Hartmut F.-W. Sadrozinski's research while affiliated with University of California, Santa Cruz and other places

Publications (41)

Article
AC-LGADs, also referred to as resistive silicon detectors, are a recent development of low-gain avalanche detectors (LGADs), based on a sensor design where the multiplication layer and n+ contact are continuous, and only the metal layer is patterned. In AC-LGADs, the signal is capacitively coupled from the continuous, resistive n+ layer over a diel...
Preprint
Full-text available
In the past few years, the need of measuring accurately the spatial and temporal coordinates of the particles generated in high-energy physics experiments has spurred a strong R\&D in the field of silicon sensors. Within these research activities, the so-called Ultra-Fast Silicon Detectors (UFSDs), silicon sensors optimized for timing based on the...
Preprint
For the Phase-II Upgrade of the ATLAS Detector, its Inner Detector, consisting of silicon pixel, silicon strip and transition radiation sub-detectors, will be replaced with an all new 100 % silicon tracker, composed of a pixel tracker at inner radii and a strip tracker at outer radii. The future ATLAS strip tracker will include 11,000 silicon senso...
Article
We report on the design, fabrication, and first tests of a tomographic scanner developed for proton computed tomography (pCT) of head-sized objects. After extensive preclinical testing, pCT is intended to be employed in support of proton therapy treatment planning and pre-treatment verification in patients undergoing particle-beam therapy. The scan...
Article
Full-text available
Radiation therapy with protons and heavier ions is an attractive form of cancer treatment that could enhance local control and survival of cancers that are currently difficult to cure and lead to less side effects due to sparing of normal tissues. However, particle therapy faces a significant technical challenge because one cannot accurately predic...
Patent
A method of singulating semiconductor devices in the close proximity to active structures by controlling interface charge of semiconductor device sidewalls is provided that includes forming a scribe on a surface of a semiconductor devices, where the scribe is within 5 degrees of a crystal lattice direction of the semiconductor device, cleaving the...
Article
Transient current technique (TCT) measurements with focused laser light on miniature silicon strip detectors (n+-type strips on p-type bulk) with one inactive edge thinned to about 100 µm using the Scribe-Cleave-Passivate (SCP) method are presented. Pulses of focused IR (λ=1064 nm) laser light were directed to the surface of the detector and charge...
Article
Selected particle detectors are described which find an application in medicine and have been the topic of presentations at the 2013 Vienna Conference of Instrumentation (VCI).
Conference Paper
In support of developing the next phase of a proton computed tomography (pCT) scanner with features making it applicable to clinical situations, much insight can be gained through Monte Carlo simulation using Geant4. Careful simulation of energy/range detectors, as well as silicon strip detectors (SSDs), has offered insights into the physical limit...
Conference Paper
We present a data acquisition design for a silicon-strip tracking system being constructed as part of a pre-clinical prototype scanner for proton computed tomography (pCT), capable of measuring one to two million proton tracks per second. The front end of the system is based on our ASIC design that handles 64 consecutive channels, including logic f...
Conference Paper
Full-text available
CONCLUSION Proton CT has the potential to substantially improve the range accuracy of proton beams and to provide a low-dose imaging modality for daily image guidance. Careful evaluation of this novel technique is underway. BACKGROUND Proton CT is a novel tomographic imaging modality, which has become a realistic possibility with the increasing av...
Article
We have investigated the layout for the inner tracking detector for ATLAS at the high luminosity upgrade of the LHC with respect to radiation damage and occupancy. Using simulated particle fluxes, we evaluate the signal-to-noise ratio based on measured radiation damage data, and estimate the expected occupancy. Tracking performance simulations yiel...
Conference Paper
BACKGROUND Proton CT can provide improved dose accuracy in treatment planning for proton therapy. In addition, lower doses than X-ray CT are theoretically possible and streaking artifacts will be reduced or eliminated. The first proton CT scanner has now been tested in a proton beam and the results are presented. This paper focuses on the detector...
Conference Paper
The existing pixel tracking detectors of ATLAS and CMS experiments will have to be replaced after LHC luminosity upgrade (super-LHC or sLHC), due to increased radiation level and tracking performance requirements. We are studying device active area re-optimization by cutting away dead area and some of the guard rings of existing sensors. Performanc...
Article
Bump bonding is the standard approach for flexible PDMS bumps should allow good contacts to these connecting pixel sensors with read-out ASICS. Current fine- and other brittle materials. pitch bump bonds lead to permanent bonds. We use photo-patternable silicone (polydimethylsiloxane, or PDMS) in combination with a metal coating to generate flexibl...
Article
Proton therapy is a precise forms of radiation therapy that makes use of high energy proton compared to the conventional, more commonly used and less precise x-ray and electron beams. On the other hand, to fully exploit the proton therapy advantages, very accurate quality controls of the treatments are required. These are mainly related to the dose...
Conference Paper
Full-text available
We investigate the response of SiGe HBTs exposed to high fluence and total dose levels of proton, neutron and gamma irradiation typically encountered in high energy physics experiments. The transistor radiation tolerance is evaluated via a comparison of excess base current, base current ideality, and current gain degradation. The results indicate t...
Article
The need for ultra-radiation hard semiconductor detectors for the inner tracker regions in high energy physics experiments of the future generation can be satisfied either with materials which are inherently more radiation hard than float zone silicon or with special detector structures with improved radiation resistance. This report compares direc...
Article
As part of a program to investigate the feasibility of proton computed tomography, the most likely path (MLP) of protons inside an absorber was measured in a beam experiment using a silicon strip detector set-up with high position and angular resolution. The locations of 200 MeV protons were measured at three different absorber depth of PolyMethylM...
Article
The plans for an upgrade of the Large Hadron Collider LHC to the Super-LHC (sLHC) are reviewed with special consideration of the environment for the inner tracking system. A straw-man detector upgrade for ATLAS is presented, which is motivated by the varying radiation levels as a function of radius, and choices for detector geometries and technolog...
Article
The plans for an upgrade of the Large Hadron Collider (LHC) to the Super-LHC (sLHC) are reviewed with special consideration of the environment for the inner tracking system. A straw-man detector upgrade for ATLAS is presented, which is motivated by the varying radiation levels as a function of radius, and choices for detector geometries and technol...
Article
We have designed and developed the flight model silicon micro-strip detector (FM-SSD) for Large Area Space Telescope (GLAST). The concepts and details of the sensor design are described and the results of production testing of the SSDs are reported. A total of 11,500 FM-SSDs were produced in the 2-yr time span from the start of 2001 to the end of 2...
Article
Full-text available
Proton therapy, long regarded as a superior method of radiation therapy, is now becoming more cost effective and is being used in a number of clinical centers around the world. In light of this development the use of the proton beam itself should be considered for the most accurate method of treatment planning. X-ray computed tomography (XCT), whic...
Conference Paper
Full-text available
A novel position- and energy-sensitive particle detector for radiobiological application is described. The aim is to support research in radiation response of biological systems, for example in the induction of mutations in C elegans, where precise knowledge of location and intensity of the radiation is crucial to understand radiation sensitivity o...
Article
Topics in radiation effects in life sciences are reviewed with special attention to communality with radiation effects in device physics.
Article
Full-text available
The position- and energy-sensitive primary particle detectors of a nanodosimetry system are described. They consist of a telescope of silicon strip detectors, which allow the determination of the particle's position from the hit strip address and its energy from the specific energy loss. In our implementation, the energy loss is measured through th...
Article
The GLAST large area telescope instrument has been designed for high sensitivity, high precision gamma-ray detection in space. It will contain more than 80 m2 of single-sided AC-coupled silicon detectors. The use of silicon detectors in space will pose special challenges for the design, testing and operation, among them attention to radiation issue...
Article
The principle of operations and the development and applications of silicon detectors are discussed. The application of strip detectors in high-energy physics follows Moore's law in both the area and the channel count. New developments include pixel and drift detectors. Examples of use in space sciences and the growing use in medical applications a...
Article
The GLAST LAT instrument has been designed for high precision gamma-ray detection in space. It will contain more than 80 m2 of single-sided AC-coupled silicon detectors. The design of the instrument will be described, and the predicted performance will be traced back to the scientific goals of the GLAST mission. The application in space will requir...
Article
A large-scale application of silicon-strip detector technology is planned in the satellite-based gamma-ray telescope GLAST. The design and expected performance of the silicon detectors both for triggering and gamma-ray tracking is described. The size of the instrument and the special environment of launch and orbit in space require an R&D program,...
Article
The development of silicon microstrip detectors for high luminosity application at the Large Hadron Collider (LHC) is described. The technical choices are most severely restricted by the anticipated radiation damage. A radiation-tolerant choice for the silicon tracker of the LHC detector ATLAS are sandwiches of single-sided detectors with n-strips...
Article
Recent developments of colliding beam detectors are reviewed. Similarities are discussed in terms of common physics goals and non-physics constraints. As an extrapolation of present technologies the development of a low-mass drift chamber is discussed. As an example of a much larger extrapolation of present technologies to the next generation of co...
Article
We have designed and fabricated through MOSIS two amplifier-comparator chips using BICMOS technology for use with silicon strip detectors. The chips use BJT.JFET.MOSFET, and capacitor devices, BJT-MOS and BJT-JFET based amplifiers and comparators are implemented in various configurations. The resulting amplifiers provide good performance at less th...
Article
The SSC is a high luminosity hadron collider and produces high data rates. Extensive data processing and storage will be required close to the detector elements before the read‐out of the entire event. We will review different ‘‘generic’’ front‐end architectures for various detector subsystems. A few challenging technical questions like interconnec...
Article
We analyze some of the existing data available for the hadronic and radiative production of mesons from the J/psi. A reanalysis of the decays into a pseudoscalar- and vector-meson pair indicates good agreement with the pseudoscalar mixing angle derived from the new two-photon widths of these mesons. An important ingredient is the inclusion of the d...
Article
Breakdown phenomena characterized by large currents in multiwire chambers were simulated and measured in a small multiwire cell. A variety of breakdown tests were performed, using different gas mixtures, gains, and wire diameters. It was found that the breakdown was well described by the product of the separate anode and cathode wire gains exceedin...
Article
The electrostatic conditions for which breakdown occurs in multiwire chambers are investigated as a function of wire thickness and the total gain in the system.
Article
The design of the new cylindrical drift chamber for the Mark II detector at the SLAC Linear Collider is described. Prototype tests to determine the working parameters of the chamber and to study possible gas mixtures are discussed.
Article
Based on recent data of radiation effects in p-type detectors, the expected performance of planned short silicon strip detectors (SSSD) in the ATLAS upgrade tracking detector are evaluated. The signal-to-noise ratio and power generated will be presented as a function of a set of realistic values for the operating parameters: fluence (3·1014, 1·1015...

Citations

... A major breakthrough in 4D tracking detector technology in recent years has been the development of silicon based sensors such as AC-coupled Low Gain Avalanche Detectors (AC-LGAD) [8][9][10][11]. These sensors have been demonstrated to be capable of achieving 30 ps time resolution and 5-30 µm position resolution [12][13][14][15]. ...
... The ultimate goal would be to finish the image capturing within the minimum gantry rotation time. The LLU/UCSC Phase-II Scanner prototype detector showed speed up to 1.2 million proton per second, which probably can be upgraded with 50% in the near future (Robert P. Johnson et al., 2016). To increase the data taking rate to 10 million protons per second, two possible directions exist: the first is to apply faster readout frequency of 10 MHz at least, the second is to measure multiple proton tracks within one readout frame. ...
... To compute the covariance matrices, we used a spatial resolution of σ t = 0.066 mm corresponding to a strip pitch of 228 µm, a material budget of x/X 0 = 5 × 10 −3 and a distance d T = 10 cm between the trackers in each pair. These values meet or exceed the minimum specifications for pCT scanner prototypes as detailed in [18]. The closest trackers of each pair were placed at a distance of 40 cm from the isocenter, which corresponds to distances used in commercial X-ray CT scanners [10]. ...
... The collected charge at a given bias voltage is calculated by integrating the current signal over time. On performing a voltage sweep at a given position on the sensor optically exposed to the laser beam, the saturation of the collected charge beyond a certain bias can be interpreted as the onset of full depletion of the sensor (Eremin et al., 1996;Fretwurst et al., 1997;Mandić et al., 2015Mandić et al., , 2013Mandić et al., , 2014. ...
... MHz with the silicon trackers[Sadrozinski et al., 2011Steinberg et al., 2012;Johnson et al., 2012Johnson et al., , 2013. This requirement has been estimated for the synchrotron beam of the Loma Linda Univesity Medical Center: proton bunches are spaced by 110 ns intervals, and only single-proton bunches can be used because of the particle rate supported by the calorimeter. ...
... The detector systems required for proton CT are technically challenging, complex and costly to build. Thus, MC simulations have been extensively used for the design and optimization of such detectors (Giacometti et al., 2017;Lee et al., 2016;Steinberg et al., 2012). ...
... Equation (4) indicates that to achieve performance close to the theoretical limit of range straggling, a calorimeter WEPL detector should provide an energy resolution better than 1% from a few tens of MeV to a few hundreds of MeV, a performance level that is not easy to achieve, especially with a fast detector. 6 An alternative approach to measuring WEPL is to build a detector with a large number of stages of a few mm in thickness (n ≫ 10, i.e., a true range counter), as described, e.g., in Refs. 7 and 8. Assuming only small scattering angles within the material, the range R is approximately defined by the center position of the stage i where the last energy deposition is detected, in which case Eq. (1) becomes ...
... Several other factors may facilitate its ignition, such as highly ionizing particles, sparks, sharp points on electrodes causing corona discharges, or thin anode wires [15]. It is easy to ignite Malter currents in a detector operating with hydrocarbon gases at elevated high voltages [18] or forcing chambers to breakdown [19][21], and in a detector, which has been previously exposed to TMAE gas [22]. The CRID RICH detector [23] with an excellent 3-dimensional single electron reconstruction capability allowed the first imaging of the onset of the Malter effect, which starts from sporadic bursts of single electrons from a localized cathode spot [22]. ...
... , shows the collected charge as a function of bias voltage after 70 MeV/c proton, 280 MeV/c pion and reactor neutron irradiations to 1.2 × 10 15 n eq cm −2 , which is the highest expected fluence, including a two times safety factor, for the innermost strip barrel sensor. As the estimated noise for the innermost strip barrel module at the end of lifetime is 610 e [10], a signal-to-noise at the expected operating bias voltages of 500 V is roughly 15 with no annealing, which could be enhanced with annealing to approximately 20 [11]. This level of signal-to-noise is sufficient for high signal efficiency and low noise occupancy. ...
... The AC coupling is obtained using a silicon oxide layer between the implant strip and the floating metal strip. To prevent microdischarge at the edges, the metal strip covers the implant strip edges with a 4-µm overhang [25]. In addition, the AC pads and DC pads of the sensor allow testing access to the metal strip and the implant strip, respectively. ...