Dear TA Collaborators,

The following is the minutes of the SD meeting in ICRR on May 22nd.

1) Front-end specification
1-1) General
 Yoshida_san explained the global specifications based on the web. 
 In Akeno test, front-end electronics without AMP (solution 1) will 
be tested since it exists, while the one with AMP (solution 2) will 
be tested in parallel. In Akeno test, we can control through RS232C 
and save data onto the disk by dumping screen log. We need shaper 
in order that multiphotoelectron signals can overlap smoothly.

1-2) Ohka_san's front-end electronics
 There is one set of Front-end electronics Rev2. It will take about 
2 weeks for 4 sets ( 2 boards for one stand ). It has a function of 
digital trigger, which we can use in Akeno test. It also has an 
input of external trigger. Basically the extension and integration 
with some feedback from the test will lead to the electronics for 
Utah test.
 Ohka-san designed FADC with DAQ for GPS test in Mizusawa. The spare
boards can be used in other unversities such as Chiba University.

2) PMT specification/Calibration
 Linearity of all PMTs will be checked (Chiba U. and NIRS).
 OCU will check uniformity and temperature dependence for some PMTs,
and will conclude how to check these items for mass production. 
( The check of temperature dependence may take about half day. )

3) Scintillator/Housing
 Kawakami_san presented the plan of mass production of scintillation
counters. It's necessary to determine the method of mass production 
for several items such as assembly of the counters, connection of 
cables to outside, and the connection between fibers and PMT. 
HV power supply will be selected after the tests such as temperature
dependence. The method of fixing scintillators and PMTs in the box 
has to be determined. The procedure of assembly, transfer, 
installation, and adjustment has to be clarified. Some ideas such as
light guide method, holes for WLS in scintillators rather than 
slots, and painting rather than wrapping were raised by Ozawa, which
will be examined within quick time span.  

 Sagawa reported the status of the 1st prototype of SD housing, 
which was delivered at Akeno on May 17th. It is required to lower 
the total cost and the weight of the stand towards the final specs.

4) Slow control
4-1) General
 Nakamura_san listed items of monitors such as charge & power 
control, HV control for PMTs, thresholds for signals, and 
environmental monitors (temperature, humidity etc.). He will 
summarize and propose the items by taking into account the 
discussion in the meeting. Ozawa_san will take care of I/O part.

4-2) Solar power system
 Two SHARP solar panels (NE-70A1T), a deep cycle battery (SEB100),
and a charge controller (SS-10L) will be tested for Akeno Test. 
Purchasing solar panels and a battery in the US is probable from 
the point of cost reduction including the choice of 12V or 24V. 
The choice or design of charge controller has to be determined. 

5) GPS
 The test of GPS of each company will be performed early in June 
to determine which GPS is chosen.

6) Akeno Test
 The 1st prototype of SD stand with a scintillator box was delivered
on May 17th. The assembly of scintillators with WLS and PMTs was 
completed, and the results of cosmic-ray signals were demonstrated. 
We will perform the test by using existing instruments and materials
for the time being, and would like to determine the specification in 
June. Ozawa_san is going to arrange and post the schedule for Akeno 
Test. 

7) Test of Wireless LAN in Aso
 Transmission in a 19.7km away distance was successful with a plain 
antenna and ADLINK modem. The next issue is how we check the effect 
of the ground shape, and also there is a issue of FCC. 

8) Height of communication towers and the number of the surface 
detectors
 Takeda_san showed the number of the surface detectors to be 
ommunicated as a function of the height of communication towers. On 
condition that the height of the towers is 30m or less, at least 17 
surface detectors cannot be communicated. At least 15m is necessary 
for the height of towers, by which 44 detectors around the boundary 
are removed if the portions on the plateau are removed and smooth 
boundary is required in additon ( 57 detectors, which is about 10% 
among 576, are removed if the portion, which is protruded at the 
north side, is removed further).

9) BLM
 The following guide was raised at the meeting with BLM in Utah on 
May 18 (Tue).
First:  Stake all 576 sites.
Second: Show the detector and explain deployment meas.
Then:   Plant, animal, and cultural resources survey will be 
        performed.
The plan of staking all sites on June will be porposed by Kai next
week.

10) MC simulation
 Hybrid MC concept was presented. C++ language will be chosen. 
Simple sample program is being prepared now.

11) Schedule towards the Utah test
 The schedule towards the SD engineering array test for 10-20 sets 
in Utah was summarized at the end of the meeting. The brief contents
are as follows:
. Decide most of the specifications by the end of June
. Finish most of the productions by the end of August
. Sent parts from Japan to Utah on September
. Start the assembly, the installation, and the test on October
. Complete the full engineering array by the beginning of November  
Detailed schedule is put on 
http://www.ppl.phys.chiba-u.jp/research/TA/

That's all.

Best regards,
H. Sagawa (ICRR)