Emails from John Tucker

Letter from John Tucker to John Coster-Mullen, who had forwarded my info to Mr. Tucker:

From: John Tucker

Sent: Sunday, February 11, 2007 1:48 PM

To: John Coster-Mullen

Subject: Re: Your father

Hi John.

Yea that's me with the mustache. We had a bet on the four of us,

Prohs, Okeefe, Reynolds, & myself. The first one to shave their

mustache would forfit their weeks beer ration, all of three cans. I

got a cold and couldn't stand the mustache, so I shaved it off.

Harms has some interesting pictures. I remember the father Harms, a

real nice guy and a very knowledgeable electronics person. I will get

in touch with Kurt, but I won't be able to help him much with names.

Thanks for forwarding Harms email.

John

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John Tucker’s subsequent email to me on 2/12/07:

Hi Kurt,

John CosterMullen forwarded your emails to me. I am John Tucker and

was a member of the Los Alamos Destination. I was on the x-unit team

and knew your dad.

I was an Ensign in the Navy. I served at Oak Ridge, Los Alamos,

Wendover and the 509th, and on Tinian. I knew your dad since he and I

were in the same Group, the X-Unit Group. I also traveled with your

dad back and forth to Wendover for a brief time to build prototype

weapons for testing by the 509th Group. I also flew three training

missions as the Weaponeer from Wendover. I left Los Alamos in December

1945, but returned in December 1947 to work in the Detonator Group. I

spent the rest of my working career there, retiring in 1982 and

consulting for another ten years or so.

Your dad was a very knowledgeable and bright young man with great

expertise in electronics. I was a few years older than he. I am sorry

to hear of his death. He and the other SED's in our Group had

obviously been hand picked for their knowledge and abilities by someone

for that particular job.

The SED's did change from their Army uniforms to civilian on the plane

to Wendover and the reverse on the way back to Albuquerque. The reason

was that they would be working with the assigned members of the 509th

Special Engineer's and as such could possibly direct the work of an

officer. My impression was that this was a precaution by Los Alamos so

as not to cause any possible conflict between officers and enlisted

people. Later on Tinian the Wendover people learned the truth, and it

did not cause a problem over there.

You have some very interesting pictures, some of which I have seen, and

a couple that I have copies of.

I am not sure that I can help you a whole lot, however, I would be

willing to give it a go.

John Tucker

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My response to John Tucker’s 2/12/07 email:

Hi John,

I was delighted to get your email. I've finally made contact with someone who knew my dad when he was working on the Manhattan Project! I guess you saw my original letter to John Coster Mullen, so I'll try not to rehash any of that.

I loved hearing the uniform/civillian clothing story, as I remember my dad talking about that when I was growing up. I think he might have gotten a kick out of a lowly tech sergeant giving instructions to an air force officer. (Nice to hear that, ultimately, it probably wouldn't have bothered anyone.)

My biggest question, I think, would be this: What, exactly, was my dad responsible for doing in the construction of the bomb on Tinian? I know electronics was his specialty, and I know he had something to do with the triggering device and the X-Unit (which I find mentioned in many books but never explained particularly well--I may have to buy Coster Mullen's book). On one of his resumes he wrote that he "was credited with some original work on the final bomb design," and while I imagine the same could be said for many SEDs on the project, I'd sure love to find out what he got credit for.

I think I recall some stories or letters about him actually visiting Raytheon because of the delays on the X-Unit. Is that likely?

Dad also mentions "assisting" in the Trinity test on his resume, but if I'm reading his orders correctly he was already off to Tinian before the test. Do you know what that might've involved? Do you recall approximately when your group started going to Wendover for the 509th testing, and how often you might've traveled back and forth before heading to Tinian? When might my dad have started these trips? From what I can tell, dad's group had orders to go to Wendover and then on to Tinian about July 5, 1945, but I really have no idea what his timeline looks like before that. Any gaps you might fill in for this period would be appreciated.

What did you guys do to pass the time on Tinian? Any mischief, interesting hikes around the island, or good stories about putting the bomb together? (I read about B.J. O'Keefe having to un-solder and reconnect some male-female end connectors that had been installed in reverse a day or so before the bomb needed to be ready--what a nightmare!)

What was going on with you guys on Tinian after Nagasaki? How long did you stay there, and when did you head back to Los Alamos?

Was my dad back at Los Alamos by the time of the Daglian criticality accident late in August of '45? I remember him talking about a "brick" falling and leading to a supercritical mass, and Daglian pushing the brick away with his hand. This must've left quite an impression on my dad, as I found a lengthy article cut out of a newspaper that he kept about the incident. Was the Project Alberta team back at Los Alamos by this time?

Sorry--upon rereading I sound like a high school student doing a research paper. Guess I don't have to ask all my questions at once. Wish I'd asked dad these questions when I had the chance.

Thanks again, John.

--Kurt Harms

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John’s response on 2/14/07:

Hi Kurt,

I will try to answer some of your questions, however, I probably will

be unable to answer all that you would like. I would suggest that you

look into the following web sites for additional information, if you

have not already done so.

http://www.mphpa.org/classic/VET_ARCHIVES/MPVA_04.htm#tucker

www.mphpa.org, www.mphpa.classic/index.htm

Your dad, with other SED's, navy officers, army officers, and

civilians, worked in the x-unit Group, which was the group that

designed the firing unit to fire the detonators of the Fat Man Bomb.

The civilian members included several Physic professors from various

universities. The Group as a whole was very high caliber, if you

exclude a few like my self. I am guessing that the Group probably had

about 30 people, plus or minus a few. One of the guys, a civilian Don

Hornig would later become a presidential advisor. Other civilians

would be professors at Princeton, Harvard, and John Hopkins. A few

SED' would become professors of chemistry and physics at other

universities. I do not really know all the particulars.

In one of the pictures that you had of myself, Ens. Prohs, Ens.

Reynolds, and Ens. Okeefe; Ens Okeefe would later become president and

CEO of EG&G. Ens. Reynolds was then a professor of Physics at

Princeton. A Dr Edgerton, a consultant to the Group, later copartner

of three MIT professors that formed EG&G, was the primary developer of

the high voltage, high capacity condenser that stored the energy to

fire the detonators. I also think that he was perhaps the primary

developer of the spark gap that was the switch to discharge the two

capacitors into the load ring and cables that distributed the energy to

initiate the detonators. The x-unit had two capacitors to provide the

firing energy. The system was redundant, because of the high rate of

detonator failure. Each detonator had two bridge wires each connected

to one of the two capacitors.

The Group in addition to developing the x-unit, getting it built at

Raytheon, was responsible for inspection the x-units received from

Raytheon which ment their disassembly, inspection and testing of

components, reassembly, testing the unit as a whole, mounting the

x-unit onto the weapon, attaching and routing the firing cables from

the load ring to the detonators, and helping to finnish the

installation of the external bomb casing. Group members were involved

in various portions of these activities.

I do not know how much you dad was involved in the design of the

x-unit. I got to Los Alamos in middle to late March 1945 from Oak

Ridge. The morning after I arrived, I was told to join a bunch of

people down the hall. There we spent at least two days and one night

building the first breadboard prototype, testing it, and shipping it

off to Raytheon for them to build the real thing. We were allowed to

go down the hall to the bath room, our meals were brought in, if we got

too tired to continue we cleared a space on a bench and sacked our for

a while. There were civilians, SED's, and Navy guys in that room. I

was so new that I did not know a single person, however, I imagine that

your dad was probably a part of that exercise.

Later, I along with your dad and other SED's, Navy, and civilians

traveled back and forth to Wendover to disassemble, test components,

reassemble, and mount to prototype weapons for flight testing. We were

transported to the Albuquerque airport by taxi driven by WACS. At the

airport there would be a 509th C45, DC-3, waiting. We would load up

our gear, board the plane, and take off. The SED's would change to

civilian clothing. We flew west out of Albuquerque until we hit the

Grand Canyon, they they flew north up the canyon, until they turned

west to Wendover. We did the reverse on return. We usually left Los

Alamos on a Monday or Tuesday, and returned on a Friday. At Wendover

we were assigned a few members of the First Ordnance Squadron to assist

us in our work.

On July 4,1945, Ens Prohs, Ens. Okeefe, and I left San Francisco to go

to Tinian by air. Ens. Prohs was a member of the Radar Group that was

responsible for the Fuzing, safe separation timing from delivery plane,

radar burst height, barometric bust height, and contact fuzing. Ens.

O'keefe and I were of the x-unit Group. Our purpose was to get to

Tinian and begin setting up our work facilities, find and set up all

materials previously sent, with help form the 509th 1st Ordnance people

that were already there.

After the Trinity test, the rest of the Los Alamos people came to

Tinian by air. Your dad was in that Group. After Nagasaki there was

not much to do. We did not have any active material for any more

bombs, however, we expected to stay on until we did. After Japan quit

we came home by Green Hornet, a 509th C-54.

Something has come up and I have to sign off and go do that. Hope the

above is some help.

John

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My response to John’s 2/14/07 email:

Hi John,

I want you to know I am deeply grateful for your detailed response. I appreciate the time and effort you took in answering my questions.

I am a bit confused about when dad went to Tinian. Growing up I thought he might have taken part in the Trinity test, but upon reading some of his papers recently I found he had orders to go to Tinian "on or about July 5," with these men: Eugene Sabatino, William Murphy, Gunnar Thorton, Leonard Motechko, and Benjamin Bederson. That would mean he left Los Alamos before the Trinity test on July 16. If you can settle this question for me, I would be delighted.

What building(s) in the tech area at Los Alamos would you have worked at? Do you know where my dad's group would have been?

Thanks again for sharing your information with me. I'm sure you have many other things to do, and I appreciate your time.

Kurt Harms

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John’s reply, 2/19/07:

Hi Kurt,

I have never sent an attachment, but I tried, but am afraid that I sent

it without a message. If the attachment got sent, you can see that

your dad was mentioned in the letter as a recipient.

I do not know when your dad and the others got to Tinian. However, it

probably was before the Trinity Test since they did not travel with us

or before us.. I took this attachment from the "Wendover Memories,