X‐ray free‐electron lasers (XFELs) deliver pulses of coherent X‐rays on the femtosecond time scale, with potentially high repetition rates. While XFELs provide high peak intensities, both the ...intensity and the centroid of the beam fluctuate strongly on a pulse‐to‐pulse basis, motivating high‐rate beam diagnostics that operate over a large dynamic range. The fast drift velocity, low X‐ray absorption and high radiation tolerance properties of chemical vapour deposition diamonds make these crystals a promising candidate material for developing a fast (multi‐GHz) pass‐through diagnostic for the next generation of XFELs. A new approach to the design of a diamond sensor signal path is presented, along with associated characterization studies performed in the XPP endstation of the LINAC Coherent Light Source (LCLS) at SLAC. Qualitative charge collection profiles (collected charge versus time) are presented and compared with those from a commercially available detector. Quantitative results on the charge collection efficiency and signal collection times are presented over a range of approximately four orders of magnitude in the generated electron–hole plasma density.
Two approaches to the design of a diamond sensor signal path were explored using high‐intensity X‐ray pulses from the LINAC Coherent Light Source at SLAC. Results on the charge‐collection efficiency and signal collection time are presented over a range of approximately four orders of magnitude in the generated electron–hole plasma density.
Low Gain Avalanche Diodes (LGADs) are thin (20-50
μm
) silicon diode sensors with modest internal gain (typically 5 to 50) and exceptional time resolution (17
ps
to 50
ps
). However, the granularity ...of such devices is limited to the millimeter scale due to the need to include protection structures at the boundaries of the readout pads to avoid premature breakdown due to large local electric fields. Here, we present a new approach – the Deep-Junction LGAD (DJ-LGAD) – that decouples the high-field gain region from the readout plane. This approach is expected to improve the achievable LGAD granularity to the tens-of-micron scale while maintaining direct charge collection on the segmented electrodes.
Experimental Study of Acceptor Removal in UFSD Jin, Y.; Ren, H.; Christie, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2020, Letnik:
983, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The performance of the Ultra-Fast Silicon Detectors (UFSD) after irradiation with neutrons and protons is compromised by the removal of acceptors in the thin layer below the junction responsible for ...the gain. This effect is tested both with capacitance–voltage, C–V, measurements of the doping concentration and with measurements of charge collection, CC, using charged particles. We find a perfect linear correlation between the bias voltage to deplete the gain layer determined with C–V and the bias voltage to collect a defined charge, measured with charge collection. An example for the usefulness of this correlation is presented.
Next generation Low Gain Avalanche Diodes (LGAD) produced by Hamamatsu photonics (HPK) and Fondazione Bruno Kessler (FBK) were tested before and after irradiation with ~1MeV neutrons at the JSI ...facility in Ljubljana. Sensors were irradiated to a maximum 1-MeV equivalent fluence of 2.5E15 N
eq
/cm
2
. The sensors analysed in this paper are an improvement after the lessons learned from previous FBK and HPK productions that were already reported in precedent papers. The gain layer of HPK sensors was fine-tuned to optimize the performance before and after irradiation. FBK sensors instead combined the benefit of Carbon infusion and deep gain layer to further the radiation hardness of the sensors and reduced the bulk thickness to enhance the timing resolution. The sensor performance was measured in charge collection studies using β-particles from a 90Sr source and in capacitance-voltage scans (C-V) to determine the bias to deplete the gain layer. The collected charge and the timing resolution were measured as a function of bias voltage at -30C. Finally a correlation is shown between the bias voltage to deplete the gain layer and the bias voltage needed to reach a certain amount of gain in the sensor. HPK sensors showed a better performance before irradiation while maintaining the radiation hardness of the previous production. FBK sensors showed exceptional radiation hardness allowing a collected charge up to 10 fC and a time resolution of 40 ps at the maximum fluence.
PDF
