# Agenda for 9/4/03 Femtosecond Thursday meeting at 1:00 pm in 6-1105

Laser System Update -- Wilcox

Chicane Magnet Radiation - Heimann

**Minutes.**

#### Laser System Update

Russell Wilcox provided an update on the laser system. The oscillator
and pump laser for the front end have been delivered and tested. Four
pump lasers for the power amplifiers have been ordered and two are
scheduled for delivery next week. A prototype power amplifier has been
built and tested in the lab at low repetition rates and without
cryogenic cooling. The measured gain is in good agreement with model
calculations. An additional 2x in gain may be possible with a more
complex 4-pass scheme (including AR coated windows and crystals). The
cryogenic cooler (Cryomech AL300) and associated vacuum chamber for the
power amplifier has been built and tested with a resistive thermal load.
Measurements of vibrational coupling to the table from the cryo head
show \~1μrad beam pointing fluctuations (peak to peak). The Ti:sapphire
crystals have been mounted in this chamber.

Russell presented a modified schedule that calls for laser work to begin
at the ALS in December 2003. Some negotiations are still pending with
BL5.3.2 (regarding hutch modifications), with BL6.3.1 regarding floor
space, and with ALS User Services, Gary Krebs (regarding relocation of
equipment that is now in the BL6.0 laser area). The target date for
laser operation at 20 kHz is January of 2005, and 40 kHz operation is
expected in March of 2005. An additional remaining issue is to check the
laser beam path across the roof blocks (from the periscope in the laser
area to the back-tangent port in sector 4).

#### Chicane Magnet Radiation

Phil Heimann gave an overview of the issues regarding radiation from the
chicane bend magnets and from the insertion device(s), their respective
overlap, and contribution to the background. Three important questions
were addressed:

\(1\) Are the insertion device engineers and beamline engineers using
the same bend angles -- both are using 2.16 mrad.

\(2\) Is 2.16 mrad sufficient to isolate radiation from two insertion
devices?

In-vacuum undulator/wiggler - opening angle is ±K/γ = ±1.2 mrad

EPU opening angle is ±1.1 mrad

2.16 mrad seems to be OK, but the radiation distribution needs to be
calculated at specific photon energies.

\(3\) Will other radiation points (specifically the chicane magnets)
contribute to the background?

The chicane magnets are 0.2 T, so they will contribute primarily in the
soft x-ray range (\<2 keV). The intensity is \~300x weaker than the
radiation from the IVID, but it is poorly focused, and this needs to be
considered in more detail. The upstream bend is displaced by 2 mm and is
100x weaker than the IVID at 500 eV, so this should not be a major issue

**Action Items (Updated)**

Steve\-\-\-- verify complete inventory of vacuum vessel material stored
at 901.

Steve\-\-\-\--look at alternate magnetic design with reduced higher
order harmonics.

Christoph\-\-\--Conclude longitudinal field harmonics study by end of
September.

Howard/ Bob\-\--schedule a meeting with BCSB management to present
installations plans for

W11

Dave P.\-\--work with Tony Catalano to develop the beamlines schedule
consistent with engineering manpower availability, yearly funding
requirements, and to document scope.

All -- risk mitigation plans

Christoph/Ross/Steve\-\--resolve ID field and roll-off issues

Steve\-\--Collect data from the three existing designs for the power on
the RF shield for the IVID.

Alan---address engineering manpower issues.

All\-\-\-\-\--update review presentation book.

Check options for W16 cost recovery with Gavin Robillard\-\-\--Alan

(Steve reports from Robillard that if another national lab expresses
interest in W16, we can only expect them to pay incidental costs of
removal from the ring, packing, shipping etc.)