P. Dhez

The European Photon Imaging Camera on XMM-Newton: The pn-CCD camera

The European Photon Imaging Camera (EPIC) consortium has provided the focal plane instruments for the three X-ray mirror systems on XMM-Newton. Two cameras with a reflecting grating spectrometer in the optical path are equipped with MOS type CCDs as focal plane detectors (Turner 2001), the telescope with the full photon flux operates the novel pn-CCD as an imaging X-ray spectrometer. The pn-CCD camera system was developed under the leadership of the Max-Planck-Institut fur extraterrestrische Physik (MPE), Garching. The concept of the pn-CCD is described as well as the dierent operational modes of the camera system. The electrical, mechanical and thermal design of the focal plane and camera is briefly treated. The in-orbit performance is described in terms of energy resolution, quantum eciency, time resolution, long term stability and charged particle background. Special emphasis is given to the radiation hardening of the devices and the measured and expected degradation due to radiation damage of ionizing particles in the rst 9 months of in orbit operation.

The European Photon Imaging Camera on XMM-Newton: The MOS cameras

The EPIC focal plane imaging spectrometers on XMM-Newton use CCDs to record the images and spectra of celestial X-ray sources focused by the three X-ray mirrors. There is one camera at the focus of each mirror; two of the cameras contain seven MOS CCDs, while the third uses twelve PN CCDs, dening a circular eld of view of 30 0 diameter in each case. The CCDs were specially developed for EPIC, and combine high quality imaging with spectral resolution close to the Fano limit. A lter wheel carrying three kinds of X-ray transparent light blocking lter, a fully closed, and a fully open position, is tted to each EPIC instrument. The CCDs are cooled passively and are under full closed loop thermal control. A radio-active source is tted for internal calibration. Data are processed on-board to save telemetry by removing cosmic ray tracks, and generating X-ray event les; a variety of dierent instrument modes are available to increase the dynamic range of the instrument and to enable fast timing. The instruments were calibrated using laboratory X-ray beams, and synchrotron generated monochromatic X-ray beams before launch; in-orbit calibration makes use of a variety of celestial X-ray targets. The current calibration is better than 10% over the entire energy range of 0.2 to 10 keV. All three instruments survived launch and are performing nominally in orbit. In particular full eld-of-view coverage is available, all electronic modes work, and the energy resolution is close to pre-launch values. Radiation damage is well within pre-launch predictions and does not yet impact on the energy resolution. The scientic results from EPIC amply full pre-launch expectations.

XMM-Newton first-light observations of the Hickson galaxy group 16

This paper presents the XMM-Newton first-light observations of the Hickson-16 compact group of galaxies. Groups are possibly the oldest large-scale structures in the Universe, pre-dating clusters of galaxies, and are highly evolved. This group of small galaxies, at a redshift of 0.0132 (or 80 Mpc) is exceptional in the having the highest concentration of starburst or AGN activity in the nearby Universe. So it is a veritable laboratory for the study of the relationship between galaxy interactions and nuclear activity. Previous optical emission line studies indicated a strong ionising continuum in the galaxies, but its origin, whether from starbursts, or AGN, was unclear. Combined imaging and spectroscopy with the EPIC X-ray CCDs unequivocally reveals a heavily obscured AGN and a separately identified thermal (starburst) plasma, in NGC 835, NGC 833 and NGC 839. NGC 838 shows only starburst thermal emission. Starbursts and AGN can evidently coexist in members of this highly evolved system of merged and merging galaxies, implying a high probability for the formation of AGN as well as starbursts in post-merger galaxies.

X-Ray Laser Experiment with a Long Recombining-Plasma Column

We report the results of a soft-X-ray laser experiment in which five Nd-laser beams are used for producing a 6-cm long aluminium plasma column. Population inversion occurs for the 3d-5f transition of lithiumlike ions (λ = 105.7 A) according to the plasma recombination scheme. A double-pass device is achieved with a W/C multilayer mirror. Double-pass is shown to increase largely the intensity and the directivity of the beam at 105.7 A. A plasma produced from thin aluminium target supplies a gain coefficient of 0.5 cm-1, whereas population inversion is strongly reduced by radiation trapping in the case of massive targets.

Characterization of an x-ray laser beam

We report in this article the experimental and numerical tools, developed at the LSAI, for a complete characterization of an x-ray laser (XRL) beam. First, a Michelson interferometer has been used to realize a Fourrier transform spectroscopy experiment. A full comprehension of the measured linewidth requires a comparison of the XRL beam amplification in the plasma to raytrace simulation. Results of transient pumping XRL simulations are presented in this article. The last section is dedicated to a description of the XUV Shack-Hartmann wavefront sensor we have developed, and to the study of the capillary discharge XRL beam.

X‐UV gain amplification studies in laser plasma using normal incidence multilayers mirrors

Present state of art in multilayers mirrors and in population inversion in laser plasma permits to test possible laser cavity.

Experimental study of neonlike zinc J=0−1 soft X‐ray lasing at 21.2 nm

Since our first observation of intense J=0−1 lasing in neonlike zinc in early 1993, we have investigated various issues of this X‐ray laser. The results of these experiments, performed at Laboratoire pour l’Utilisation des Lasers Intenses (LULI), are briefly reviewed. Gain coefficients of ∼5 cm−1 at 21.2 nm are now routinely obtained with ≊350 J delivered onto a Zn slab in ∼650 ps pulses—the net irradiance is ∼1.4×1013 W cm−2. The 21.2 nm emission appears in a ≊100 ps burst and precedes the lasing on the J=2−1 transitions at 26.2 and 26.7 nm which have a duration ≊350 ps. We have directly measured the gain regions of the J=0−1 line at 21.2 nm and the J=2−1 line at 26.7 nm and confirmed the initial claim that they are located at different distances from the target. We have also measured the refraction angles and divergences of the XRL beams of these two transitions. The beam at 21.2 nm was observed to be remarkably narrow with a divergence of ∼2.6 mrad, peaking ∼7 mrad off‐axis. This contrasts to the beam ...

High gain‐production efficiency and large brightness X‐UV laser at Palaiseau

A large gain has been measured for the J=0–1 line of neonlike Zn at λ=21.2 nm. The time evolutions and the localization of emission zones of the J=0–1 and J=2−1 lines are compared. It is shown that a train of very small prepulses before the main pulse has an important role in the J=0=1 emission. A half‐cavity has been successfully used to attain a nearly saturated intensity with a 2 cm long plasma. The X‐UV pulse energy is of 400 μJ, the laser power of 5 MW. The driving laser is the 0.4 KJ, 600 ps laser of LULI.

2-D X-ray laser-plasma imaging using Bragg Fresnel multilayer zone plates

Abstract Two types of Bragg Fresnel multilayer zone plates operating in the keV range have been investigated for X-ray laser-plasma imaging. Elliptical on-axis and off-axis Bragg Fresnel multilayer zone plates were characterised. With the on-axis zone plate all the reflection orders are superposed in the same plane. The image contrast is then degraded as the zone plate focus distance is not the same for all orders. The problem is avoided with an off-axis zone plate with which the different orders in the image plane are spatially separated. The Al He α strong emission line (7.757 A) of a laser produced aluminium plasma has been selected for the imaging tests. The first order reflected intensity has been optimized by varying the Bragg and azimuthal angles. As a result, an X-ray image of a fine gold grid backlighted by the aluminium plasma emission has been obtained with a spatial resolution very close to the theoretical limit of the imaging mounting.

Collisionally excited X-ray laser schemes: progress at Rutherford Appleton Laboratory (Invited Paper)

Systematic study of the collisionally pumped Ne-like germanium 3p-3s laser system has led to the observation of saturated output on the J = 2-1 lines at 23.2 and 23.6 nm when a double slab target is double passed using a normal incidence concave mirror. The about-1-MW output power on the same lines from a simple double plasma has been used to record preliminary images with a Schwarzchild condenser and zone plate microscope arrangement. Initial analysis of measurements on the 4d-4p J = 1-0 line at 7.3 nm from nickel-like samarium indicate a gain coefficient of between 0.4/cm and 0.8/cm for an incident irradiance of about 2 x 10 exp 13 W/sq cm using a l.06-micron heating laser on slab targets of SmF3.