A Canted Double Undulator System with a Wide Energy Range for EMIL

At BESSY II a canted double undulator system for the Energy Materials In situ Laboratory EMIL is under construction. The energy regime is covered with two undulators, an APPLE II undulator for the soft and a cryogenic permanent magnet undulator CPMU 17 for the hard photons. The layout and the performance of the undulators are presented in detail. The minimum of the vertical betatron function is shifted to the center of the CPMU 17. The neighboring quadrupoles and an additional quadrupole between the undulators control the vertical betatron function. Prior to the undulator installation a testing chamber with four movable vertical scrapers has been implemented at the CPMU 17 location. Utilizing the scrapers the new asymmetric lattice optics will be tested and optimize

The status of the in vacuum APPLE II IVUE32 at HZB BESSY II

At BESSY II, two new beamlines for RIXS and for X Ray microscopy need a short period variably polarizing undulator. For this purpose, the first in vacuum APPLE II undulator worldwide is under construction. The parameters are as follows period length amp; 955;0 32 mm, periods 78, minimum gap 7mm. The design incorporates a force compensation scheme as proposed by two of the authors at the SRI 2018. All precision parts of the drive chain are located in air. New transverse slides for the transversal slit adjustment have been developed and tested. Optical Micrometers measure the gap and phase positions, similar to the system of the CPMU17 at BESSY II. They provide the signals for motor feedback loops. A new UHV compatible soldering technique, as developed with industry, relaxes fabrication tolerances of magnets and magnet holders and simplifies the magnet assembly. A 10 period prototype has been setup for lifetime tests of the new magnetic keeper design. The paper summarizes the status of the undulator IVUE3

Observation of hard scattering in photoproduction events with a large rapidity gap at HERA

Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the $\gamma p$ centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton.Comment: 19 pages, latex, 4 figures appended as uuencoded fil

Observation of direct processes in photoproduction at HERA

Jets in photoproduction events have been studied with the ZEUS detector for gammap centre-of-mass energies ranging from 130 to 2 50 GeV. The inclusive jet distributions give evidence for the dominance of resolved photon interactions. In the di-jet sample the direct processes are for the first time clearly isolated. Di-jet cross sections for the resolved and direct processes are given in a restricted kinematic range

A seamless control system upgrade for a continuously running accelerator facility

The control system of the Ion Beam Laboratory Berlin ISL Berlin dates from the late 1970 s and was originally designed for the HMI VICKSI accelerator complex. It is based on a single server processor PDP11 , a CAMAC fieldbus and software which was developed in house. The strategy for a control system upgrade has to face the request for continuing accelerator operation and the limited available manpower. The choice taken is the commercial product Vsystem by VISTA Inc. Accelerator specific applications can easily be generated on multiple OS platforms in a heterogeneous network by supplying transparent APIs as programming interface between the different control system layers. As Phase 1 of the upgrade, GUI s for operators or machine physicists have been implemented along with a Linux application server, collecting and archiving machine data, generating 24h trend charts, which are accessible via internet by standards browsers or WAP service, and sending alarm messages when requeste

The ISL control system upgrade A move from an in house implementation to a commercial control system

The control system of the ISL accelerator facility at the Hahn Meitner Institut Berlin is presently being converted and upgraded from a system which was developed in house to the commercially available Vsystem by VISTA Inc.. The upgrade plan for the continuously running facility has to cope with the maintenance of the installed hardware, with the maintenance of the old control system platform, the port of the knowledge base and tools contained in the old system to the new platform and the maintenance of the new platform. The maintenance includes updates due to modifications of the accelerator, accelerator components or of operational rules. All this has to be provided with as little interference with every day operation as possible. Both versions of the ISL control system, the old and the new VISTA based, will be operating in parallel for some interim time. As the porting of the old to the new platform does not foresee any coordination or inter communication between the ISL and VISTA data bases, applications within the new platform are only allowed read access to accelerator parameters in the Phase 1 approach. Active accelerator control is foreseen for Phase 2, by moving adequate parameter groups or accelerator sections in complete parts from the old to the new platform. New accelerator sections will only be integrated into the new control system platform. For Phase 1 new graphical user interfaces have been implemented for operators and machine physicists. New application servers collect and archive machine data, generate 24h trend charts, which are also accessible by internet via WAP protocol, and send alarm messages when required. The paper discusses the added value gained by using a commercial system and to which extent the commercial system covers tools and features which were part of the previous system and its operational procedures