Development of novel photon detectors at UC Davis Ferenc, D.; Kranich, D.; Laille, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
11/2005, Letnik:
553, Številka:
1
Journal Article
Recenzirano
Photosensors are indispensable in many areas of fundamental physics research, particularly in the emerging field of particle astrophysics. They also find widespread use in medical imaging, nuclear ...radiation monitoring, and defense. To make significant progress in future, virtually all these areas require a new, inexpensive, high-quality industrial mass-production photosensor technology. Our group at UC Davis has been working on innovations along that line.
Commissioning and first tests of the MAGIC telescope Baixeras, C.; Bastieri, D.; Bigongiari, C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
02/2004, Letnik:
518, Številka:
1
Journal Article
Recenzirano
Major Atmospheric Gamma Imaging Cherenkov telescope is starting its operations with a set of engineering runs to tune the telescope subsystem elements to be ready for the first physics campaign. Many ...technical improvements have been developed and implemented in several elements of the telescope to reach the lowest energy threshold ever obtained by an Imaging Atmospheric Cherenkov Telescope. A general description of the telescope is presented. The commissioning of the telescope's elements is described and the expected performances are reviewed with the final detector set-up.
First ReFerence photosensor prototype Ferenc, Daniel; Laille, Alvin; Bratton, Clayton
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2003, Letnik:
504, Številka:
1-3
Journal Article
Recenzirano
First test results of the ReFerence photosensor prototype are presented. The results verify the basic design feature, i.e. the photoelectron focusing from the entire photocathode to the small region ...in the middle of the entrance window of the ReFerence tube.
Beryllium is a suitable candidate for plasma facing components (PFC) such as divertor or first wall in the ITER project. Due to their high thermal conductivity, copper alloys are used as the heat ...sink material. Consequently, use of beryllium requires that it has to be joined to the Cu heat sink by some method. In this study, the joining of beryllium onto the copper alloy Glidcop
® is achieved by hot isostatic pressing diffusion bonding (HIPB). This joining technique allows a homogeneous bonding. As direct bonding between Be and Cu alloy induces intermetallics that are deleterious to the joint, an interlayer is placed between the two materials. The interlayer has been chosen regarding the metallurgical structure and the mechanical properties of beryllium relatively to the Glidcop
® alloy. This paper describes the structure of joints performed with the help of HIPB at temperature higher than 800°C.
Ground-based Cherenkov telescopes have made in recent years important contributions to high energy gamma-ray astronomy. A lower energy threshold, considerably below 100
GeV, and improved sensitivity ...will be key parameters to extend their role. A lower threshold will permit these instruments to cover wavelengths with good overlap with satellite experiments, thus providing essential complementary information.
The latest generation of Imaging Air Cherenkov Telescopes was built with this criterion in mind. Preliminary studies concerning further progress in the same direction have started.
We discuss in this contribution the astrophysics and physics arguments for lowering the observable energy threshold as far as the Cherenkov technique permits, and the ensuing complementarity to results obtained with a GLAST-like satellite.
Astrophys.J.642:L119-L122,2006 The MAGIC collaboration has studied the high peaked BL-Lac object
1ES1218+30.4 at a redshift z = 0.182, using the MAGIC imaging air Cherenkov
telescope located on the ...Canary island of La Palma. A gamma-ray signal was
observed with 6.4sigma significance. The differential energy spectrum for an
energy threshold of 120GeV can be fitted by a simple power law yielding F_E(E)
= (8.1+-2.1)*10^-7 (E/250GeV)^(-3.0+-0.4) TeV^-1 m^-2 s^-1. During the six days
of observation in January 2005 no time variability on time scales of days was
found within the statistical errors. The observed integral flux above 350GeV is
nearly a factor two below the the upper limit reported by the Whipple
Collaboration in 2003.
Astrophys.J.641:L9-L12,2006 The long-duration GRB050713a was observed by the MAGIC Telescope, 40 seconds
after the burst onset, and followed up for 37 minutes, until twilight. The
observation, ...triggered by a SWIFT alert, covered energies above ~175 GeV. Using
standard MAGIC analysis, no evidence for a gamma signal was found. As the
redshift of the GRB was not measured directly, the flux upper limit, estimated
by MAGIC, is still compatible with the assumption of an unbroken power-law
spectrum extending from a few hundred keV to our energy range.
The MAGIC collaboration has studied the high peaked BL-Lac object 1ES1218+30.4 at a redshift z = 0.182, using the MAGIC imaging air Cherenkov telescope located on the Canary island of La Palma. A ...gamma-ray signal was observed with 6.4sigma significance. The differential energy spectrum for an energy threshold of 120GeV can be fitted by a simple power law yielding F_E(E) = (8.1+-2.1)*10^-7 (E/250GeV)^(-3.0+-0.4) TeV^-1 m^-2 s^-1. During the six days of observation in January 2005 no time variability on time scales of days was found within the statistical errors. The observed integral flux above 350GeV is nearly a factor two below the the upper limit reported by the Whipple Collaboration in 2003.
