samples and correspondingly three test beams. Fig. 5 shows a photograph of four sccvd samples prepared as strip detectors and read-out with VA-2 electronics for characterization in the test-beam at CERN. Both pcvd and sccvd samples were prepared in this manner. Fig. 6 shows the results of the pulse height spectrum for a recent pcvd diamond after p/cm2. A clear Landau distribution is observed in the data with the mean observed charge of 7300e and a most probable charge of 6000e. To set the scale, for use at the LHC as a pixel detector with ATLAS FE-I3 electronics it is estimated that a minimum charge of 2200e (1400e threshold plus 800e overdrive) corresponds to an efficiency of > 99%. Fig. 7 shows the results of the pulse height spectrum for a recent sccvd diamond before and after p/cm2. Clear Landau distributions are observed in the data with the mean ADC counts of 1393 before irradiation and 837 after irradiation. This data has been added to the previous irradiation data to summarize the proton irradiation results. In order to estimate the radiation effects on the collection distance we have compared the collection distances for pcvd and sccvd samples 5

7 before and after irradiation. The sccvd diamond is expected to be representative of the next generation high quality polycrystalline material. By comparing the effective damage constants for the two different materials we can definitively find the relation between the two. In Fig. 8 we overlay the collection distance measurements of pcvd and sccvd samples before and after irradiation so that 0 on the x-axis corresponds to the un-irradiated collection distance of our pcvd material. In addition the sccvd fluences are shifted by p/cm 2. In effect the sccvd material starts with a signal advantage that corresponds to a fluence of about p/cm 2. Another way of thinking of this is that our un-irradiated pcvd material has that same number of trapping centers as the sccvd material after a dose of p/cm 2. Figure 5: Photographs of the four 0.5cm 0.5cm sccvd samples characterized in the 120 GeV pion beam at CERN in Fall 2007 and Fall Figure 6: The pulse height spectrum from an irradiated pcvd strip detector after p/cm 2. A clear Landau distribution of pulse heights is observed. Fig. 8 shows that all of the irradiations fall along a single damage curve given by the equation 1/ccd = 1/ccd0 + kφ where ccd0 is the initial collection distance and k, the damage constant is independent of the initial collection distance. This result now includes sccvd samples that have initial collection distances in excess of 400 microns. We do not expect the higher quality pcvd 6

8 Figure 7: The pulse height spectrum from an irradiated sccvd strip detector before and after p/cm 2. Clear Landau distributions are observed. material to be any different. The data indicate a single damage constant k for both materials indicating that the next generation of material should follow a similar curve. Figure 8: Summary of proton irradiation results for pcvd (blue points) and sccvd (red points) material at an electric field of 1 V/µm and 2 V/µm (solid green square point) to a fluence of p/cm 2. The black curve is a standard damage curve 1/ccd = 1/ccd0 + kφ. The sccvd data has been shifted to the left by a fluence of p/cm 2 where its un-irradiated collection distance falls on the curve. With this shift the pcvd and sccvd data fall on a single curve indicating the damage due to irradiation is common to both. 4 Applications of CVD Diamond The first large scale application of diamond in high energy physics was radiation monitoring. Radiation monitoring plays a crucial role in any experiment which operates a high precision tracking system close to the interaction region. Experience has shown that to protect the inner 7

9 tracking devices systems must be provided that can be mounted close to the inner tracking devices they are designed to protect and that can abort the beams on large current spikes. In addition, radiation monitoring allows for the measurement of the daily dose and integrated dose which the tracking systems receive and thus allow the prediction of device lifetimes, etc. 4.1 BaBar Beam Condition Monitors In 2002 the BaBar experiment [8] installed two pcvd to gain experience with the operation of diamond sensors as beam condition monitors since the then installed silicon PIN-diodes were failing [9, 10]. The diamonds (1 cm 2 ) were placed in the horizontal plane, 15 cm from the interaction region, 5 cm away from the PIN-diodes. The diamonds were read out using a PIN-diode readout board. Both diamonds were under high voltage and readout for more than 4 years until the demise of BaBar. They are estimated to have received over 2 MRad of radiation each since they were installed and both performed reliably with leakage currents well below 0.1 na and with beam induced currents proportional to the dose rate. During this time the two PINdiodes closest to the diamonds have become radiation damaged and so BaBar relied on the diamonds to provide dose measurements. In Fig. 9 we show the LER machine current (upper trace), the BE diamond current (middle trace) and the BE:MID silicon PIN-diode current (lower trace) during the initial operation of the BaBar experiment. During the 8 hours displayed, a clear fast abort and slow abort occurred in both the silicon and the diamond. Note that the signal responses of each are similar. After exposure to over 2 MRad the diamonds did not show any degradation of signal. The signal currents from both diamonds provided prompt feedback to the BaBar shifters and the machine operators. Figure 9: A comparison of a pcvd diamond sensor and a silicon PIN-diode monitoring radiation in the BaBar silicon detector during the initial installation. During this data taking the beam current (upper trace) gradually decreases between successive fills of the storage ring. The diamond sensor current (middle trace) is comparable to that of the silicon PIN-diode (lower trace). At two points the beam is aborted. The first abort is due to an acute spike in the dose rates; the second abort is due to a smaller but longer lived increase in the dose rates. Both aborts are seen in both sensors. 8

10 4.2 CDF Beam Condition Monitors Since the Tevatron fall shutdown in 2004, CDF has been operating pcvd diamonds provided by RD42. The initial prototype, deployed in 2004 close to the CDF silicon detector, was read out with a Keithley 6517A electrometer. The data accumulated with this prototype encouraged the design of a pcvd diamond beam condition monitoring system to overcome limitations of the existing CDF beam abort system based on argon ionization chambers as used by the beam loss monitoring (BLM) system. The final system, commissioned in spring 2006, consists of 13 diamonds. Two groups of four diamonds were deployed in the inner tracking volume at z = 1.7 m away from the interaction point at a radius of about 2 cm, and five more in the detector stations of the BLM system outside of the detector at z = 4.3 m at a radius of 20 cm to allow for cross calibration of the new diamond and the legacy beam abort system. The sensors are readout over a 85 m long triaxial cable and connected to current amplifying electronics developed for the Tevatron BLM upgrade [11] located in the CDF electronics floor outside of the collision hall. Fig. 10 indicates the Figure 10: Diamonds localization within the CDF detector. The (eight) blue dots indicate the localization of the diamonds inside the tracking volume, the red dots indicate diamonds outside the tracking volume. locations of the diamond sensors within the CDF detector. A more detailed description of the system can be found in [12]. Figure 11: Current of diamonds during beam injection at the Tevatron versus time. The current of one of the diamonds inside the tracking volume is shown in red. The current of one of the BLM station diamonds is shown in blue. Fig. 11 shows the response of one tracking station diamond and a diamond located near a 9

11 BLM chamber during the sequence of accelerator events leading to proton-antiproton collisions, or shot-setup. The inner tracking diamond shows more distinct features than the diamond at larger radii, underlining the clear advantage (at least for the CDF detector) to mount diamond detectors as close as possible to the beamline. The system has been running stably since commissioning in 2006, and it is estimated that the inner tracking diamonds have been exposed to a radiation dose of up to 5 MRad [13]. Figure 12: CDF BCM Diamond currents (blue) versus time for buffer dump obtained on Nov. 10th, 2008 at 4:48pm. The red line shows the status of the beam permit which is dropped as more than 3 diamonds registered currents above the abort threshold of 9000 mrad/sec. The drop of the beam permit triggered the abort of the Tevatron beams. After a series of internal reviews, the CDF diamond beam condition monitoring system became the default beam abort system of CDF as of September Until the LHC experiments will switch on, it is thus the largest diamond beam abort system of its kind operating at a hadron collider. The CDF diamond beam abort system has already triggered its first beam abort on Nov. 10th, The cause of the abort is suspected to be a electrostatic separator spark in the B11 sector of the Tevatron, and our abort decision was confirmed by the F4 and D1 quench protection systems. At the time of the abort, the CDF muon chamber high voltage tripped as well, due to high particle rates, indicating a real malfunction of the Tevatron accelerator. Fig. 12 shows the buffer memory histories of 4 diamonds during this first abort triggered by the CDF diamond beam abort system. No signals were recorded in the legacy BLM beam abort system. 4.3 ATLAS Beam Condition Monitors ATLAS has a similar application to BaBar and CDF. The ATLAS experiment decided in 2005 to pursue a proposal to build a BCM detector based on pcvd diamond sensors. The aim is to detect minimum ionizing particles with good signal over noise ratio and a time resolution of 1 ns. The choice of diamond sensors was motivated by the radiation hardness of diamonds, the high charge carrier velocity leading to very fast and short current signal, very narrow pulses due to short charge carrier lifetime and very low leakage currents even after extreme irradiations. No detector cooling is needed. The ATLAS BCM is already installed [14]. For a backup system ATLAS decided to build a second Beam Loss Monitor (BLM) system. This system was constructed during the last year and has already been installed as well. In Fig. 13 we show a schematic view of the ATLAS BCM plan where the diamond monitors are placed in modules on the forward disks of the pixel detector. A module consists of a box housing two pcvd diamonds of 1cm 1cm area with square contacts 8mm 8mm mounted back to back. The signals from two sensors are fed in parallel into one channel of very high bandwidth current amplifiers. The design aim of a module is a S/N ratio of 10:1 in order to detect minimum ionizing particles with high efficiency. 10

12 The ATLAS system consisting of 10 modules including spares is complete and installed. Fig. 13 shows a finished module. In Fig. 14 we show the test beam results for the time difference of two final modules with a measured rms of 0.7ns. (a) (b) Figure 13: (a) A schematic view of the ATLAS BCM system. (b) A photograph of the final module used by ATLAS for its BCM system. Figure 14: The timing difference distribution of two final ATLAS BCM modules. In Fig. 15 we show the test beam results for the efficiency and noise occupancy scaled to a 25ns interval of a final module. At 99.5% efficiency the noise rate is 10 6 ; at 97.5% efficiency the noise rate is The final modules meet all of the initial specifications. In Fig. 16 we show one half of the installed final BCM system. 11

13 (a) (b) Figure 15: The efficiency (a) and noise-rate (b) as a function of threshold of a final ATLAS BCM module measured in a CERN test beam. Figure 16: Photo of one half of the final ATLAS BCM system installed on the beam pipe. 4.4 CMS Beam Condition Monitors The CMS collaboration has chosen pcvd diamond for their baseline beam condition monitoring system. The CMS system consists of two stations at different distances along the beam from the interaction point. The BCM1 station is adjacent to the forward pixel detectors about 1.8 m away from the interaction point at a radius of 4.5 cm, close to the beam pipe. BCM1 will thus be dominated by radiation originating mostly from proton-proton interactions. The BCM2 station is located outside of the CMS detector about 14.5 m away from the interaction point at a radius of about 29 cm. BCM2, being shielded from the interaction point, will be mostly sensitive to the beam halo, and provide thus a complementary beam condition measurement to BCM1. The BCM1 station supports two types of sensors. The baseline system, BCM1L, consists of DC coupled pcvd diamonds and provides current signals in the same way as the CDF or BaBar system. The readout time granularity of this system is 5 µs. A second branch, BCM1F, employs single-crystal sensors, with radiation tolerant amplification electronics close to the sensor and signal transmission using the analog opto-hybrid of the CMS pixel detector system [15]. The 12

14 (a) (b) Figure 17: (a) A diamond detector used in the CMS BCM system. (b) First pulses in BCM1F observed with an oscilloscope during September 10th, readout time granularity of this system is 25 ns. The BCM1F system has already detected signals during the commissioning of the LHC beams at injection energy on September 10th, 2008 (see Figure 17 (b)). 5 The Proposed Program Due in large part to the pioneering work of many members of this collaboration and the continued leadership in diamond development, CVD diamond detector technology has developed from a mere concept to the point of being poised to play a major role in particle physics experiments. We propose a program to develop and test single-crystal CVD diamond. Each application listed above would have a larger signal to noise and work better with single-crystal CVD diamond. Moreover, our collaboration possesses the unique experience with diamonds in both lepton and hadron colliders necessary to carry this program forward to the next stage with single-crystal CVD diamond. If diamond detectors are to move into the high radiation areas of future experiments it is compelling to develop this technology soon. We propose a program to exploit the properties of sccvd diamond. Part one of the program is to work with the two companies most advanced (one in the UK and one in the US) to develop a reliable method to grow large pieces of sccvd diamond. Ohio State University will lead this portion of the program. This will take a number of development runs. Part two of the program is to work with a number of detector companies to develop and transfer the metalization required for proper radiation hard operation of this material. Ohio State University who already has experience with transferring technology to IZM in Berlin will lead this part of the program. Part three of the program is to explore new geometries in sccvd diamond (e.g. 3D structures) to extend the radiation hardness of the material for future applications. Both Ohio State University and UCLA will participate in this part of the program. Part four of the program is to test and evaluate our results. This requires the construction of various devices on hybrids together with 13

15 electronics to be tested in source and beam tests before and after irradiation. UCLA will lead this portion of the program. 5.1 sccvd Diamond Fabrication and Testing The central point of our proposal is to build on our previous work to improve sccvd diamond. This must be performed in collaboration with our RD42 colleagues and Element Six/Diamond Detector Ltd. We will also engage a company in the USA to develop their production capability. As explained above, this is quite natural and has been a highly productive effort over the past years. In the next two years, we expect to concentrate on the following tasks: Scaling of the size of sccvd diamond. Size is the key issue for sccvd diamond. We believe that we must attain 2 cm 2 sizes at a minimum for use in radiation monitoring, pixel detectors, and trackers. Although a small number of parts have been produced at 1 cm 2, their production is by no means routine and their quality to the edges is not assured. Once we attain 1 cm 2 area with the present methods we will work with industry on new methods to grow larger sccvd diamonds. Our role here will be to provide feedback to industry on their growth runs. Device Production and Measurement. The signal size of sccvd diamond is a critical issue. OSU and UCLA will have the equipment to characterize sccvd diamonds. In addition to serving as a feedback loop to the diamond producers, the proposed work should also advance the understanding of diamond. At OSU we have the demonstrated capability to produce devices ranging from single large pad detectors to small pixel detectors for rapid testing. 5.2 Development of Industrial Device Production One of the key lessons learned in the construction of pixel detectors is that the more can be accomplished in industry, the better the overall performance of the devices. Concurrent with Part one above we plan to work with IZM in Berlin on the development of an industrialized metalization and bump bonding process. The goal here is to send a clean diamond to a company and have a fully working radiation hard device return. Radiation Hardness. One of the primary goals of the coming year is to establish the radiation hardness of sccvd material metalized and bump bonded in industry. Irradiations have been performed successfully in the past by members of this ADR proposal and RD42 at the CERN PS irradiation facility ([16]). The irradiations are performed by CERN free of charge and superior dosimetry based on Al foil activation and NaI and Ge spectrometry is available. With these facilities, fluence measurement uncertainties can be confined to ±6%. 14

16 5.3 Exploration of New Radiation Hard Geometries Our measurements indicate that although diamond is more radiation hard than silicon, it also suffers from damage. In particular the collection distance falls with fluence. One natural way to collect all the charge is to place electrodes closer than the collection distance. This means electrode spacing of the order of 50µm to create a device which would collect essentially all the deposited charge up to a fluence of p/cm 2. This would be quite an achievement and would set diamond apart from all other competitors. Although there are many ways to accomplish this goal one method involves placing electrode transverse to the faces of the diamond in the bulk in a 3D geometry. A 3D-diamond detector would include all the benefits of diamond and 3D technologies and potentially be the most radiation hard detector with the lowest power dissipation ever made. Moreover the detector would not have to be cooled. Creating such a device relies on etching technologies normally associated with micro-machining. In the case of diamond holes can be etched by using metal absorption at high temperatures and vacuum. We have contacted two companies who specialize in this technique and they are interested in trying to make such a device. Two alternate methods of accomplishing the same task are to grow the diamond with the contacts embedded into it or to implant electrodes deep into the bulk. These may also be possible and we plan to see if we can get industrial partners to pursue either of these methods. The responsibility for this part of the program will be shared between OSU and UCLA. The two year program to develop new radiation hard structures is: Electrode etching of test structures and characterization of the resulting structures. Characterization of the test structures before and after irradiation. Fabrication of tracking devices to measure the charge collected, charge sharing and efficiency. 5.4 Testing and Evaluation for Results The last part of our program is to test and evaluate our results. Test beam data will be accumulated and analyzed by the UCLA group. This also requires the construction various devices on hybrids together with electronics to be tested in source and beam tests before and after irradiation. UCLA will lead this portion of the program. 15

17 5.5 Responsibilities Note: 1=lead responsibility 2=secondary responsibility OSU UCLA sccvd Diamond Development Scaling of physics size 1 2 Measurement of signal size 1 2 sccvd characterization 1 2 Industrial Device Development Contact deposition 1 Device characterization studies 1 2 Materials characterization studies 1 2 Radiation Hardness Studies Device design 1 1 Fabrication of devices 1 Device Testing 2 1 Radiation hardness studies 1 1 Comparison studies (pcvd, Si) 1 Optimization of electronics 1 2 Exploration of New Geometries 3D Device design 1 2 Implantation design 2 1 Characterization of test structures 1 1 Testing and Evaluation of Devices Beam tests 2 1 Irradiations 2 1 Analysis of data

18 5.6 Milestones Year 1 Acquire and characterize 1cm 1cm diamond pieces Characterize a number of sccvd diamonds Irradiate a number of sccvd diamonds Provide feedback to companies Construct and test radiation hard devices Year 2 Confirm radiation hardness of sccvd diamond in beam tests Investigate alternate structures Compare the radiation hardness of alternate structures 17

19 References [1] 1st Workshop on Radiation Hard Semiconductor Devices for Very High Luminosity Colliders, CERN, Nov [2] S. Zhao, Characterization of the Electrical Properties of Polycrystalline Diamond Films, Ph.D. Dissertation, Ohio State University (1994). [3] W. Adam et al. (RD42 Collaboration), Development of Diamond Tracking Detectors for High Luminosity Experiments at the LHC. Status Report/RD42, CERN/LHCC 97-3, 98-20, , , , , , , , , [4] Element Six Ltd., King s Ride Park, Ascot, Berkshire SL5 9BP UK; Diamond Detector Ltd., 16 Fleetsbridge Business Centre, Upton Road, Poole, Dorset BH17 7AF UK. [5] J. Isberg, et al., High Carrier Mobility in Single-Crystal Plasma-Deposited Diamond, Science 297 (Sep. 2002) [6] R. Wallny, H.Kagan, K.K. Gan, R. Kass and W. Trischuk (ADR 2005), Fabrication and Testing of Single Crystal Chemical Vapor Deposition Diamonds for Detector Applications, UCLA, OSU, U Toronto, DOE ADR Proposal (2005). [7] R. Wallny et al., Status of diamond detectors and their application, Nucl. Instr. and Meth. A582 (2007) 824. [8] B. Aubert, et al. (BaBar Collaboration), The BaBar Detector, Nucl. Instr. and Meth. A479 (2002) 1. [9] B. Petersen, et al., Radiation Hardness and Monitoring of the BaBar Vertex Tracker, Nucl. Instr. and Meth. A518 (2004) 290. [10] A. Edwards, et al., Radiation Monitoring with Diamond Sensors in BaBar, IEEE Trans. Nucl. Sci. 51 (2004) [11] Al. Baumbaugh, BLM Upgrade User s Guide,BEAMS-DOCS %20Guide.pdf [12] P. Dong et al., A Beam Condition Monitoring System for the CDF Experiment,, IEEE Trans. Nucl. Sci. 55 (2008) 328. [13] U. Husemann, Aging Effects and Operational Experience with the CDF Silicon Detector, to appear in the proceedings of Nuclear Science Symposium, IEEE Conference Dresden, Oct 20-Oct 24, [14] V. Cindro, et al., The ATLAS Beam Condition Monitor, JINST 3 (2008) P [15] project description.html [16]

20 Biographical Sketch: Harris Kagan Harris Kagan is an experimentalist specializing in high energy physics. His interests are in B-decays, tau-decays, detector development and diamonds. From Dr. Kagan was a postdoctoral researcher for the University of Rochester s CLEO group. His CLEO responsibilities included the construction, maintenance and operation of the detector s muon system as well as the analysis software used by this system. These devices played a crucial role in the first observation of the decay of the B meson into muons. In 1981 Dr. Kagan joined the faculty of The Ohio State University. He continued as a member of the CLEO collaboration until Along with members of the OSU/CLEO group he made major hardware contributions to three generations of high resolution drift chamber systems, the CLEO II calorimeter electronics readout system, and was the project leader for the CLEO III silicon detector. His analysis efforts included the measurement of the lifetime of the τ-lepton and charmed mesons, in addition to measurements of the branching ratio of B-mesons. Dr. Kagan was a founding member and Co-Spokesperson of both DIAMAS and RD42, two projects with the goal of developing CVD diamond for particle tracking detectors. Since 1998 he has been a member of the ATLAS collaboration. In he spent a year at CERN working on the ATLAS Silicon tracker. In May of 2002 Dr. Kagan became a member of the BaBar collaboration to continue his interest in B-decays. His hardware contribution to BaBar was the construction of the diamond beam conditions monitor - the first such diamond device in any high energy physics experiment. This device was ground breaking in that it showed that diamonds were a viable detector material. Every LHC experiment now has some form of diamond detector. For ATLAS he constructed the diamond beam condition monitor and diamond beam loss monitor. Education 1972 State University of New York at Stoney Brook B.S. Physics 1979 University of Minnesota Ph.D. High Energy Physics Positions: Research Associate, University of Rochester Assistant Professor, The Ohio State University Associate Professor, The Ohio State University 1991 Visiting Scholar, Harvard University 1990-Present Professor (Physics), The Ohio State University 1995-Present Professor (Art), The Ohio State University Scientific Associate, CERN, European Organization for Nuclear Research Honors: 1984 DOE Outstanding Junior Investigator Award 1992 Center for Teaching Excellence (OSU) Award 1994 Battelle Endowment for Science and Technology Award 2002 Fellow of the American Physical Society 19

21 Other Experience and Professional Service: 1994-Present Co-Spokesperson, CERN RD42 Experiment 1994 Member of DOE (Lehman) Review of SLAC (B-Factory) 1995 Member of DOE (Lehman) Review of SLAC (BaBar Experiment) 1996 Member of DOE (Lehman) Review of Fermilab (D0 Experiment) 1997 Organizing Committee, 3rd International Meeting on Front End Electronics for High Resolution Tracking Detectors, Taos, NM 1998 Member, External Review Committee of Purdue University Physics Program 1998 Member, External Review Committee of LBNL Physics Program, Berkeley, CA Organizing Committee, 2rd, 3rd, 4th, 5th and 6th International Conferences on Radiation Effects in Semiconductor Materials, Detectors, and Devices, Florence, Italy 2001 Scientific Advisory Committee, 9th Vienna Instrumentation Conference 2005 Organizing Committee, PASCOS 2006, Columbus, Ohio Selected Peer-Reviewed Publications: (Publications selected from over 750 peer-reviewed publications) 1. Development of Diamond Radiation Detectors for SSC and LHC, Nucl. Instr. and Meth. A315, 39 (1992), (with M. Franklin, et al.). 2. Thickness Dependence of the Electrical Characteristics of Chemical Vapor Deposited Diamond Films, Appl. Phys. Lett. 62, 193 (1994), (with M.A. Plano, et al.). 3. First Measurements with a Diamond Microstrip Detector, Nucl. Instr. and Meth. A354, 318 (1995), (with F. Borchelt, et al.). 4. Radiation Hardness Studies of CVD Diamond Detectors, Nucl. Instr. and Meth. A367, 207 (1995), (with H. Pernegger, et al.). 5. Low Noise Electronics for the CLEO III Silicon Detector, Nucl. Instr. and Meth. A383, 189 (1996), (H. Kagan, et al.). 6. The First Bump-bonded Pixel Detector on CVD Diamond, Nucl. Instr. and Meth. A436, 326 (1999), (with W. Adam, et al.). 7. Performance of Irradiated CVD Diamond Micro-strip Sensors, Nucl. Instr. and Meth. A476, 706 (2002), (with W. Adam, et al.). 8. Charge-carrier Properties in Synthetic Single-crystal Diamond Measured with the Transientcurrent Technique, J. Appl. Phys. 97, (Apr. 2005), (with H. Pernegger et al.). Recent Collaborators: P. Burchat (Stanford), A. Gorisek (Ljubljana), E. Greismeier (Vienna), M. Mathes (Bonn), M. Mikuz (Ljubljana), H. Pernegger (CERN), B. Petersen (CERN), S. Schnetzer (Rutgers), B. Stone (Rutgers), J. Velthius (Liverpool), P. Weilhammer (CERN), N. Wermes (Bonn). I am also a collaborator of ATLAS, BaBar and RD42. 20

22 Current and Pending Support: Harris Kagan Project/Proposal Title: Research in Elementary Particle Physics, Task D Source of Support: DOE Total Award Amount: $663,000 Total Award Period Covered: 12/01/08-11/30/09 Co-PI s: K.K. Gan, R. Kass, K. Honscheid Status: Current Project/Proposal Title: ATLAS Optolink Upgrade R&D Source of Support: DOE Total Award Amount: $110,000 Total Award Period Covered: 12/01/08-11/30/09 Co-PI s: K.K. Gan, R. Kass Status: Current Project/Proposal Title: Radionuclides: Radiation Detection and Quantification Source of Support: U. of Michigan Total Award Amount: $368,097 Total Award Period Covered: 9/01/06-7/31/09 Co-PI s: K. Honscheid Status: Current 21

23 Biographical Sketch: Richard Kass Richard Kass is an experimentalist specializing in high energy physics. As a graduate student at UC Davis he was involved in a series of Fermilab bubble chamber experiments using high energy ( GeV) protons and pions. His Ph. D. thesis research ( ) studied 400 GeV proton-proton collisions using the Fermilab 15 foot bubble chamber. From Dr. Kass was a postdoctoral researcher for Cornell University stationed at Fermilab. He was a member of E553, a charm search experiment using a neutrino beam. From 1980 to 1983 Dr. Kass was a postdoctoral researcher for the University of Rochester s CLEO group. His CLEO responsibilities included the maintenance and operation of the detector s low pressure cherenkov counters as well as the analysis software used by this system. These devices played a crucial role in the first observation of the decay of the B meson into electrons. In 1983 Dr. Kass joined the faculty of The Ohio State University. He continued as a member of the CLEO collaboration until During his time on CLEO he served on every major collaboration committee as well as holding the office of spokesman and analysis coordinator. Along with members of the OSU/CLEO group he made major hardware contributions to three generations of high resolution drift chamber systems, the CLEO II calorimeter electronics readout system, and the CLEO III silicon power supply system. His analysis efforts included the measurement of the lifetime of the τ-lepton, charmed mesons, and charmed baryons in addition to numerous branching ratio measurements. Dr. Kass was a founding member of both DIAMAS and RD42, two projects with the goal of developing CVD diamond for particle tracking detectors. Since 1998 he has been a member of the ATLAS collaboration and has concentrated his research efforts on the optical readout of the pixel detector. In May of 2002 Dr. Kass became a member of the BaBar collaboration. Dr. Kass presently serves as the DOE Contact/PI for The Ohio State University DOE grant. Education 1972 State University of New York at Albany B.S. Physics 1978 University of California, Davis Ph.D. High Energy Physics Positions: Research Associate, Cornell University Research Associate, University of Rochester Assistant Professor, The Ohio State University Associate Professor, The Ohio State University 1992-Present Professor (Physics), The Ohio State University Honors: 1976 Earle C. Anthony Fellowship Award 1985 DOE Outstanding Junior Investigator Award 2004 Fellow of the American Physical Society 22

24 Other Experience and Professional Service: Member, CLEO Collaboration Analysis Coordinator of the CLEO Experiment Spokesman of the CLEO Experiment 1986 Member of SSC Central Design Group at LBNL Member of AMY collaboration 1991 Chairman, Organizing Committee, Future Direction in B Physics 1992 Member, Organizing Committee, 2nd Workshop on Tau Lepton Physics Member of DIAMAS collaboration 1994-Present Member of RD Present Member of ATLAS 2002-Present Member of BaBar Selected Peer-Reviewed Publications: 1. Measurement of the D 0, D +, and D + s Meson Lifetimes, Phys. Lett. B191, 318 (1987), (with C.Csorna, et al.). 2. Measurement of the Tau Lifetime, Phys. Rev. D36, 690 (1987), (with C. Bebek, et al.). 3. Development of Diamond Radiation Detectors for SSC and LHC, Nucl. Instr. and Meth. A315, 39 (1992), (with M. Franklin, et al.). 4. First Measurements with a Diamond Microstrip Detector, Nucl. Instr. and Meth. A354, 318 (1995), (with F. Borchelt, et al.). 5. Radiation Hardness Studies of CVD Diamond Detectors, Nucl. Instr. and Meth. A367, 207 (1995), (with H. Pernegger, et al.). 6. The First Bump-bonded Pixel Detector on CVD Diamond, Nucl. Instr. and Meth. A436, 326 (1999), (with W. Adam, et al.). 7. Design and Initial Performance of the CLEO III Silicon Tracker, Nucl. Instr. and Meth. A473, 17 (2001), (with E. von Toerne, et al.). 8. Performance of Irradiated CVD Diamond Micro-strip Sensors, Nucl. Instr. and Meth. A476, 706 (2002), (with W. Adam, et al.). 9. The Power Supply System of the CLEO III Silicon Detector, Nucl. Instr. and Meth. A481, 538 (2002), (with E. von Toerne, et al.). Recent Collaborators: M. Bruinsma (Irvine), P. Burchat (Stanford), A. Clark (U. Geneva), E. Greismeier (Vienna), T. Lari (Bonn), H. Pernegger (CERN), B. Petersen (Stanford), S. Schnetzer (Rutgers), B. Stone (Rutgers), J. Velthius (Bonn), P. Weilhammer (CERN), N. Wermes (Bonn). I am also a collaborator of ATLAS, BaBar and RD42. 23

25 Current and Pending Support: Richard Kass Project/Proposal Title: Research in Elementary Particle Physics, Task D Source of Support: DOE Total Award Amount: $663,000 Total Award Period Covered: 12/01/08-11/30/09 Co-PI s: K.K. Gan, R. Kass, K. Honscheid Status: Current Project/Proposal Title: ATLAS Optolink Upgrade R&D Source of Support: DOE Total Award Amount: $110,000 Total Award Period Covered: 12/01/08-11/30/09 Co-PI s: K.K. Gan, R. Kass Status: Current 24

26 Biographical Sketch: K.K. Gan Dr. K.K. Gan is an experimentalist specializing in high energy physics. He did his Ph.D. thesis (1980-5) on the study of the tau lepton using the HRS detector at PEP (SLAC). He maintained the trigger system for the experiment. From he was a postdoctoral researcher at SLAC as a member of the MARK II experiment at both PEP and SLC. He led the design of the vertex detector trigger for the SLC. In 1990 Dr. Gan joined the faculty of The Ohio State University. He was a member of the CLEO collaboration until He led the study of helium based gases for the CLEO III drift chamber. The study demonstrated the feasibility of using helium based gases and consequently the CLEO II drift chamber gas was also switched to a helium based gas. He also led the research and development of the chip carrier board (hybrid) for the CLEO III silicon vertex detector. He observed several rare decays of the tau lepton and set new upper limits on many forbidden decays. Since 1998 he has been a member of the ATLAS collaboration and led the research efforts on the optical electronics of the pixel detector. In May 2002 Dr. Gan became a member of the BaBar collaboration. Education 1980 Royal College of Science, Imperial College, London B.Sc. Physics 1985 Purdue University, Lafayete, Indiana Ph.D. High Energy Physics Positions: Research Associate, Stanford Linear Accelerator Center Assistant Professor, The Ohio State University Associate Professor, The Ohio State University 2001-Present Professor (Physics), The Ohio State University Honors: 1980 First Class Honours in B.Sc Associateship of Royal College of Science 1983 David Ross Fellowship, Purdue University 1991 SSC National Fellowship 1991 DOE Outstanding Junior Investigator Award 25

27 Other Experience and Professional Service: Member, CLEO Collaboration 1991 Member, Organizing Committee, Future Directions in B Physics 1992 Chairman, Organizing Committee, 2nd Workshop on Tau Lepton Physics Member, Organizing Committee, 3rd, 4th, 5th, 6th and 7th Workshops on Tau Lepton Physics 1994-Present Member of RD Present Member of ATLAS 2002-Present Member of BaBar Selected Peer-Reviewed Publications: 1. Development of Diamond Radiation Detectors for SSC and LHC, Nucl. Instr. and Meth. A315, 39 (1992), (with M. Franklin, et al.). 2. Thickness Dependence of the Electrical Characteristics of Chemical Vapor Deposited Diamond Films, Appl. Phys. Lett. 62, 193 (1994), (with M.A. Plano, et al.). 3. First Measurements with a Diamond Microstrip Detector, Nucl. Instr. and Meth. A354, 318 (1995), (with F. Borchelt, et al.). 4. Radiation Hardness Studies of CVD Diamond Detectors, Nucl. Instr. and Meth. A367, 207 (1995), (with H. Pernegger, et al.). 5. Study of Helium-based Drift Chamber Gases, Nucl. Instr. and Meth. A374, 27 (1996), (with K.K. Gan et al.). 6. Low Noise Electronics for the CLEO III Silicon Detector, Nucl. Instr. and Meth. A383, 189 (1996), (H. Kagan, et al.). 7. Incorporation of the Statistical Uncertainty in the Background Estimate into the Upper Limit on the Signal, Nucl. Instr. and Methods. A412, 475 (1998). 8. The First Bump-bonded Pixel Detector on CVD Diamond, Nucl. Instr. and Meth. A436, 326 (1999), (with W. Adam, et al.). 9. Design and Initial Performance of the CLEO III Silicon Tracker, Nucl. Instr. and Meth. A473, 17 (2001), (with E. von Toerne, et al.). 10. Performance of Irradiated CVD Diamond Micro-strip Sensors, Nucl. Instr. and Meth. A476, 706 (2002), (with W. Adam, et al.). Recent Collaborators: M. Bruinsma (Irvine), P. Burchat (Stanford), A. Clark (U. Geneva), E. Greismeier (Vienna), T. Lari (Bonn), H. Pernegger (CERN), B. Petersen (Stanford), S. Schnetzer (Rutgers), B. Stone (Rutgers), J. Velthius (Bonn), P. Weilhammer (CERN), N. Wermes (Bonn). I am also a collaborator of ATLAS, BaBar and RD42. 26